BASC Search | Building America Solution Center

Right - This unvented crawlspace is insulated along the walls and between the floor joists with 2-inch foil-faced polyisocyanurate; a termite inspection gap is visible above of the wall insulation and below the band joist.

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Right - Spray foam insulates and air-seals the stone walls of this unvented crawlspace.

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Right - This unvented crawlspace is insulated along interior walls with rigid foam and air-sealed by covering the floor with vapor retarder that is sealed to the rigid foam which is taped at the seams.

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Unvented Attic Insulation

Guide

Guide describing methods for insulating an unvented attic along the roof line.

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.

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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2021 IECC Climate Zone 1A: Unvented Flat Roof, 2x4 Wall, Monolithic Slab on Grade

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Unvented roof assembly at rake retrofitted with spray foam installed along the underside of the roof deck and extended to the rake edge to insulate and air seal the 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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New Whole-House Solutions Case Study: Insight Homes: Deep Creek, Seaford, Delaware

Case Study

Case study describing a home builder that has refined its home designs to achieve HERS scores of 49 to 56 on 40 to 70 homes per year.

Vented versus Unvented Attic

Guide

Guide describing options for insulating and air sealing at either the attic floor or along the roof line in new homes.

New Whole-House Solutions Case Study: Imagine Homes: Stillwater Ranch, San Antonio, TX

Case Study

Case study describing a new home builder that strives to address health, safety, and durability issues in a hot and humid climate.

Unvented roof assembly at eave retrofitted with rigid foam, spray foam, and taped top edge of existing house wrap or building paper

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Disaster-Resistant Roof Venting

Guide

Guide describing the installation of roof vents that are resistant to damage from high winds and entry of wind-borne rain, wildfire embers, or pests.

Attic Ventilation Fans

Information Guide

Information guide describing the use of attic ventilation fans to mechanically pull outside air through the attic in an attempt to cool the attic, control moisture, and prevent ice dams.