Knight Wall Continuous Insulation Rainscreen

Submitted by Web Master on Fri, 2010-12-31 10:52

Knight Wall System's GI-Girt rainscreen supports a variety of cladding option and provides continuous insulation across the exterior of steel framed buildings. Photo: Knight Wall Systems.

Happy New Year! I am going to keep the following blog fairly simple, mainly because Knight Wall Systems is interesting enough to deserve a closer inspection, so look for a more thorough follow-up product review in the Environmental Building News.

First some context...rainscreens used in non-residential buildings are typically made up of a metal framework that holds cladding away from a building's exterior weather barrier. The cladding keeps rain away from the building, and the space between the cladding and weather barrier allows any moisture that creeps in to escape. But in steel-framed buildings, the penetrations that connect the rainscreen to the building's steel frame provide a thermal bridge that transfers heat through the insulation, significantly reducing the R-value of the wall assembly. The problem is serious enough that in most climate zones ASHRAE 90.1-2007 now requires a continuous insulation barrier in steel buildings to provide that thermal break.

BG Blog ID: 
3
BG Blog URL: 
http://www.buildinggreen.com/live/index.cfm/2010/12/31/Knight-Wall-Continuous-Insulation-Rainscreen

Comments

Hi Lauren. I forwarded your q

Submitted by Brent Ehrlich on Thu, 2011-01-27 10:36.
Hi Lauren. I forwarded your question to the folks at Knight Wall Systems. I hope their response helps answer your questions. "Not being familiar with the hurricane standard for Dade County at this point, our guess is that getting approved would likely involve testing, which we would pursue. Withstanding a 135 mph wind is directly related to the attachment of the substructure, the substructure strength, cladding attachment to the substructure and cladding panel strength. We would have to calculate the wind pressures for a specific project in order to confirm how it would be detailed to meet these loads. 135 mph is definitely at the higher end of loading. The CI-Girt is meant to go onto rigid insulation. Where rigid insulation acts at the air barrier with no back-up sheathing, the system is limited by the strength of the insulation. If you placed the rigid over a sheathed wall with an air barrier, then the loading would be on the sheathing, and the loads would be limited by this structure. For example: dense glass over steel studs. "The cladding itself would influence the results of the missile test. For humidity and moisture, going over the Dow TWS system is one of the best solutions. It is vapor impermeable from front to back and can therefore accommodate interior or exterior driven vapor drive. The high thermal performance of this air, vapor, thermal and moisture system would always make it less susceptible to condensation (vapor cannot move into it from either side). Highly corrosion-resistant fasteners and metal materials such as a Galvalume are recommended in corrosive environments. "

Does this system meet the Mia

Submitted by Lauren on Sun, 2011-01-23 09:42.
Does this system meet the Miami - Dade County code for hurricane survivability? Or could they pull a permit for their installation here? Code here requires 135 mph survivability and they shoot a 2X4X8 at over 100mph at a mock-up of an install to test for survivability on new construction. Also how does this look at windows that open? And what is the batting they're using made of? Will it hold up in South Florida's ultra high humidity? I mean it steams here, literally. It rains early in the morning in summer and by noon it's 95 degrees and all the water on the ground evaporates and anything thats not hot collects condensate which turns to mildew or mold if it doesn't air out. Just a thought.

Hi Lauren. I forwarded your q

Submitted by Brent Ehrlich on Thu, 2011-01-27 10:36.
Hi Lauren. I forwarded your question to the folks at Knight Wall Systems. I hope their response helps answer your questions. "Not being familiar with the hurricane standard for Dade County at this point, our guess is that getting approved would likely involve testing, which we would pursue. Withstanding a 135 mph wind is directly related to the attachment of the substructure, the substructure strength, cladding attachment to the substructure and cladding panel strength. We would have to calculate the wind pressures for a specific project in order to confirm how it would be detailed to meet these loads. 135 mph is definitely at the higher end of loading. The CI-Girt is meant to go onto rigid insulation. Where rigid insulation acts at the air barrier with no back-up sheathing, the system is limited by the strength of the insulation. If you placed the rigid over a sheathed wall with an air barrier, then the loading would be on the sheathing, and the loads would be limited by this structure. For example: dense glass over steel studs. "The cladding itself would influence the results of the missile test. For humidity and moisture, going over the Dow TWS system is one of the best solutions. It is vapor impermeable from front to back and can therefore accommodate interior or exterior driven vapor drive. The high thermal performance of this air, vapor, thermal and moisture system would always make it less susceptible to condensation (vapor cannot move into it from either side). Highly corrosion-resistant fasteners and metal materials such as a Galvalume are recommended in corrosive environments. "

Does this system meet the Mia

Submitted by Lauren on Sun, 2011-01-23 09:42.
Does this system meet the Miami - Dade County code for hurricane survivability? Or could they pull a permit for their installation here? Code here requires 135 mph survivability and they shoot a 2X4X8 at over 100mph at a mock-up of an install to test for survivability on new construction. Also how does this look at windows that open? And what is the batting they're using made of? Will it hold up in South Florida's ultra high humidity? I mean it steams here, literally. It rains early in the morning in summer and by noon it's 95 degrees and all the water on the ground evaporates and anything thats not hot collects condensate which turns to mildew or mold if it doesn't air out. Just a thought.