Taxonomy Term http://www2.buildinggreen.com/blogs/1794/Riversong%27s%20Radical%20Reflections en 8986 Fire Risks Not Limited to Spray-Foam Insulation

Spray foam is only one of a number of building products and methods which increase the risk of catastrophic fire loss (and potential loss of life).

[Editor's note: After asking him to pen his series of 10 Riversong's Random Reflections on our blog earlier this year, we asked Vermont builder Robert Riversong back to discuss fire safety issues in residential construction. Riversong is a volunteer firefighter. Enjoy! – Tristan Roberts]

A Builder/Firefighter's Thoughts on Fire Issues in Residential Construction and Remodeling

There has been some media and regulatory attention given lately to auto-ignition of spray polyurethane foam (SPF) insulation during the application process. [Editor's note: see Massachusetts Fires Tied to Spray Foam Incite Debate.]  While the SPF industry has, understandably, reacted defensively to this development, there are legitimate reasons for caution and concern.

The SPF industry has taken an industrial, chemical process that works quite well in the controlled setting of a highly-regulated factory with in-house and outside safety specialists monitoring the process--and set it loose in the field in an uncontrolled environment, with far less consistent applicator training and an impossibly difficult arena for safety monitoring. A significant increase in application errors is to be expected, particularly when thickness limits are ignored in order to complete a job or to meet IECC R-value standards.

However SPF is only one of a number of relatively "modern" building products and methods which increase the risk of catastrophic fire loss (and potential loss of life). As with almost all technological advances, there are unintended consequences that are not either recognized or considered in the rush toward market acceptance.As one who has been both a designer/builder and a volunteer firefighter for 30 years, as well as an instructor in sustainable design and construction, I can shed some light on the issue of fire safety in construction and remodeling.

Dangers of truss and engineered lumber construction

One common construction practice has been the use of light-frame floor and roof trusses. These have often been replaced, at least in floors and sometimes roof assemblies, with "engineered lumber" such as wood I-beams. In both cases, structural integrity depends on the synergy of all parts of the assembly, including chords, webs, struts & ties and their connectors (typically metal truss plates). With smaller elements, these engineered structural units fail much more quickly in a fire than either light wood frame or timber frame construction. In trusses, the metal gang nailing plates quickly overheat, char the wood they penetrate and fail.

Even small-town fire departments often have to engage in pre-planning to note which buildings in their jurisdiction are made from truss or engineered lumber construction. An I-joist, like a truss, will also fail more quickly than a comparable 2x joist or rafter. We typically will not enter such a building for interior fire suppression and will avoid going onto the roof to ventilate the heat. This leaves only outside fire suppression and makes the building more vulnerable to fire and water damage as well as collapse.

Ventilating a fire in progress

A non-combustible roofing material may be sensible if using a woodstove for heat or if in a wildfire zone. But with interior-origin fires (which most are), a non-flammable roof such as metal or slate will contain the heat and fire longer and often result in more serious structural damage. One of the first things we firefighters do at a structure fire is to cut one or more holes in the roof to ventilate the super-heated air. Sometimes breaking windows is sufficient unless the fire is already in the attic.

Early morning of April Fools Day, 2008, my department responded to a structure fire in our central village--a former home and barn used as a spa/salon and an antique store. The fire was triggered by a propane explosion, and the building was fully involved at our arrival. The building had been renovated so many times that we discovered (after the fact) a number of double walls and a double roof built up over an existing roof. Attempting to ventilate the roof did not work because of the secondary roof below. Outside attack hose streams were blocked by extra walls just inside the windows, and the fire chases created by the doubled interior partitions increased the rate of fire spread. Unintended consequences.

Cellulose implicated in convenience store fire

In August of 2006, our department was called to a convenience store under construction after the original one burnt down and a new model replacement (which was meant to be the prototype for all similar stores for this locally-owned Vermont chain) also burnt to the ground just two months earlier. It seems the same cellulose insulation contractor who had blown the suspended ceiling the day before the previous fire was at the site filling the ceiling again. This time, an employee noticed smoke coming from the hopper of the truck-mounted blowing machine, so he stopped the operation and emptied out the hopper. At the bottom, just above the overheated muffler from the compressor, was some charred cellulose.

If properly treated with borates, cellulose is one of the most fire-proof insulations on the market. While it won't support combustion, it will char and smolder. Apparently, two months earlier and with the same blower, this contractor had put some smoldering cellulose into the ceiling. Overnight, it ignited some non-protected framing member, which spread the fire to the entire hollow ceiling and metal-clad roof. Almost as soon as the fire department arrived, the entire roof collapsed. Unintended consequences.

I was the firefighter who collected samples of the charred cellulose from the second reconstruction and got it to the state fire inspector. The earlier fire was then determined to be caused by a faulty cellulose machine and that contractor went out of business. We provided water while a septic pumper sucked all the new cellulose out of the ceiling and saved the store from a third fire.

While cellulose-related fires are an aberration (cellulose is so effective at fire prevention that it's been third-party certified as a fire stop), there are an infinite number of potential errors which can result in a fire during construction (two of the most common are oily rags auto-combusting and space heaters left unattended).

Choose building materials with care--and think about unintended consequences

The lesson is that care and consideration are required, both in choosing materials and methods and in maintaining a safe construction site environment. Some materials, such as plastic foams, can dramatically increase fire risk – both in application (ASTM E85, referenced in IRC R316, sets flammability standards and thickness limits, which are often less than code-minimum R-values) and during occupancy. If foam insulation is part of a structural panel system, then the structure can collapse once the melting point is reached or the required 15-minute ignition barrier is breached. Once burning, plastics accelerate fire spread, smoke development and building damage.

Using non-flammable materials and avoiding fire chases (including the exterior chase created by a rainscreen cladding system) can help reduce both the likelihood of fire and the extent of fire damage. Make sure there are adequate fire stops in all enclosed soffits, attic kneewall areas, under first floor bathtubs and around chimneys. Install wood-burning appliances (and all combustion appliances) to factory specifications and according to applicable fire codes.  Design in fire egress windows in all sleeping areas, and a safe route to the ground. Beware of wildfire zone issues and codes. Of course, install hard-wired smoke and CO alarms and make sure any exhaust flue exits the house above maximum snow level to avoid CO back-drafting.

But, above all, think about potential unintended consequences. Every design and construction decision has the potential to increase or reduce the risk, intensity and extent of fire. About 4,000 people die every year from fire in the US, and the almost 400,000 annual residential fires create nearly $8 billion in losses. These are consequences best to anticipate and avoid.

Editor's note: BuildingGreen's guide to insulation materials and practices helps readers navigate some of the material choices alluded to here.

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-11-02 n/a http://www2.buildinggreen.com/blogs/fire-risks-not-limited-spray-foam-insulation http://www2.buildinggreen.com/ 8987 Fire Risks Not Limited to Spray-Foam Insulation

Spray foam is only one of a number of building products and methods which increase the risk of catastrophic fire loss (and potential loss of life).

[Editor's note: After asking him to pen his series of 10 Riversong's Random Reflections on our blog earlier this year, we asked Vermont builder Robert Riversong back to discuss fire safety issues in residential construction. Riversong is a volunteer firefighter. Enjoy! – Tristan Roberts]

A Builder/Firefighter's Thoughts on Fire Issues in Residential Construction and Remodeling

There has been some media and regulatory attention given lately to auto-ignition of spray polyurethane foam (SPF) insulation during the application process. [Editor's note: see Massachusetts Fires Tied to Spray Foam Incite Debate.]  While the SPF industry has, understandably, reacted defensively to this development, there are legitimate reasons for caution and concern.

The SPF industry has taken an industrial, chemical process that works quite well in the controlled setting of a highly-regulated factory with in-house and outside safety specialists monitoring the process--and set it loose in the field in an uncontrolled environment, with far less consistent applicator training and an impossibly difficult arena for safety monitoring. A significant increase in application errors is to be expected, particularly when thickness limits are ignored in order to complete a job or to meet IECC R-value standards.

However SPF is only one of a number of relatively "modern" building products and methods which increase the risk of catastrophic fire loss (and potential loss of life). As with almost all technological advances, there are unintended consequences that are not either recognized or considered in the rush toward market acceptance. As one who has been both a designer/builder and a volunteer firefighter for 30 years, as well as an instructor in sustainable design and construction, I can shed some light on the issue of fire safety in construction and remodeling.

Dangers of truss and engineered lumber construction

One common construction practice has been the use of light-frame floor and roof trusses. These have often been replaced, at least in floors and sometimes roof assemblies, with "engineered lumber" such as wood I-beams. In both cases, structural integrity depends on the synergy of all parts of the assembly, including chords, webs, struts & ties and their connectors (typically metal truss plates). With smaller elements, these engineered structural units fail much more quickly in a fire than either light wood frame or timber frame construction. In trusses, the metal gang nailing plates quickly overheat, char the wood they penetrate and fail.

Even small-town fire departments often have to engage in pre-planning to note which buildings in their jurisdiction are made from truss or engineered lumber construction. An I-joist, like a truss, will also fail more quickly than a comparable 2x joist or rafter. We typically will not enter such a building for interior fire suppression and will avoid going onto the roof to ventilate the heat. This leaves only outside fire suppression and makes the building more vulnerable to fire and water damage as well as collapse.

Ventilating a fire in progress

A non-combustible roofing material may be sensible if using a woodstove for heat or if in a wildfire zone. But with interior-origin fires (which most are), a non-flammable roof such as metal or slate will contain the heat and fire longer and often result in more serious structural damage. One of the first things we firefighters do at a structure fire is to cut one or more holes in the roof to ventilate the super-heated air. Sometimes breaking windows is sufficient unless the fire is already in the attic.

