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Attic Eave Minimum Insulation

Guide

Guide providing guidance on insulating attic eaves in new and existing single-family homes and multifamily buildings.

Unvented Insulated Sloped Roofs

Guide

Guide describing construction of unvented, sloped, insulated roof assemblies in high wind zone areas.

The Truth about insulation in a hot climate

Video

Video from Horizon Energy on thermodynamics relating to insulation in attics of homes located in hot climates.

Detail of an unvented cathedralized attic showing air-impermeable spray foam insulation plus batt insulation installed on the underside of the roof deck.

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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.

Right – Baffles maintain air flow above attic insulation

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Right - Spray foam insulation has been sprayed onto the underside of the sloped roof and the gable end wall to provide a sealed, insulated attic for housing the HVAC ducts

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Air Sealing, Insulating, and Venting Attics and Roofs to Reduce Heat Gain

Information Guide

Information guide providing links to guides describing specific ways to air-seal, insulate, and ventilate attics and roofs to minimize heat gain in new and existing homes.

Application of Spray Foam Insulation Under Plywood and OSB Roof Sheathing

Video

Video describing how to air seal attic rafters with spray foam.

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

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Air-Impermeable Insulation for Condensation Control in Unvented Attics, per IRC Table 806.5.

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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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Examples of many common ceiling penetrations that will be difficult to insulate and air seal in this cathedral ceiling.

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Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing, BA-1312

Reference

Report covering moisture and leakage issues associated with spray foam insulation application to the underside of roof sheathing.

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

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Spray foam insulation was installed on the underside of the roof deck and on gable end attic walls to create an unvented attic

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The soffit dam and baffle allow air to flow through the vents without disturbing the insulation covering the top plates

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Right - These raised heel roof trusses provide 16 inches of space over the outer walls for full insulation coverage at the attic perimeter.

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Right – Sheathing extends to rafters adding strength to soffit, baffles keep attic insulation from vent to maintain air flow

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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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Right - This new sealed attic has 5.5 inches (R-20) of spray foam insulation along the underside of the roof deck providing a conditioned attic space for the heating and cooling ducts.

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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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Wrong – Roof underlayment is not fully adhered and roof deck seams are not sealed so roof is susceptible to high-wind events

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Right – Roof underlayment is fully adhered and roof deck seams are sealed so roof is resistant to high-wind events

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Attic Eave Minimum Insulation

Unvented Insulated Sloped Roofs

The Truth about insulation in a hot climate

Detail of an unvented cathedralized attic showing air-impermeable spray foam insulation plus batt insulation installed on the underside of the roof deck.

Below Deck Spray Foam Insulation for Existing Roofs

Right – Baffles maintain air flow above attic insulation

Right - Spray foam insulation has been sprayed onto the underside of the sloped roof and the gable end wall to provide a sealed, insulated attic for housing the HVAC ducts

Air Sealing, Insulating, and Venting Attics and Roofs to Reduce Heat Gain

Application of Spray Foam Insulation Under Plywood and OSB Roof Sheathing

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

Air-Impermeable Insulation for Condensation Control in Unvented Attics, per IRC Table 806.5.

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.

Examples of many common ceiling penetrations that will be difficult to insulate and air seal in this cathedral ceiling.

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing, BA-1312

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

Spray foam insulation was installed on the underside of the roof deck and on gable end attic walls to create an unvented attic

The soffit dam and baffle allow air to flow through the vents without disturbing the insulation covering the top plates

Right - These raised heel roof trusses provide 16 inches of space over the outer walls for full insulation coverage at the attic perimeter.

Right – Sheathing extends to rafters adding strength to soffit, baffles keep attic insulation from vent to maintain air flow

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

Right - This new sealed attic has 5.5 inches (R-20) of spray foam insulation along the underside of the roof deck providing a conditioned attic space for the heating and cooling ducts.

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

Attic Knee Walls

Condensation Control in Attics and Roofs in Cold Weather

Hybrid Assemblies, BSI-100

De-Icing Ice Dams, BSI-097

Air Sealing Drywall to Top Plate

How to Prevent Roof Damage from Winter Ice Buildup

Wrong – Roof underlayment is not fully adhered and roof deck seams are not sealed so roof is susceptible to high-wind events

Right – Roof underlayment is fully adhered and roof deck seams are sealed so roof is resistant to high-wind events