Tags: #architecture #buildingdesign #buildingenclosures #buildingenvelopes #buildingmaterials #buildingproducts #buildingscience #fasteners #materialsscience

Three concepts visualized in terms of their bridging elements and their impacts on thermal performance.

I’ve hidden the remaining components such as sheathing, insulation, and interior gypsum. Although not plotted to the same temperature scale, we can still gain an appreciation for the relative effects of each strategy. Traverse a batt-filled cavity with steel studs and it’s easy to see how effective R-values are reduced by more than 50%.  Likewise, little improvement is offered by metal girts that span exterior insulation. Yet, the R-12 wall persists – a product of flawed logic – of making cladding ATTACHMENT systems into cladding FASTENER systems; and conveniently excluding them from our conscious thought. 

Many approaches exist to achieve the intent of the code, including nail base systems and Structural Insulated Sheathing – as show here (C). In this approach, the bridging element is reduced to fasteners spaced twelve inches on center. We achieve the R-21 wall from the same three-inch profile as the R-12 wall.