Early morning of April Fools Day, 2008, my department responded to a structure fire in our central village--a former home and barn used as a spa/salon and an antique store. The fire was triggered by a propane explosion, and the building was fully involved at our arrival. The building had been renovated so many times that we discovered (after the fact) a number of double walls and a double roof built up over an existing roof. Attempting to ventilate the roof did not work because of the secondary roof below. Outside attack hose streams were blocked by extra walls just inside the windows, and the fire chases created by the doubled interior partitions increased the rate of fire spread. Unintended consequences.

Cellulose implicated in convenience store fire

In August of 2006, our department was called to a convenience store under construction after the original one burnt down and a new model replacement (which was meant to be the prototype for all similar stores for this locally-owned Vermont chain) also burnt to the ground just two months earlier. It seems the same cellulose insulation contractor who had blown the suspended ceiling the day before the previous fire was at the site filling the ceiling again. This time, an employee noticed smoke coming from the hopper of the truck-mounted blowing machine, so he stopped the operation and emptied out the hopper. At the bottom, just above the overheated muffler from the compressor, was some charred cellulose.

If properly treated with borates, cellulose is one of the most fire-proof insulations on the market. While it won't support combustion, it will char and smolder. Apparently, two months earlier and with the same blower, this contractor had put some smoldering cellulose into the ceiling. Overnight, it ignited some non-protected framing member, which spread the fire to the entire hollow ceiling and metal-clad roof. Almost as soon as the fire department arrived, the entire roof collapsed. Unintended consequences.

I was the firefighter who collected samples of the charred cellulose from the second reconstruction and got it to the state fire inspector. The earlier fire was then determined to be caused by a faulty cellulose machine and that contractor went out of business. We provided water while a septic pumper sucked all the new cellulose out of the ceiling and saved the store from a third fire.

While cellulose-related fires are an aberration (cellulose is so effective at fire prevention that it's been third-party certified as a fire stop), there are an infinite number of potential errors which can result in a fire during construction (two of the most common are oily rags auto-combusting and space heaters left unattended).

Choose building materials with care--and think about unintended consequences

The lesson is that care and consideration are required, both in choosing materials and methods and in maintaining a safe construction site environment. Some materials, such as plastic foams, can dramatically increase fire risk – both in application (ASTM E85, referenced in IRC R316, sets flammability standards and thickness limits, which are often less than code-minimum R-values) and during occupancy. If foam insulation is part of a structural panel system, then the structure can collapse once the melting point is reached or the required 15-minute ignition barrier is breached. Once burning, plastics accelerate fire spread, smoke development and building damage.

Using non-flammable materials and avoiding fire chases (including the exterior chase created by a rainscreen cladding system) can help reduce both the likelihood of fire and the extent of fire damage. Make sure there are adequate fire stops in all enclosed soffits, attic kneewall areas, under first floor bathtubs and around chimneys. Install wood-burning appliances (and all combustion appliances) to factory specifications and according to applicable fire codes.  Design in fire egress windows in all sleeping areas, and a safe route to the ground. Beware of wildfire zone issues and codes. Of course, install hard-wired smoke and CO alarms and make sure any exhaust flue exits the house above maximum snow level to avoid CO back-drafting.

But, above all, think about potential unintended consequences. Every design and construction decision has the potential to increase or reduce the risk, intensity and extent of fire. About 4,000 people die every year from fire in the US, and the almost 400,000 annual residential fires create nearly $8 billion in losses. These are consequences best to anticipate and avoid.

Editor's note: BuildingGreen's guide to insulation materials and practices helps readers navigate some of the material choices alluded to here.

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-11-01 n/a http://www2.buildinggreen.com/blogs/fire-risks-not-limited-spray-foam-insulation-0 http://www2.buildinggreen.com/ 9032 How to Get the Shelter We Need, and Nothing More

Not only can the earth no longer afford our petrochemical picnic cooler McMansions fueled by coal, oil, gas and nuclear power, but also, our psyches can no longer tolerate such exaggerated encapsulation.

[Editor's note: This the tenth and final piece in a set of reflections by Vermont builder Robert Riversong. Links to the other nine articles are below. Enjoy, and let us know what you think! – Tristan Roberts]

Riversong's Radical Reflections

10. Capping it All Off – Hat & boots and a good sturdy coat

In his seminal 1963 book Never Cry Wolf (made into a Disney movie in 1983), Canadian author Farley Mowat wondered how the Arctic Inuit people could live in caribou skin tents full of holes, until he realized that their primary shelter was the double-layer furred skin clothing they wore year round. Their shelters--summer tents and winter igloos--were merely secondary shelters to offer a modicum of protection from the elements while still retaining a deep connection to the environing landscape which contained and sustained them.

Mowat's other discovery, which helped turn worldwide public opinion from the myth of the "big, bad wolf" toward a deep and abiding respect for this highly social and playful animal which is at the core of the Arctic ecosystem, was that "We have doomed the wolf not for what it is, but for what we deliberately and mistakenly perceive it to be--the mythological epitome of a savage, ruthless killer--which is, in reality, no more than the reflected image of ourself."

Caged Nature and Imprisoned Humanity

The mindset which perceived the wolf as monster was the same paradigm which understood nature as wild and mean and something that needed to be tamed, controlled, and isolated from our daily "civilized" lives. This foundational myth of civilization, which led us to build fences to keep wild nature out of our domesticated spaces, also resulted in the incarceration of humanity in an entirely self-reflective world detached from the ground of our being. The more we denied the wildness of our own selves, the more we projected our suppressed carnality onto such creatures as wolves, and the more thoroughly we enclosed ourselves within both philosophical and material cages. The Inuit people shared the land with wolves and caribou, and were comfortable and content with a hooded anorak, skin trousers and a pair of mukluks--hat and boots and a good sturdy coat. We would be wise, as well, to think of our shelters as the same kind of essential wardrobe.

The Web-of-Life on a Gaian Earth

Deep ecologists, eco-psychologists, cutting-edge scientists, Earth poets and millennial philosophers are re-learning what indigenous peoples have always intuitively known: that we are part of a great Web-of-Life, inseparably intertwined and interconnected with all of the animate world and the living earth which birthed and nurtured us. To disconnect from our physical, emotional, psychological and spiritual life-support system is to invite a living death. There are no immutable boundaries in nature – all things are permeable and fluid, and all created things return to dust to become food for new creation. Our shelters need to be the same.

To be truly sustainable, our homes must be built of nature's gifts – natural materials as little removed from their source and as little processed as possible. This means local, low-tech, biodegradable, permeable, respectfully harvested and crafted with care. This also means balancing our personal comfort with the needs of the ecology that surrounds us, and enhancing rather than degrading the evolutionary flow of life. That requires doing more with less, making do with simple, small and pleasant, and foregoing excess and unnecessary architectural elaboration.

In his stunning thesis about "the original affluent society" (1968), anthropologist Marshall Sahlins revealed two approaches to well-being. Hunter-gatherer societies engaged in what he called the "Zen road to affluence" – desiring little and having all needs easily met. By contrast, in modern society "man's wants are great, not to say infinite, whereas his means are limited...and the gap between means and ends can eventually be narrowed by industrial productivity" but never fully satisfied.

As many of us moderns have come to appreciate, we have built a most remarkable cultural treadmill upon which we race to catch an always-receding reward. We have made ourselves into addicts of comfort and pleasure, status and wealth--and collectively and individually we exhibit all the signs and symptoms of profound addictive disorder, post-traumatic stress and chronic dis-ease.

Those who have awakened from the trance have shifted to downward mobility, or the back-to-the-land exodus (encouraged by Ralph Borsodi, whose 1934 School of Living influenced Helen and Scott Nearing) or the more recent sustainability and transition movements. The 1960s were a reprieve from "normalcy" for some, in which the constraints and shackles of society were thrown off for a more natural freedom of expression. Backlash, repression, and the horrors of war, civil unrest and serial assassinations made the moment difficult to sustain. But the cleansed "doors of perception" (Blake), along with the budding environmental movement and the first oil shock in 1973, opened the way for the pioneers of passive solar and super-insulated design and construction. I was among those intrepid explorers, having helped build a geodesic dome in 1970 and then delving into low-cost community-based housing in 1980 and specializing in passive solar double-wall houses since 1982.

The Riversong Truss

My contribution was to take John Larsen's retrofit wall truss system and turn it into a resource-efficient method of new super-insulated construction with native rough-sawn lumber – a system becoming known as the Riversong truss wall – filled with dense-pack cellulose and sealed with air-tight drywall. Another generation of innovators is bringing straw-bale and earthen building techniques into the mainstream, often coupled with traditional timber frames, returning our shelter technologies yet further toward the simple and sublime. Natural building is now incorporated into municipal, state and international green building codes.

Not only can the earth no longer afford our petrochemical picnic cooler McMansions fueled by coal, oil, gas and nuclear power, but also, our psyches can no longer tolerate such exaggerated encapsulation, such inviolable distinction between private and public space, or such wasteful and unsatisfying extravagance. Our physiology is deteriorating, our relationships dismembering, our societies disintegrating, as we wander aimlessly in a spiritual wasteland of our own creation.

More than a house, what we truly need is a sense of home – of being at home in a welcoming and generous world which offers a framework within which we can evolve into the animate creatures we have always been. Whole and wholesome and hearty and hale.

For what does shelter truly require? A sound roof, a solid foundation and sturdy walls. A broad hat to deflect the worst of the rain and wind, a tall pair of boots to keep us out of the mud, and a sturdy coat to wrap us against the cold. Enough and no more.

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-07-15 n/a http://www2.buildinggreen.com/blogs/how-get-shelter-we-need-and-nothing-more http://www2.buildinggreen.com/ 9036 Water in Buildings: Part Science, Part Magic

Given how complex we've made our modern residential structures, it takes a hero to delve sufficiently into the mysteries of physics to confront and overcome the adversaries of heat, air and moisture and to transmute them into allies.

