BASC Search | Building America Solution Center

Vented roof assembly at eave retrofitted with rigid foam, spray foam, and fully adhered membrane to air seal the top of wall-to-roof transition

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Steel angles for supporting brick veneer are offset from the concrete floor slabs of a multistory building by standoffs to reduce thermal bridging and allow room for rigid exterior insulation between the steel angles and the slab edges

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This basement is insulated on the exterior with rigid foam over dampproofing, with granular backfill and footing drains to facilitate drainage away from the foundation, a termite shield to protect from pests, and cellular PVC to protect the rigid foam.

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Masonry wall interior retrofit with parge coat, fluid-applied water control layer, mineral wool rigid foam, and wood or metal stud service cavity (climate zones 1-4 only)

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Right – This builder installs 1 inch of XPS rigid foam on the exterior of the 2x6 walls then covers the foam with ½-inch plywood sheathing, which serves as a nailing surface for siding and trim.

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Capillary break at all crawlspace floors using ≥ 6 mil polyethylene sheeting, lapped 6-12 in., and lapped up each wall or pier and fastened with furring strips or equivalent

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The basement is constructed with precast concrete walls lined with R-21.3 foil-faced rigid foam while an R-10 layer of XPS rigid foam covers the ground under the slab.

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These factory-built walls consist of 9.5-inch I-studs sheathed with coated OSB, faced with OSB, and dense-packed with cellulose; a second interior surface of drywall is added to provide a 1.5-inch cavity for electrical wiring.

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The OSB roof decking product comes with an adhered radiant foil barrier which helps to prevent heat transfer in or out of the vented attic, while R-13 unfaced fiberglass fills the advanced-framed 2x6 walls.

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Completed wall retrofit of masonry home (on right) showing new lap siding attached over four inches of rigid foam; windows were boxed with plywood to accommodate depth of foam plus 1x4 furring strips

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The Larsen-truss 9-inch wall cavities were covered with a smart vapor membrane that was fastened to the trusses with furring strips, which also provide an air gap behind the wood siding; each truss cavity is then filled with blown cellulose.

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A 1- and ½-story home with a room located in the attic and the thermal boundary located at either a) the walls and ceiling of the attic room with small vented attic spaces or b) the roof line for an unvented attic

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Unvented roof assembly at rake retrofitted with a filler piece and taped top edge of existing house wrap or building paper to seal the top of wall-to-roof transition

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Drywall was removed and the existing 2x4 walls were filled with 3.5 inches of dense-packed cellulose. Outside, the ½-inch plywood was topped with house wrap, 1.5 inches closed-cell rigid foam, 1x3 furring strips, and fiber cement siding.

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Right – A 1-inch layer of XPS rigid foam covers the 2x6 wall studs and is topped by ½-inch-thick plywood sheathing, which is covered with draining house wrap and serves as a nailing surface for siding and trim.

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The builder installed 1.5 inches of soy-based spray foam on the outside of the walls over the OSB sheathing, then kept a ¾ inch gap between the foam and the brick veneer siding to allow moisture vapor from the bricks to dissipate.

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Rigid foam provides intermittent thermal breaks in a continuous slab floor with triple-pane-glass exterior wall panels in this multistory, multifamily building; stainless steel rebar provides structural support through the thermal break

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These prefabricated rebar assemblies use stainless steel and rigid foam to provide a thermal break where a concrete floor slab passes through the exterior wall of a multistory building; the stainless steel is connected to carbon steel rebar

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Right – R-23 of blown fiberglass fills the walls and unvented vaulted attic cavities of this marine-climate home while an additional R-20 (4-inches) of graphite-enhanced expanded polystyrene is installed above the roof sheathing.

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After setting precast concrete basement walls on an 8-inch bed of trap rock, this builder sprayed 2 inches of closed-cell spray foam directly onto the ground then laid piping for radiant floor heating before pouring the concrete floor slab.

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Reducing Thermal Bridging in Mass and Steel-Framed Multifamily Buildings

Guide

Guide describing common areas of thermal bridging in mass (concrete) and steel-framed multistory buildings and methods and materials for addressing those points of thermal bridging.

Advanced Framing vs Traditional Framing

Video

Video describing traditional 2x4 16 inch on center framing versus advanced framing with 2x6 stud walls at 24 inch on center, insulated corners and headers, wall stud-ceiling joist alignment, etc. providing a strong wall with more room for insulation.

Lay out the rigid foam sheathing joints so they do not align with the window and door edges

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Dropped Ceiling/Soffit Below Unconditioned Attic

Guide

Guide describing how to insulate and air-seal dropped ceilings and soffits to prevent air leakage.

Builders Challenge High Performance Builder Spotlight: David Weekley Homes, Houston, Texas

Case Study

Case study describing new home construction in the hot-humid climate, optimizing thermal enclosure, HVAC, water heating and lighting measures.

High Performance Builder Spotlight: Scott Homes Inc.

Case Study

Case study describing a new home construction project in the marine climate.

2-stud corner with 1x4 backer

CAD File

Wind Washing

Guide

Guide describing wind washing of insulation in the eaves of vented attics and how to prevent it.

2-stud corner with drywall clips

CAD File

Technology Solutions Case Study: Stand-Off Furring in Deep Energy Retrofits

Case Study

Case study describing a stand-off furring strategy that minimizes the physical connections to each existing wall stud, uses spray foam to encapsulate existing siding materials (including lead paint), and creates a vented rain screen assembly to promote drying.