BASC Search | Building America Solution Center

Building in Extreme Cold, BSI-031

Reference

Article describing the control layers (air, thermal, and vapor barriers) needed to build homes successfully in very cold locations.

New Code Options for Insulating, Sealing, and Controlling Moisture in Unvented Attics in Residential Buildings

Presentation

Webinar explaining new code options for insulating, sealing, and controlling moisture in unvented attics in residential buildings.

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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A typical Las Vegas hot-dry climate home made of wood frame construction and insulated with R-25 expanded polystyrene externally over a drainage plane, with an unvented wood frame insulated attic and roof assembly.

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Installation of Cavity Insulation, Info-501

Reference

Article explaining installing cavity insulation.

No Sweat, BSI-094

Reference

Guide providing information on controlling attic ductwork sweating.

Ice Dams, BSD-135

Reference

Article outlining the casuses and solutions for ice dam problems.

Zeroing In, BSI-081

Reference

Report describing Net Zero house design with sloped roof assemblies.

Hybrid Assemblies, BSI-100

Reference

Article describing issues with condensation in unvented attics insulated with open-cell spray foam.

Venting Vapor, BSI-088

Reference

Guide providing information on controlling attic ductwork sweating.

Ping Pong Water and The Chemical Engineer, BSI-016

Reference

Article outlining moisture accumulation in open cell spray polyurethane foam.

Vented roof assembly at rake retrofitted with spray foam and additional insulation installed at the attic floor and extended to the rake edge

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Cool Hand Luke Meets Attics, BSI-077

Reference

Article describing the difference between conditioned or unvented attics and unconditioned or vented attics.

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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Seal all drywall-to-top plate seams and penetrations at the attic floor

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Attic or Roof? An Evaluation of Two Advanced Weatherization Packages, BA-1205

Reference

Report about a project that examines implementation of advanced retrofit measures in the context of a large-scale weatherization program and the archetypal Chicago, Illinois, brick bungalow.

Retrofit an existing roof by installing rigid foam, new moisture and air control layers, new sheathing, and new cladding plus cavity insulation in the roof rafters to create an unvented attic

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Sloped roof with cavity spray foam insulation, strapping, and gypsum board thermal barrier

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Batt insulation is installed in two layers in perpendicular directions against the baffle to full required insulation height

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Batt insulation is installed in two layers with offset seams against the baffle to full code-required insulation height

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Westford House, BSI-018

Reference

Report describing sloped roof assemblies with high levels of thermal performance.

De-Icing Ice Dams, BSI-097

Reference

Article describing the importance of air sealing, insulation, and roof ventilation in reducing the likelihood of ice dam formation on roofs in cold snowy climates.

Flat roof with cavity spray foam plus loose-fill insulation and gypsum board thermal barrier.

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Clean the attic floor of debris prior to installing new attic insulation. Use baffles to provide a path for ventilation air entering the attic from the soffit vents

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Sloped roof with cavity spray foam insulation sprayed on underside of roof deck and covered with sprayed-on thermal or ignition barrier coating.

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Seal the drywall to top-plate seams and the lower edge of baffles to the top plate to prevent the air coming from soffit vents from flowing under baffles into insulation.

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To reduce the risk of condensation on the interior of the roof sheathing in cold weather, the ratio of exterior (above-deck) insulation must be increased as a percent of total attic insulation as outside temperature decreases

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Wrong: Closed-cell spray foam roof insulation was not thick enough to meet IRC levels so the foam surface is colder than the dew point of the interior air and condensation formed on surface of the foam

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Blown Insulation for Existing Vented Attic

Guide

Guide describing how to insulate a vented attic in an existing home using blown insulation added to the attic floor.

Below Deck Spray Foam Insulation for Existing Roofs

Guide

Guide describing how to add spray foam insulation to the underside of the existing roof deck as part of the conversion of a vented attic to an unvented, insulated attic.