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts] 

Riversong's Radical Reflections

9. Hygro-Thermal – the alchemy of mass & energy flow

Hygro-thermal engineering is the analysis and management of the flows of heat (energy), air and moisture (mass) around, inside of, and through a building envelope. As such, it deals with the dense material (earth), the diffuse material (air), the transformative energy (fire) and the fluid medium (water)--and is a form of alchemy, which was the precursor to modern science and philosophy as well as foundation of the hero's journey from a leaden youth to a golden maturity.

Given how complex we've made our modern residential structures, it takes a hero to delve sufficiently into the mysteries of physics to confront and overcome the adversaries of heat, air and moisture and to transmute them into allies. Or, to be more mundane, the task facing every designer and builder of a modern home is to incorporate nature's inexorable laws into every stage of residential engineering--from conception, through design, by way of planning, toward final manifestation, occupancy and maintenance.

Water as Mystery and Magic

We live on a watery planet. Water is the most common "stuff" in the universe, the most abundant material on earth, and the sine qua non of life. Water is the only terrestrial substance that naturally occurs in solid, liquid and gaseous phases, it is essential for photosynthesis, metabolism and the thermo-regulation of our bodies and the earth's climate. In its solid form, it is less dense than as a liquid (so ice floats and allows aquatic life to survive the winter). Water has an abnormally high melting point, which allows liquid water to cover the earth and create a breeding ground and habitat for life.

Water has the highest specific heat of all liquids except ammonia, which facilitates heat transfer in the atmosphere and oceans and moderates temperature extremes. Water has exceptionally high surface tension, which allows drop formation and rain as well as capillary movement within plants and trees as tall as 400 feet. Water absorbs infrared and ultraviolet light, which encourages photosynthesis and regulates atmospheric and oceanic temperatures. Water is an excellent solvent for ionic salts and polar molecules (the universal solvent), which facilitates the transfer of nutrients in metabolism and in hydrologic cycles from the mountains to the sea. Water has the highest heat of vaporization and the highest thermal conductivity of any liquid (except for liquid metals).

As we might remember from school, a water molecule is composed of two hydrogen atoms in a covalent (electron-sharing) bond with one oxygen atom, thus creating an electrical dipole with positive hydrogen charges that bond strongly to solids and to electrically-charged (ionized) materials. The hydrogen bonds keep liquid water strongly cohesive, with high surface tension that creates a "skin" on top that spiders can walk upon and that forms spherical droplets when it falls. That surface tension--coupled with water's strong bonding to solids--creates the capillary action that allows water to climb magically in narrow channels against gravity.

Water's high heat of vaporization--the energy required to break the hydrogen bonds and overcome atmospheric pressure--gives it a great deal of latent (or enthalpic) heat which is given up to its environment upon condensation (which is why fog melts snow faster than warm air, rain or sunshine). This latent heat is lost when warm, moist air leaves a conditioned space in the winter and puts an enormous load on an air conditioner in the summer because cooling below the dew point requires that the additional heat of condensation be removed from the air as well.

Water is always doing its dance. It moves continuously from solid to liquid to vapor and from absorbed bound states to desorbed free states. In other words, condensation is not something that happens only at the dew point--it is just more noticeable then.

Hygro-Thermal Alchemy

Humidity (or absolute humidity) is the mass of moisture in a volume of air (lbs per cubic foot), at a specific temperature and pressure. The mixing ratio (or specific humidity) is the mass of moisture in a given mass of air, and it determines the partial pressure of the water vapor – what we call vapor pressure. And vapor pressure is what drives water vapor diffusion. Relative humidity (RH), is the ratio of water vapor in air compared to the maximum it can hold at that temperature at saturation (100% RH). If half of the saturation volume is present, then the RH is 50%.

However, the curve of the amount of water vapor that air can hold as it increases in temperature is superlinear, such that--at a fixed absolute humidity--the RH will decrease by half with every 20° rise in air temperature. This also means that warmer air can hold an ever-increasing amount of water vapor and has the potential of producing high vapor pressures even at relatively low RH.

Absorption is the bonding of liquid water in the pores of a hygroscopic or hydrophilic material. Adsorption is bonding of water as a thin film on the surface of a solid (internally or externally). The two processes are simply variants of generic sorption, and the reverse process is desorption. Sorption can occur with water in either the liquid or gaseous states, but once water vapor bonds to a solid it loses the energy and freedom of a gas molecule and bonds as a liquid. Once sorbed, energy input forces bulk or surface diffusion into or out of a porous solid--a process also driven by a concentration gradient. Thus moisture diffusion is moved by heat or relative humidity, since the higher the RH the more opportunity for water vapor to condense into a state of sorption. Hence the moisture content (MC) of a hygroscopic material depends largely on RH, and the MC determines the likelihood of mold or decay.

A family of four will contribute 4–5 gallons of moisture per day from the normal activities of breathing, washing, bathing and cooking. A new house can release hundreds of gallons of water in the first year. A tight house can easily be overwhelmed by this moisture load, requiring both spot and whole-house ventilation, which is also necessary to maintain indoor air quality. But, even with indoor humidity controlled, moisture can intrude into the thermal or structural envelope from either inside or outside or from the ground.

Moisture intrusion requires a moisture source (atmospheric, interior, ground, mechanical or stored), a moisture mechanism (bulk movement, air movement, vapor diffusion, capillary action or condensation), a route of entry (gaps and penetrations, air permeable layers, vapor permeable layers or porous materials), and a driving force (kinetic energy, gravity, air pressure, vapor pressure, temperature gradient or surface tension). Moisture accumulation occurs when the rate of wetting exceeds (or is lagged by) the rate of drying and the difference exceeds the safe storage (buffering) capacity of materials. When moisture accumulation coincides with sufficient temperature and time, then problems occur--including mold, decay, rust, swelling, warpage, delamination, truss uplift, efflorescence, freeze-thaw damage, loss of thermal resistance, and insect infestation.

Moisture Management Methods

We have known for some time that moist air movement contributes as much as 100 times as much moisture to a thermal envelope as vapor diffusion through solid materials, so the focus today is on air barriers--both to prevent unnecessary heat loss or gain and to maintain the integrity and durability of the structure. In a cold climate, the dominant moisture drive (by both temperature and pressure gradients) is from inside to out--so it makes the most sense to locate the air (and vapor diffusion) barrier on the interior. The opposite is true in warm, humid climates where there air (and vapor diffusion) barrier should be on the outside. In mixed climates, moisture can move in either direction (and sometimes both at once), so take your pick. Except in the most extreme cold climates (zone 7 or 8), we no longer recommend true vapor barriers, since they are as likely to prevent drying as to reduce wetting (as the moisture drives reverse), but merely class II vapor retarders of about 1 perm (which can be accomplished with latex vapor retarder primer).

Of the various moisture mechanisms, bulk liquid flow and capillarity are the most significant, so careful exterior detailing and ground vapor barriers, capillary breaks and foundation waterproofing are the most important water management strategies. In fact, the four keys to moisture management are the four D's: deflection, drainage, drying and durable materials.

Deflection includes siting and landscaping to minimize exposure, roof overhangs and window sills, and lapped and integrated weather barrier, flashing and siding, and rainscreen claddings.  Drainage encompasses site grading, sub-surface (French) drains, footing drains, roof gutters and downspouts, as well as rainscreens. Drying relies on vapor-open surfaces or rainscreens and sufficient moisture buffers to safely store daily or seasonal moisture until release. And durable materials include both moisture-tolerant elements as well as hygroscopic substances that can absorb and redistribute moisture, thereby reducing local concentrations (cellulose insulation is excellent at this).

What is not, in my natural-law abiding perspective, a sensible moisture management strategy is the use of impermeable materials, such as plastics, vinyl, bituthene and foams to create what I call the Hermetic House (hermetically sealed like a picnic cooler). One thing that we can be sure of is that every house will get wet at some point, and so a drying strategy can be more important than a waterproof approach. Every study that deliberately introduced a leak into either a wall or roof assembly concluded that drying was so significantly delayed by impermeable materials that damage was a certainty.

Another penny-wise but pound-foolish approach is the use of highly vulnerable materials like OSB. For exterior sheathing or roof decking I would never use anything other than CDX plywood or sawn boards (both of which are reasonably vapor-open). Similarly, I prefer #15 felt (ASTM D226, if possible) as a weather-resistant barrier (WRB) rather than the polymeric housewraps that can trap liquid water behind them and lose their water resistance because of surfactants in wood and stucco.

Just as I refuse to go to the extreme of designing or building a vapor-impermeable house, I also believe that air-tightness can be taken to an unnecessary and potentially dangerous extreme. With Passive House standards becoming the ideal for some designers, it is valuable to ask "How tight is tight enough?" The respected building scientist, John Straube, who has had the opportunity to test and observe thousands of houses in Canada's cold climates, has offered an answer that agrees with my own experience and wisdom. Homes with greater than 3 ACH50 (air changes per hour pressurized to 50 pascals with a blower door) tend to have a risk of interstitial condensation; those with greater than 5 or 6 ACH50 tend also to be too dry inside.

Those with about 2 ACH50 tend to perform quite well, while houses with as low as 1.5 ACH50 have problems with high winter indoor RH. This does not mean you cannot design and detail a 0.5 ACH50 Passive House to work well, but the more we go to extremes on any parameter, the more likely that unintended consequences will exact their revenge effects.

An ACH50 of 1.5 to 3 will also result in a natural air exchange rate of 0.1 to 0.2 ACH, which is just sufficient to maintain indoor air quality when the power is down or the mechanical systems are malfunctioning. To me, this allows a house to be fail-safe rather than allegedly fail-proof, and keeps it within the Golden Mean that Horace, Aristotle, Buddha, Confucius and Lao Tzu taught us to honor.

If a house is, indeed, our "third skin," then it must protect us without disconnecting us from the four elements of earth, air, fire and water which comprise our earthly abode, and it must honor the inherent mystical laws of nature's alchemy.

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-07-06 n/a http://www2.buildinggreen.com/blogs/water-buildings-part-science-part-magic http://www2.buildinggreen.com/ 9039 Designing Homes That Live Off Current Solar "Income"

In the last 200 years, humankind has chosen to live off the "principal" of Earth's core natural resources, not the "interest"--solar income. Here's how we can move forward with home designs that get us on a sustainable path.

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts] 

Riversong's Radical Reflections

8. Energy & Exergy – sources and sinks

For three billion years, life has evolved on earth by capturing and converting solar energy in a most elegant and efficient manner. In fact, the green earth annually utilizes 100 terawatts (100 trillion watts), which is six times the energy consumption rate of all of humanity. We clever hominids have lived sustainably within that solar energy economy for 200,000 years. Since 8,000 years ago (the Anthropocene era), however, we've begun as a species to measurably influence the geological and biological evolution of our planet, and in the last 200 years the anthropogenic impacts of the industrial revolution and the consumption of fossil fuels have had impacts on earth's climate and the evolution of life which may very well extend hundreds of thousands if not millions of years into the future.

Because we have chosen to spend the earth's energy capital rather than live--like the rest of life--off the annual income, the hundred million tons of human biomass on earth, along with 700 million tons of domesticated animals and 2 billion tons of crops are competing with the remaining 5–30 million species of life for land and energy. The result is an unprecedented loss of biodiversity at a rate 100–1,000 times background levels, with the prospect of the extinction of half of all living species in the next 100 years--a disaster known as the Holocene extinction, the first in the history of earth caused by a single dominator species.

You might think that, with our oversized brains, we would not act so stupidly. And yet, here we are! While it's not possible to reverse the damage we've already initiated, we can at least attempt to reduce further impacts by a new ethic of conservation.

Sources & Sinks--Energy & Exergy

When we do a heat loss analysis of a house design, we calculate only the quantity of energy required at the point of use and rarely consider the quality of our energy sources. We know from the laws of thermodynamics that energy cannot be created or destroyed, only converted from one form to another, and that higher energy states resolve into lower energy states by the universal process called entropy.

Since we cannot either create or destroy energy, we can neither consume it nor conserve it. What we consume (or not) is order or--in thermodynamics--exergy, which is the opposite of entropy or disorder. The reason that modern humanity is facing the dual crises of fossil fuel depletion and global warming (in addition to general resource depletion, biodiversity loss, pollution and disease) is because of our short-sighted and rapid consumption of highly ordered, or concentrated, exergy in the form of dead dinosaurs and stardust uranium. In just a couple hundred years, we have nearly consumed all the exergy that the universe took 4.5 billion years to accumulate here on earth.

Life is the only anti-entropic agency in the Universe, converting the low-exergy energy of the sun and simple molecules into highly ordered and complex biological creatures, but we're working counter to evolution unless we more properly match our energy sources to our energy sinks in terms of exergy--concentration or quality. In other words, if we need to keep our homes at a modest 70° or so, or heat our water to 140° (to keep it sterile), then we don't need to use a nuclear fission reaction at several thousands of degrees or even a coal, oil or gas fire at several hundreds of degrees. A far better match of input to output would be direct solar conversion, as passively as possible. (By the way, uranium contains about 17,000 times the energy of even extremely concentrated coal, by weight, and the uranium fuel cycle contributes as much CO2 per kWh produced as natural gas--so it makes sense neither from an exergy nor from a global warming perspective, never mind the dangers of radiation and the impossibility of safe storage of spent fuel for 10,000 years).

Passive Solar--Elegant Simplicity

Clearly, the most sustainable option for space heating and hot water is passive solar and solar thermal collectors, and for cooling and ventilation it's low-absorption surfaces, shading and cross-ventilation, evaporative cooling (such as roof ponds or living roofs), or very efficient fans operated by photovoltaics. An extremely well insulated house, even in cold and cloudy New England, can source 30% to 50% of its heating needs from free direct sunlight stored diurnally in appropriate thermal mass. To design a house that's NOT passive solar amounts to a crime against nature.

For the limited purposes of this essay, I will focus on the most simple and cost-effective solar energy capture technology: passive solar. For the most part, passive solar construction is a matter of using that big brain for clever design, and humans have been utilizing this for thousands of years. Nearly two and a half millennia ago, the Greek philosopher Aeschylus wrote, "Only primitives & barbarians lack knowledge of houses turned to face the winter sun." What he didn't know was that "primitives," such as the Anasazi (or Pueblo) people of the American southwest, used the same principles as much as 12,000 years ago.

The elements of good passive solar design include: southerly orientation (within 15° of true south), an elongated south façade, simple geometry, an open floor plan, sufficient south glazing (7%-12% of floor area) with well-insulating but highly solar spectrum open glass (SHGC 0.50 or higher), appropriately sized direct-gain thermal mass for diurnal storage and release, and overhangs or other shading engineered for the latitude (sun angles) to allow entry of winter sun and blockage of summer sun

Effective utilization of free solar heat also requires a very well-insulated building envelope so that the sun can provide a significant percentage of the daily heat load of the house. In cold climates, I would not use less than R-40 walls and R-60 ceilings, and double-frame walls and flat ceilings, insulated with cellulose, provide the most cost-effective strategy for a super-insulated structure that does not require high-exergy materials (such as rigid or sprayed petrochemical foams) to retain low-exergy heat. Strawbale construction with earthen plasters is another low-exergy option.

In addition to this elegantly simple direct-gain method of capturing solar energy, there are also indirect-gain approaches (such as thermo-siphoning air panels and Trombe walls) and isolated-gain methods (such as attached sunspaces or greenhouses), but neither of the latter are as energy-efficient or cost effective as south windows backed by some additional thermal mass. The mass is ideally in the path of the sun, with a low-specularity, highly absorptive (rich-colored) surface, high thermal capacity, moderate conductivity, and 4" thick as a floor or 8" thick as an interior wall. The thermal mass, if it's in the floor, has to also be well-insulated from the ground – though less so than the walls or ceilings because the earth is not as cold as outside winter air and because some earth-coupling helps make the building frost-proof.

In just a few generations, we have shifted from being an "earth-coupled" species to a global culture that uses materials, techniques and technologies to isolate ourselves from the life-giving and life-enhancing qualities of this sunlit planet. In so doing, we have also decoupled ourselves from the wisdom that allowed us to live sustainably within the biosphere for so many millennia.

It's time we return to earth, come back to our senses, and become agents rather than enemies of evolution. There's nothing more intelligent than being in sync with the planet.

 

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-06-30 n/a http://www2.buildinggreen.com/blogs/designing-homes-live-current-solar-income http://www2.buildinggreen.com/ 9042 When designing for comfort, remember perception

Designers and builders often consider bodily comfort when creating living spaces and mechanical systems, but we should not neglect psychological comfort--our perceptions have a measurable effect on our sense of physical comfort.

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts]

Riversong's Radical Reflections

7. HVAC – Maintaining comfort, health and homeostasis

According to the father of humanistic psychology, Abraham Maslow, people have a hierarchy of fundamental needs which require fulfillment in order to allow progress toward the higher human purposes of relationship, self-esteem and self-actualization or (in the more spiritual traditions) enlightenment. At the base of this pyramid are air, water, food, sleep, health and sex (more or less in that order--your mileage may vary). Just above those subsistence essentials are safety and security--or physical and psychological comfort.

Home designers often consider occupant bodily comfort when creating living spaces and mechanical systems, but we should not neglect psychological comfort--for, as we shall see, our perceptions have a measurable effect on our sense of physical comfort, which is somewhat subjective.

Warm-Blooded Creatures

Human beings are homeothermic, or warm-blooded, creatures who generate and maintain a rather narrow range of internal temperature. Internal heat production is determined by our metabolic rate and muscular activity. Just like any power plant, some of our internal energy conversion goes into useful work (or play) and the rest becomes "waste" heat. Excess heat is dissipated through our "radiator"--our skin. So heat exchange with our environment is a function of activity, surface area and ambient conditions. We warm ourselves primarily by muscle activity (think shivering) and we cool ourselves by shunting blood to the periphery and sweating through our skin. We also absorb and release heat through conduction, convection and direct radiation to or from our skin, and we use our big brains to expand our comfort zones by insulation (clothing), shading (hats, overhangs), external heat production (fire), and clever design (passive solar).

The total heat production of an "average" person at rest is 356 Btu's per hour (which can double or triple depending on the level of indoor activity). This is why commercial and industrial buildings require more cooling than heating, at least when occupied, since 500 people sitting and watching a movie are a substantail 178,000 Btu/hour furnace (more if they're eating popcorn).

In a house, occupants contribute both metabolic heat and utility heat from cooking, washing, electrical appliances and our myriad electronic gadgets (with their 24/7 "ghost loads"). The ASHRAE standard for average per person daily heat contribution, based on typical occupancy periods, is 800 Btu/hour. This is why we must include the design occupancy load, for very efficient homes, when calculating either annual energy needs or sizing a heating plant. A four-person occupancy (3200 Btu/hour of internal gains) can constitute a significant portion of the total heating load, and it changes the balance point temperature of the building.

The balance point temperature is the exterior air temperature at which interior gains exactly match external losses and at which no supplemental heat is required. In a very efficient house, with a total heat loss coefficient of 250 Btu/°F·hr, four-person occupancy can effectively move that house from 8500 HDD north-central Vermont to a northern Virginia climate of 5400 HDD. Of course, internal gains are a liability if the house is air-conditioned.

Psychrometrics

Psychrometrics, the study of moist air, gives us some guidance in designing a comfortable indoor environment. This study (see psychrometric chart) takes into account air temperature, air movement, relative humidity and the latent heat of water vapor (which cools as it evaporates but gives up heat as it condenses when we air condition our space, increasing the cooling load).

Human comfort, however, is dependent on not just air temperature, velocity and humidity, but also metabolic activity level, amount of clothing, mean radiant temperature of room surfaces, radiant asymmetry, air turbulence, air temperature stratification, floor temperature and even colors and mood. In fact, studies have demonstrated that perception of comfort is quite subjective and varies among body types and geographic origin.

In addition, perception of indoor comfort is also dependent upon odors, glare from sunlight, glare from ceiling lights and monitor screens, furniture crowding, aesthetics (such as color and style), noise and vibration levels, ergonomics and personal stress. Each of these elements, then, become important design considerations in a house built for human satisfaction.

Predicted Percent Dissatisfied

ASHRAE 55-2004 and ISO 7730 use the metric of "predicted percent dissatisfied" (PPD) and base their comfort standards on an 80% satisfaction rate, which is determined by studies of subjective "predicted mean vote" (PMV) and a standard deviation from the mean. Interestingly, other than relating to clothing and activity levels, these studies have found that age, ethnicity and gender are not significant in determining perceived comfort, while at the same time red literally "feels" warmer than blue.

In general, though, we naked apes prefer conditions as homeostatic as possible. Warm heads and cold feet are uncomfortable, we don't like cold walls (poor windows) or warm ceilings (not a good place for radiant heat). Fast-moving or turbulent air in the winter makes us feel cold, while in the summer it makes us feel better. Floors should be 66°F–84°F and very close to the high end for bare feet in winter, the mean radiant temperature of room surfaces has an equal effect on comfort as air temperature (which is why radiant floors and low-emissivity windows are so appreciated), and people prefer relative humidity of 30%–70%.

Unfortunately, the inanimate objects within and which comprise our homes prefer relative humidity in the 20%–40% range. So, people will ideally compromise with their homes and keep humidity between 30% and 40%, at least in the winter when interstitial condensation can become a health and durability issue.

Putting it to Work

What does all this mean for deciding how to heat, cool and ventilate a home? Central heat, or at least even heat, is preferred. A radiant floor is better than radiators which are better than forced air (except with combined heating/cooling systems, which must be designed to avoid excessive air speed, turbulence and noise), and a radiant ceiling is a poor choice. Very tight buildings are more comfortable than leaky ones because there's less air temperature stratification and fewer drafts. Ceiling paddle fans can help improve comfort in the summer but not necessarily in the winter.

Windows must be designed for daylighting but not glare, reduction of summer radiant gains and winter radiant losses, effective cross-ventilation without introducing noise, and a balance of spaciousness and privacy.

Indoor relative humidity must be carefully controlled--for comfort, health and structural durability--by both point source evacuation and whole-house fresh air exchange with uniform distribution but without drafts, which might require transfer grilles or hallway plenums. All mechanical equipment must be not only efficient but also quiet and acoustically isolated from living spaces.

That might seem like a lot to consider at the design phase, but we modern hominids have narrowed our comfort range considerably since we moved out of caves and skin shelters.

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-06-22 n/a http://www2.buildinggreen.com/blogs/when-designing-comfort-remember-perception http://www2.buildinggreen.com/ 9046 The Building Envelope: Our Third Skin

Our clothing is our second "skin" and our home's envelope is our third "skin." Each must be semi-permeable and able to breathe. This puts my philosophy of building at odds with much of the so-called "green" building movement, which relies heavily on non-breathing, non-natural and ecologically harmful plastic.

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts]

6. Envelope – shelter from the storm, our third skin

What began, centuries ago, as a simple structural envelope with a rudimentary weather barrier, the bone, muscle, fat and skin of our habitations have evolved into rather sophisticated containers that are expected to perform a number of essential functions and remain durable over time. But they rarely resemble any organic natural entity.

What are the essential functions of a home's envelope? Structure, weather-resistance, thermal resistance, thermal capacitance, moisture resistance, air resistance--and a conditional separation between the inside and outside environments. Conditional, rather than absolute, because the outside environment is not (or better not be) antithetical to life, as would be outer space or the bottom of the sea--each of which requires absolute isolation in order to maintain a livable interior space. While the outdoor environment may not always be comfortable, it is never-the-less the matrix which birthed us, which nurtures us, controls the expression of our personal DNA blueprints and our evolution as a species. We have not evolved to live within an isolation chamber or a picnic cooler--a hermetically-sealed house.

Nature is Semi-Permeable

Every boundary in the natural world is semi-permeable, including our cell walls and our integument--our skin. We have learned that we are far more comfortable in a breatheable parka than in a rubber or plastic raincoat, and we still struggle to fabricate a materials more comfortable than wool or cotton. Our clothing is our second "skin" and our home's envelope is our third "skin." Each must be semi-permeable and able to breathe. And each better supports the life they enclose the more they are composed of the natural materials with which our physical bodies evolved and to which we have adapted over many millions of years.

This puts my philosophy of building at odds with much of the so-called "green" building movement, which relies heavily on non-breathing, non-natural and ecologically-harmful plastics, including but not limited to poly sheeting, bituthene membranes, rigid foam board and spray-in-place foams. But it makes it more consistent with the Bau Biologie (biology of the house) and natural building movements, both of which support human and ecological health and measures of sustainability to a far greater degree.

The Skeleton

The "bones" of a house can be logs or heavy timbers or light sawn-lumber repetitive framing, or earth or stone. Sticks, stones and dirt are the traditional materials from which we fashioned human shelter. Earthen walls work best in dry desert-like climates, where earth predominates and thermal mass may be more important than thermal insulation. Stone is appropriate in mountainous or coastal locales where the bones of the earth are easily available and winds are harsh. But in much of the temperate zone of the earth, at least where we have not already cleared the virgin forests, wood is the most available, abundant and useful material – and it's generationally-renewable if we care for our woodlands.

There are many ways to engineer and assemble wood into a structural frame. Traditional timber framing has experienced a modern revival, and is appropriate as long as it does not require a secondary, non-structural frame or foam plastic panels in order to complete the enclosure, and is not so expensive to produce that it supports merely a niche market. The most ecological way to wrap a timber frame is with straw bales and earthen/lime plasters. It is also one of the most healthful envelopes for its occupants. Another healthy envelope that meets high standards for hygro-thermal performance (more on this in essay #9) is a cordwood/masonry structure, which can be made even more healthful and green by substituting either lime mortar or cob (clay, sand and straw) for the Portland cement mortar. One of many advantages to this technique is that it creates the bones, the meat, the fat and the skin all in a single low-tech process. It can, like straw bales, be either structural or infill. Either lime-treated sawdust or borate-treated cellulose can be used as insulation between inner and outer wythes of mortar.

Rough, Green & Strong

But most of today's homes are going to be constructed more conventionally of sawn lumber. Except for the restrictions of building codes in some jurisdictions, there's no reason that local, rough-sawn lumber, either air-dried or green, can't be used in place of often-imported kiln-dried wood. I've been building from rough-sawn and green lumber for more than 20 years. The lack of a grade stamp should not be an issue, since rough lumber is so much stronger than the milled "nominal" equivalent. A full-dimension 2x4–8' stick has 52% more endgrain compression resistance and 78% greater resistance to buckling than a KD 2x4, so it can easily substitute for a KD 2x6.

With smaller and stronger sticks, it's easier to design double-wall envelopes that use no more material than a conventional frame. In 30 years of building variations of double-wall houses, I have found that the most cost-effective, resource-efficient, labor-efficient, thermally-efficient, and hygrically sound wood-framed envelope is a modification of the Larsen Truss (which was developed for retrofits), which has become known as the Riversong Truss. My system uses a 2x4 inner load-bearing frame, stabilized with metal T-bracing, a 2x3 outer chord gusseted with 1x4s and supported at both foundation and rafter tails. Combination sheathing/siding of pre-finished novelty drop spruce (pattern #105) over housewrap, air-tight drywall inner skin and dense-pack cellulose fill completes the package.

Many Ways to Skin a House

But there are many ways to design a double-wall or deep-stud envelope, including in-line or staggered studs on common or separate plates, load-bearing at either the inner walls or the outer walls (or split: floor-bearing inner and roof-bearing outer, which keeps the band joists inboard of the insulation), I-joists as studs, or sheathed stick frame with Larsen Trusses. When I design homes now for other builders to erect, I typically use the split-bearing double 2x4 24" on center frame with staggered studs and exterior plywood sheathing. This not only meets code requirements but is only a variation on the conventional techniques that most framers already know.

For an exterior, breatheable skin, I prefer pre-finished latex-stained solid wood horizontal shiplap or beveled lap siding. If sheathing is included, it is either diagonal boards or plywood, never moisture-vulnerable and poorly-breathing OSB (or its ZIP-wall variation). Interior breatheable skin is drywall with air-tight acoustic caulk or gaskets (as well as sealing between each framing assembly), either finished with latex vapor-retarder primer or coated with gypsum, earth or lime plaster. Insulation is always dense-packed cellulose, blown dry behind the drywall (though insulweb is an option). The final element is some form of extra thermal mass within or contiguous with the conditioned space.

Local, minimally-processed lumber is the "skeleton", the "skins" are wooden boards and gypsum, the "fat" is recycled newsprint with boric acid (fire retardant, mold resistant, insect-proof, vermin-resistant, air-resistant, and sound-proof), and the "meat" is the thermal mass. Together, and composed primarily of nature's gifts, these create an organic integument that meets both the requirements of a good building envelope and the demands of a finite planet.
Images, in order: Cordwood infill Cordwood and earthen floor Bau-biologie chart Larsen truss Riversong truss Double wall

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-06-08 n/a http://www2.buildinggreen.com/blogs/building-envelope-our-third-skin http://www2.buildinggreen.com/ 9049 Choosing foundation materials: A subconscious decision?

We design a house from the inside out and engineer a house from the top down, but we build a house from the ground up. What are the most environmentally sensitive, durable materials?

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts]

5. Foundations – it all starts here: how do we begin?

From the Ground Up

We design a house from the inside out and engineer a house from the top down, but we build a house from the ground up. The foundation is, literally, the basis for everything else--and the old-timers used to say that a house is only as good as its foundation. When our shelters were simple, such as the log cabins of the American frontier, we could mark out our place on earth with four large stones and call that sufficient. But today, we expect much from a foundation. At its most basic, a foundation must couple a building to the ground, transferring gravity loads as well as the wind effects of uplift and overturning and the seismic effects of shear, sliding and collapse. A foundation must also resist lateral soil pressure, hydraulic pressure and frost expansion, and prevent water, water vapor and soil gas (radon) intrusion. It may also be expected to contain mechanical systems, create storage space or contribute to conditioned living space. And, from the design perspective, it creates the "footprint" of the house above--defining its size, shape and contours.

The Semiotics of the Basement

Beyond these mundane functions, the cellar symbolically represents descent, the unconscious, the past, the things we would rather keep hidden. Whatever we build also recreates the primary archetypes of consciousness but, except for the practitioners of the ancient arts of vastu (Hindu), feng shui (Chinese) and sacred geometry (Greek), we have forgotten the importance of aligning space with place, of balancing the inner with the outer, of harmonizing the seen with the unseen.

"We resonate at both cellular and consciousness levels with our environment. By creating an environment around us that is supportive to both our inner and our outer senses, we can enhance rather than alienate our human links with nature. Architecture, when employed as a means of embodying principles of universal harmony can sustain us rather than drain us, so that our homes become our havens, and our work places support our creativity."
– John Koch, Bacchus Marsh, Australia

A Pattern Language

The foundation also sets the pattern for the rest of the structure. If a primary design goal is to minimize a building's ecological footprint, then we must consider reducing the landscape footprint and the landscape impact--including site disruption, tree destruction, length of access, depth of excavation, amount of replacement fill required, alterations in site topography, and effects on the aesthetics and biotic community of the surrounding land.

The qualities of the site and soil should be reflected in our determination of appropriate foundation, including such elements as surface drainage topography, soil percolation capacity, seasonal water table, frost-heave susceptibility, subsoil depth and texture, and soil load bearing capacity.

Cast in Concrete

Finally, foundation materials must be locally available, cost-effective, durable, and ideally have a low embodied energy and global warming potential as well as being non-toxic to either occupants or the surrounding biotic community. Concrete, either cast-in-place or pre-cast or as concrete masonry units (CMUs) is the most commonly used foundation material but also the second most used substance on earth (after water), and it contains extraordinary embodied fossil fuel energy, and a primary contributor to global warming. Concrete has many advantages as a foundation material, but should be used as sparingly as possible. 

Creative Alternatives

For these reasons, I have tended to prefer either rubble-trench foundations (à la Frank Lloyd Wright) or frost-protected shallow grade beams. The dramatic reduction in both excavation and concrete volume that these systems allow can justify the use of an insulated concrete slab if it has the multiple purposes of finished floor (tinting the mix is the least expensive way to do this), radiant heat source, and solar thermal mass storage. I use the rubble trench on wet or poorly drained sites and the frost-protected shallow foundation (FPSF) on flat sites with well-drained soils. The FPSF is now accepted in the international residential code and the design guide is downloadable through NAHB Research Center (toolbase.org).

When I have to build a full foundation, such as a walk-out basement on a heavily sloped site, I prefer the multiple advantages of the ThermoMass®insulation system (or CIC: concrete/insulation/concrete), which has been used for 30 years in large commercial and industrial applications (including precast and tilt-up) and is now being offered (with free technical assistance and training) for cast-in-place residential foundations. This system puts XPS--from 1" to 4" thick--midline in the concrete forms, held in place and tied to both wythes of concrete with 120,000 psi tensile-strength fiberglass rods 12" on center. This offers the strength of a full 8" concrete wall but with a capillary and thermal break that's protected from UV, insects, physical damage and fire exposure. It also offers almost the same dynamic thermal mass advantage of exterior-insulated concrete. It does, however, require a concrete pumper and a particular mix to fill the 4" form spaces.

Other, less conventional foundation options that are available for consideration include the All-Weather Wood foundation (pressure-treated sills, framing & plywood on a crushed stone base), insulated pre-cast concrete walls (that require heavy shipping), and the increasingly popular Insulated Concrete Forms (ICFs). But the latter puts the foam in the worst possible location--both outside and inside, where it's vulnerable to all the potential dangers--and provides little dynamic thermal mass factor.  

Other somewhat more green ICF products include Rastra (recycled EPS/cement), Faswall (wood/cement with mineral wool inserts), and Durisol (wood/cement with mineral wool inserts), which are breathable, fire and insect-resistant systems that can be cut and machined like wood, hold fasteners, and make good substrates for stucco or plaster. Mineral wool, more commonly available in Canada than the U.S., is also a greener option for foundation insulation on conventional poured concrete or CMU walls. While it's not rated for subslab applications, it's apparently being used in Europe for that purpose.

Protection from the Storm

There are many foundation waterproofing products available today, but I prefer brush-on UGL Drylok latex masonry sealer for its ease of application, concrete-grey appearance, and vapor permeance. As with all parts of a thermal envelope (that's the next installment in this series), a foundation should be able to breathe. On a SFPF with exterior XPS, I trowel on 1/8" of surface bonding cement over ½" hardware cloth for protection and aesthetic.

Setting the Stage

So, even though a cellar might represent the unconscious domain of the archetypical inner sanctum, building "green" requires that we not choose materials and methods unconsciously. As the basis for everything constructed above it, a foundation should set the stage for the design goals of any building project. Images, in order of appearance: Rubble trench foundation SFPF Grade Beam Thermomass #1 Thermomass #2 Surface bonding cement

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-05-30 n/a http://www2.buildinggreen.com/blogs/choosing-foundation-materials-subconscious-decision http://www2.buildinggreen.com/ 9053 Is our approach to green building an "appropriate technology"?

Almost every technological "solution" has created a new set of problems which it was assumed would be solved by further advances in technology. How is green building different?

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts]

4. Methods – criteria for appropriate technology

If the "bricks and mortar" are the ingredients of our buildings, then the rest of the recipe is about how best to assemble, mix and "bake" those ingredients into an integrated whole that is delicious, wholesome and nourishing. As with most vocations, architecture has evolved into a professional specialization more resembling the master chef than the kitchen cook--with the emphasis more on "delicious" than on wholesome and nourishing.

Since the start of the Age of Reason (also euphemistically called The Enlightenment), we have associated "progress" with the advance of science and technology. And, as with any evolutionary progression, it became continuously more elaborate and complex – but without the harmonizing guidance of Gaia and with no comparable human oversight or vision. It became a dogma of modern life (and advertising) that "new" was always "better."

Unintended Consequences

Because of this lack of forethought and vision, almost every technological "solution" created a new set of problems which it was assumed would be solved by further advances in technology.
This is what has come to be known as the law of unintended consequences, as detailed in Edward Tenner's 1997 book Why Things Bite Back: Technology and the Revenge of Unintended Consequences. And this is precisely the problem that Einstein identified when he famously said "Problems cannot be solved by the same level of thinking which created them."

"The chief cause of problems is solutions."
– Eric Sevareid (CBS news journalist from 1939 to 1977)

Appropriate Technology

But, at the start of the environmental movement, a few visionaries challenged the dominant paradigm of "value-neutral" technology with the idea of "appropriate technology." Perhaps the simplest definition is this: appropriate technology is being mindful of what we're doing and aware of the consequences. Grounded in the village self-sufficiency philosophy of Gandhi, British economist Fritz Schumacher's book Small is Beautiful – Economics as if People Mattered (1973) was considered one of the 100 most influential books published since WWII, and he is considered the father of the appropriate technology movement. Buckminster Fuller (1895–1983), best known for his invention of the geodesic dome, is one of its more prominent practitioners. And Stewart Brand, editor of the Whole Earth Catalog, was seminal to the advancement of the movement.

A more complete definition of appropriate technology is materials and methods that are amenable to the environmental, ethical, cultural, social, political, and economic facets of the community it is intended for, that require fewer resources, are easier to maintain, and have less of a social or environmental impact. In other words, it is the simplest level of technology that can effectively achieve the intended purpose in a particular location.

Simplicity and Forbearance

Perhaps the most infamous practitioners of appropriate (or, as Schumacher called it, intermediate) technology are the Amish. While they don't completely eschew modern machines, the primary criterion these simple-living but highly successful people use to determine what is OK is whether it might disrupt the most important thing they have: family and community relationships.
 
America's premier agrarian philosopher, Wendell Berry, uses similar criteria in choosing tools:

1.    The new tool should be cheaper than the one it replaces.
2.    It should be at least as small in scale as the one it replaces.
3.    It should do work that is clearly and demonstrably better than the one it replaces.
4.    It should use less energy than the one it replaces.
5.    If possible, it should use some form of solar energy, such as that of the body.
6.    It should be repairable by a person of ordinary intelligence, provided that he or she has the necessary tools.
7.    It should be purchasable and repairable as near to home as possible.
8.    It should come from a small, privately owned shop or store that will take it back for maintenance and repair.
9.    It should not replace or disrupt anything good that already exists, and this includes family and community relationships.

Efficiency and Effectiveness

However, we builders have increasingly exported the tools and techniques of industrial manufacturing to the job site, with the assumption that speed is the same as efficiency, and that efficiency means completing more work in less time to maximize profit. To further increase building efficiency, we have outsourced some – or a lot – of the work to those very factories which we have mimicked: engineered trusses and joists, pre-fabbed foundation or wall sections, SIPs, or modular homes.

If efficiency means creating the desired output with the minimum inputs, then to match methods to goals first requires a clear delineation of the goals of a building project. It's the same with any journey: if we don't know where we're heading, then we're likely to end up there.

Alice asked the Cheshire Cat, "Which road do I take?"
"Where do you want to go?" said the cat.
"I don't know," Alice answered.
"Then" said the cat, "it doesn't matter."

If our goal is to not only build a delicious and wholesome house but also to build a sustainable world, then how we get there is at least as important as where we end up – for the means informs and determines the ends.

At an Amish barn-raising or a community building project, the rhythmic percussion of hammers and the rasping swish of handsaws are mixed with the patter of unhurried conversation. Times to refresh and enjoy social interaction are considered just as important as work time. While leadership is valued, hierarchy and power is unnecessary. Both the tools employed, the process undertaken, and the relationships maintained are based more on conviviality than on mass production.

Conviviality

In his iconoclastic 1973 book, Tools for Conviviality, priest, philosopher and social critic Ivan Illich spoke of the need to develop new instruments for the re-conquest of practical knowledge by the average citizen and tools that could be developed and maintained by a community of users. And he emphasized the importance of scale: "When an enterprise grows beyond a certain point on this scale, it first frustrates the end for which it was originally designed, and then rapidly becomes a threat to society itself."

Small-scale, local, decentralized, empowering, low-impact, appropriate to the community's goals--these qualities of a wholesome and nourishing method, process or practice are very similar to the qualities of a sound, healthy and durable material.

"Though this be madness, yet there is method in't."
– Polonius in an aside in Shakespeare's Hamlet


The full 10-part series of Robert's reflections will be as follows. Tune in next week for more:

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-05-25 n/a http://www2.buildinggreen.com/blogs/our-approach-green-building-appropriate-technology http://www2.buildinggreen.com/ 9058 Materials: The Macrobiotics of building natural, healthy and durable

 

What used to be called the "bricks and mortar," or the material building blocks, of our homes are the ingredients we use to assemble a structure which we intend (or should) to be sound, healthy and durable. But what, precisely, do we mean by those descriptors?

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts]

3. Materials – the Macrobiotics of building: natural, healthy and durable

What used to be called the "bricks and mortar," or the material building blocks, of our homes are the ingredients we use to assemble a structure which we intend (or should) to be sound, healthy and durable. But what, precisely, do we mean by those descriptors?

Safe & Sound

Structurally sound implies that it is designed, engineered and built to withstand the expected forces that will or might impinge on the home. As building codes increase in scope and complexity, we are required to plan for not only the usual gravity loads, but also wind loads and seismic motions. It's nearly impossible (or illegal) in many jurisdictions to design a house without an engineer's stamp, and it nearly takes an engineer to interpret today's exceedingly detailed prescriptive codes. This makes it all-but-impossible to perform one of the most fundamental subsistence tasks: to build one's own home. It also requires that our houses be built more rigidly and with less flexibility and resilience, which--in nature--is often the hallmark of weakness.

A Healthy Recipe?

If the materials are the ingredients of the "recipe," should we not choose our building blocks with the same care and attention to healthiness that we commonly devote to selecting the food we eat? After all, food goes rather quickly through our bodies while our home stays with us for perhaps a lifetime. Yes, it's true that our food becomes the cells of our bodies. But we also know, from the new field of Epigenetics, that the expression of our DNA--which determines how those cells are built as well as the direction of human evolution--is entirely controlled by our external environment. The DNA is merely the blueprint, while the environment (Gaia) is the architect. Given that we Americans spend 80%–90% of our lives indoors, our "external environment" has become the artificial one that contains us and, perhaps, controls us.

For almost all of human evolution on earth, we have relied on building materials sourced from the local environment. It is only since WWII that we have shifted our dependence onto artificial, petroleum-based and "engineered lumber" materials. In that tiny speck of time, we have introduced 80,000 petrochemicals into our world which never existed in nature and with which neither our bodies not any living thing have co-evolved. The blowback (unintended consequence) has been pollution of air and water, overflowing landfills (including the great Atlantic and Pacific garbage patches), and toxic wastes (including nuclear) that the earth cannot reabsorb. And all this on top of the generations of pollution and top-soil erosion and deforestation that has been the legacy of the industrial revolution.

Though a number of visionaries sounded the alarm as early as the 1970s, it is only today that we have begun to fully comprehend that our local effects have become unprecedented global challenges, including dramatic and potentially irreversible climate change and the sixth great species extinction--the first initiated by a single dominator species.

In spite of this growing understanding, most professionals in the "green" building movement continue to rationalize the use of petrochemical materials in order to save petrochemical energy, further rationalized by the belief (which I will challenge in essay #9) that it makes a house durable.

In general, however, what makes a house healthy for human habitation is the use of building blocks that come from the same environment in which we evolved and to which are bodies are attuned and acclimated. The Greeks had a useful term for this: "autochthonous," meaning indigenous, natural, arising from place. Another term that the health-minded among us might know is "macrobiotic." This is a principle of healthy eating (and living) which was brought to America from Japan by George Ohsawa and popularized by Michio Kushi. But the term was first used by Hippocrates, the father of Western Medicine in his essay "Airs, Waters, and Places" to describe people who were healthy and long-lived.

The term was used in relation to diet by influential German physician and professor of medicine (the first dean of medicine at the University of Berlin) Christoph Wilhelm Hufeland in his book The Art of Prolonging Life (1797). Hufeland understood macrobiotics as a higher level of medical philosophy based on a life force which he thought to be present in everything and most easily detected in "organic beings," where it manifests in its response to external stimuli.

But the primary principle of macrobiotics (literally, the large view of life) is that the building blocks of our bodies (our food) must come from the local environment and be used in season as the earth provides it. This principle--similarly to autochthonous living, the greater Gaian epigenetic intelligence that guides biological evolution and the "life force" of Hufeland's medicine--suggests that the building blocks of our homes should likewise arise organically from place.

Durability

The cultural monuments that I discussed in the last essay, were intended to outlast their builders and stand as memorials to future generations (some are visible from outer space). Perhaps that's appropriate for monumental structures. If we Americans move on average every seven years and routinely raze older buildings (both commercial and residential) to make way for new, and may be forced to relocate entire urban populations as the oceans rise – what is an appropriate understanding of durability? 

In terms of sustainability, a good definition is: any structure that outlives the time it takes the earth to recover from the impact of its construction. Ironically, that means that the indigenous shelters we used for most of our evolutionary history--teepees and yurts and hogans and pueblos--are the most durable, since they had negligible ecological impact and could easily be repaired or replaced. The larger and more complex we make our homes, the more long-lasting they need to be to be considered durable. Given that we are trying to reduce our impact while housing an exponentially-growing population, it's reasonable to consider that shorter-lived naturally renewable materials--such as wood and straw and clay--may be the most appropriately durable once again.

Changing Paradigm

Though the recognition is growing that we need an entirely different paradigm for living responsibly on earth--one which marries ancient wisdom with appropriate technologies of the modern age--the "green" building movement is doing little more than putting lipstick on the pig of the current dysfunctional paradigm. We are over-engineering our shelters, using building materials that are fundamentally alien to both biology and ecology, and still creating monuments to our myopia, hubris and foolishness.

"We all live by robbing nature, but our standard of living demands that the robbery shall continue...We must achieve the character and acquire the skills to live much poorer than we do.  We must waste less.  We must do more for ourselves and each other...The great obstacle is simply this: the conviction that we cannot change because we are dependent on what is wrong.  But that is the addict's excuse and we know that it will not do."
– Wendell Berry, farmer, philosopher, poet


 

The full 10-part series of Robert's reflections will be as follows. Tune in next week for more:

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-05-18 n/a http://www2.buildinggreen.com/blogs/materials-macrobiotics-building-natural-healthy-and-durable http://www2.buildinggreen.com/ 9066 Small Can Be Beautiful – Use these principles to make it work

We continue our primer on building responsibly in the post-carbon era: How do we design to honor and support nature's patterns, rather than co-opting them?

[Editor's note: Robert Riversong, a Vermont builder, continues his 10-part series of articles taking design and construction to what he sees as radical or "root" concerns. Enjoy--and please share your thoughts. – Tristan Roberts]

2. Design – elegant simplicity, the Golden Mean

In the most fundamental sense, design is how we organize our environment to meet our needs, whether those needs are functional or aesthetic or spiritual (which are often indistinct from one another). It has been suggested that human culture, and consequently human design, has shifted from a phase of dependency on nature to a period of independency from nature.

In the former phase (99.8% of our evolutionary history), we lived very gently on the land, typically meeting our basic needs as simply and lightly as possible. In the latter phase, which we call "history" or "civilization", we sought to conquer nature and use her for our own purposes, often imposing grand structures and edifices upon the land and creating our own local environment and enclosed microclimate – typically to the detriment of the natural environment and now even the global climate.

The Greening of Design

It is also becoming more widely understood, within the progressive design community, that we must now shift once again--to a phase of interdependency or partnership with our environment. This relatively recent progression, which could perhaps be dated to Earth Day 1970, can be interpreted as going from Industrial Design (readily manageable uniformity, which remains our dominant paradigm), through Efficient Design (reducing energy inputs), Green Design (non-toxic renewable elements), Integrative Design (whole systems approach), Ecological Design (collaboration between natural & built environment) to Regenerative Design (restorative & relational).

Yet even this trend and these new and more enlightened approaches to design are necessitated by our past--and still current--failure to design (and live) appropriately and sustainably within the limits of the natural environment. Thus we must now actively design towards, not only reducing our impacts, but regenerating the human/natural environmental interface and restoring the global balance that we've so fundamentally undermined.

Balance is one of the primary elements of design, along with proportion, pattern, rhythm and harmony. Balance is an intrinsic quality of design and harmony is the external manifestation that expresses a relationship to the landscape which contains it. Good design is timeless, functional, and beautiful, ideally in its elegant simplicity. Too much architecture is an expression of the designer's ego or of an idiosyncratic aesthetic.

Archetypes

Even in our monumental phase, in which the "great" societies created near-permanent landmarks to their own values--the pyramids, the walls, the temples and cathedrals, the city-scapes--there was an intentional application of universal design principles or archetypes that were gleaned from the natural world.

In the Western tradition, the Golden Proportion--found in everything from a fiddlehead, snail or pine cone to the swirl of a hurricane and the spiral of the galaxy--was manifest in the Great Pyramid, the Parthenon and DaVinci's Vitruvian Man (named after Roman architect and author of De Architectura, Marcus Vitruvius Pollio) and the Mona Lisa.

From the East, however, another ancient design tradition might better inform us as we move toward sustainability. Rather than the geometric perfection and permanence of the Greek tradition, Wabi-sabi is a Japanese world view and aesthetic centered on the acceptance of transience. It understands authentic beauty as imperfect, impermanent, and incomplete, and is based on the elements of asymmetry, asperity (roughness), simplicity, modesty, intimacy, and the mimicry of natural processes.

From an engineering point of view, "wabi" may be interpreted as the imperfect or unpredictable quality of any object, due to inherent material or design limitations; and "sabi" can be interpreted as the principle of imperfect reliability, or limited durability. We will return to these concepts in future essays.

These principles, however, are not unique to the East:

Would I a house for happiness erect,
Nature alone should be my architect,
She'd build it more convenient than great,
And doubtless in the country choose her seat


– Horace (20 BC), author of the term "golden mean"

The essential elements of appropriate design include these: functional (form follows function), elegant in its simplicity, consistent with needs but not excess, adaptable to various life stages and occupants, buildable with available materials & skills, materials and methods appropriate for the bioregion, affordable for both occupants and the world at large.

The primary determinant of construction cost, energy use and environmental impact is size. Small houses cost more per square foot but less overall, require fewer natural resources, demand less operating expense, tend to accumulate less clutter, are easier to clean and maintain, are more intimate and reduce life to its essentials.

Principles to make small work:

  • minimize circulation spaces (hallways)
  • avoid diagonal circulation paths
  • maintain an open floor plan
  • employ multi-function spaces
  • tie spaces together visually
  • separate spaces without walls
  • use thin interior (movable?) walls/dividers
  • create niches, shelves, and built-ins
  • employ views to expand small spaces
  • use varying heights, colors and textures – expansive or intimate
  • incorporate indoor/outdoor transition spaces
  • locate windows for view, ventilation & natural light

"You know you have reached perfection of design not when you have nothing more to add, but when you have nothing more to take away." - Antoine de Saint Exupéry (author of The Little Prince)

The full 10-part series of Robert's reflections will be as follows. Tune in next week for more:

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-05-04 n/a http://www2.buildinggreen.com/blogs/small-can-be-beautiful-use-these-principles-make-it-work http://www2.buildinggreen.com/ 9071 Building Context: Land, Community, and Ecology

A primer on building responsibly in the post-carbon era: How do we design and build a wholly new paradigm which enhances, rather than depletes, the web of life?

[Editor's note: We have invited Robert Riversong, a Vermont builder (see full bio below), to write a 10-part series of articles taking design and construction to what he sees as radical or "root" concerns--from philosophy to principles of hygro-thermal engineering (full list of articles below). Enjoy--and please share your thoughts. – Tristan Roberts]

1. Context – land, community & ecology

This is the first of a series of radical (as in, going to the root) reflections on the science, the philosophy and the ethics of building shelters in a post-modern pre-apocalyptic world. These will challenge the reader but also, hopefully, enlighten and enliven the dialogue about building responsibly in a post-carbon era.

In an NPR On Point conversation on religion and spirituality for the 21st century, the guest – minister and author Richard Watts – spoke of the importance of putting text in context, lest we fall into some kind of fundamentalism. In fact, he described how Christian fundamentalism is not a radical return to original teachings but a relatively modern invention (1910–1915) and a reaction against liberal scientific modernism. By limiting its focus to textual "truth", it ignores the context - both ancient scriptural and current cultural.

The "green" building movement (I have to use quotes) is also largely a reaction to the increasingly inescapable and pressing postmodern demands of resource and fossil fuel depletion coupled with consequent and expansive environmental destruction. It is rapidly generating a "scripture" of orthodox materials and methods and a few accepted "catechisms" (such as LEED and NAHBGreen) with a primary focus on saving energy and, perhaps, slowing inexorable climate change--at best, doing less harm. "Green" is hoped to become the new fundamentalism of the building trades--but is it missing the broader cultural and environmental context? Or, as the old adage went, are we missing the forest for the trees?

Environment

In the late 14th century, Geoffrey Chaucer in his Canterbury Tales invented the term "environ" from the old French for "to encircle or surround." And from his and John Milton's later poetic use of this verb, we now have a conception of an environment as a place--distinct from ourselves--that surrounds us. For most of the human journey on earth, we lived immersed in a natural or created world of which we were an integral partner. We lived within (not upon) the land, amidst (not in) community, and reciprocally dependent upon an ecology which we knew viscerally as the Web-of-Life (not the out-of-doors).

For all the manifold gifts that the objective scientific paradigm (some would call it our modern religion) has granted us, it leaves us often bereft of the intimacy with our environs that gave both soul to religion and meaning to life. That deep immersion in life also made work into craft and brought heart into both work and play--and it imbued our actions with responsibility for the "next seven generations."

Thankfully, the most comprehensive models of sustainability (a far better term than "green"), which grew from the seed of Earth Day 1970, are built upon the tri-fold foundation of ecology, economy and equity (to which we might add a fourth: ethics). And the more comprehensive perspectives on sustainable shelter place housing within the context of land and community, reweaving a holistic fabric of life.

Further Questions

Are concentrated urban or cookie-cutter suburban or scattered 10-acre rural developments sustainable? Is cluster development with conserved common land or village development more appropriate? Is private ownership of the earth ethical, equitable and sustainable or must the land, as well as the waters and the air, become – once again – a commons for us to steward and protect for the next seven generations? Is it truly economic to consider land and housing as profit-making investments rather than as the basis of human need for sustenance and as the literal ground of essential enterprise?

How does our placement of shelter on the land impact the vitality of that land? How does that placement relate to the locations of work, shopping and recreation--does it require excessive use of vehicular transport or does it encourage conviviality? Do the materials and methods we use in home-building foster local community-based and cooperative enterprise or require centralized, hierarchical, large-scale resource exploitation systems?

Are we designing and building to meet essential human needs or merely desires, fashions and an insatiable appetite for status? What is the cost--ecological, cultural, and personal--of creating magnificent and "efficient" homes that isolate us from our neighbors, our environment, our work and play, and our quest for authentic meaning?

Kahlil Gibran, from his poetic treatise on Houses, Work and Love:

And tell me...what is it you guard with fastened doors?

Have you peace...Have you remembrances...Have you beauty, that leads the heart from things fashioned of wood and stone to the holy mountain?

Tell me, have you these in your houses? Or have you only comfort, and the lust for comfort, that stealthy thing that enters the house a guest, and becomes a host, and then a master?

Tombs or Temples?

It is worth considering whether we have entombed ourselves within elaborate boxes that separate us from the life-giving environs--both social and natural. By creating ever-larger and more sophisticated containers for shelter, work, electronic entertainment and diversion, do we rob ourselves of the diurnal interplay with sun and wind and rain and dirt and other creatures that has literally shaped us into what we are? We are not only spirit embodied in earth elements, but we now know that DNA expression--evolution – is triggered by what environs us.

Does the 80%–90% of our lives spent in artificial "climate-controlled" indoor environments displace us from the source of our being, our spirit and our meaning? What is the correlation between the quest for control of our indoor climate and the out-of-control outdoor climate which threatens to destroy our species?

How can we create essential shelter without abstracting ourselves from the environs that has guided our evolution since the beginning of time and, by so doing, accelerate the destruction of the earth of which we are made and which nourished and sustained us for millennia?

If the house is indeed the "temple of the soul" as Anthony Lawlor has said, how do we make shelter building a holy undertaking? How do we manifest the sacred in material form? How do we design and build a wholly new paradigm which enhances, rather than depletes, the Web-of-Life? This should be our quest.

The full 10-part series of Robert's reflections will be as follows. Tune in next week for more:

1.    Context – land, community & ecology
2.    Design – elegant simplicity, the Golden Mean
3.    Materials – the Macrobiotics of building: natural, healthy and durable
4.    Methods – criteria for appropriate technology
5.    Foundations – it all starts here: how do we begin?
6.    Envelope – shelter from the storm, our third skin
7.    HVAC – maintaining comfort, health and homeostasis
8.    Energy & Exergy – sources and sinks
9.    Hygro-Thermal – the alchemy of mass & energy flow
10.    Capping it All Off – hat &  boots and a good sturdy coat

copyleft by Robert Riversong: may be reproduced only with attribution for non-commercial purposes

Robert Riversong has been a pioneer in super-insulated and passive solar construction, an instructor in building science and hygro-thermal engineering, a philosopher, wilderness guide and rites-of-passage facilitator. He can be reached at HouseWright (at) Ponds-Edge (dot) net. Some of his work can be seen at BuildItSolar.com (an article on his modified Larsen Truss system), GreenHomeBuilding.com (more on the Larsen Truss), GreenBuildingAdvisor.com (a case study of a Vermont home), and Transition Vermont (photos).

2011-04-27 n/a http://www2.buildinggreen.com/blogs/building-context-land-community-and-ecology http://www2.buildinggreen.com/