Attic Air Sealing and Insulation

In older homes, attics may have extensive holes, cracks, and missing air barriers and insufficient insulation that allow unwanted heat loss in cold weather, heat gain in hot weather, and infiltration of contaminants year-round. Air sealing uncontrolled leaks and adding insulation between the attic and the home is one of the most cost-effective measures to improve your home’s performance. It can reduce your heating and cooling bills, improve comfort with less drafts, keep contaminants such as moisture, dust, and pests from entering your home, and reduce moisture-related durability problems.

Checklist

This U.S. Department of Energy checklist includes important specifications that can contribute to a complete and quality installation. All work shall comply with these specifications, all relevant codes and standards, and all manufacturer installation instructions. The contractor shall check each box on the checklist below and sign and date at the bottom to certify the work is completed.

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The attic shall be inspected for water leaks and moisture, structural, or pest damage. A list of all needed repairs shall be provided to the homeowner before attic work begins so remediation can be fully addressed as necessary.

The attic shall be inspected for sufficient attic ventilation (e.g., ridge vent, soffit vent). Ventilation issues shall be addressed before proceeding with attic air sealing or insulation.

If there is active knob and tube wiring present in the attic, insulation shall not be installed until wiring is replaced or properly boxed. Work shall not proceed if existing insulation is vermiculite, which may contain asbestos.

All exhaust fans shall be modified as required to vent to the outside, not into the attic.

A combustion safety test shall be performed if any natural draft combustion equipment exists in the home to ensure there no backdrafting or spillage. Any combustion safety issues shall be addressed before proceeding with attic work.

The contractor shall state whether existing insulation is to be removed or moved aside for air sealing.

All gaps, cracks, seams, and penetrations between conditioned and unconditioned space (such as gaps around lighting fixtures, HVAC duct boots, electric wiring, plumbing pipes, and flues) shall be sealed with sealants alone (e.g., caulk, foam, aerosol sealant) if the gaps are narrow enough or with rigid blocking material sealed in place with sealants, per the sealant manufacturer’s instructions. Fibrous insulation is not an air barrier and shall not be used for air sealing.

The seams where drywall attaches to the top plate at all interior and exterior walls shall be sealed from the attic side with a caulk, spray foam, or sprayer-applied sealant.

Larger gaps and openings (such as uncovered dropped soffits and openings under knee walls or at the tops of balloon-framed gable walls) shall be closed off using a solid material such as rigid foam or OSB that is sealed at the edges with caulk, sealant, or mastic.

Gaps around masonry chimneys or gas appliance vents shall be sealed with high-temperature-rated caulk or foam and insulation dams shall be constructed around them as needed using heat-safe materials in accordance with building code requirements.

Attic access panels, doors, and drop-down stairs shall be insulated with a minimum of R-10 rigid foam insulation and gasketed (not caulked) to provide a continuous air seal when closed.

All non-ICAT recessed light fixtures shall be boxed with a solid material such as drywall or rigid foam, that is sealed at all seams with a sealant such as caulk, mastic, or spray foam.

Before installing fibrous attic floor insulation, baffles shall be installed at all attic eaves adjoining vented soffits to prevent air flow through the insulation and to provide a path for ventilation air from the soffit vents to the ridge vents. The baffles shall extend at least 6 inches above the height of the attic insulation.

Continuous R-19 insulation shall be installed at attic knee walls, skylight shaft walls, vertical portions of all dropped ceilings, and any other vertical wall adjoining conditioned space.

All joints, cracks, and penetrations in the wall air barrier shall be fully sealed with caulk, foam, or equivalent.

Attic insulation shall be installed at all flat and sloped surfaces adjoining the conditioned space with less than 2% gaps, voids, and compressions and at levels that meet or exceed prescriptive levels specified by the 2012 International Energy Conservation Code.

All attic insulation shall be uniform and conform to manufacturer-specified density with attic rulers to verify full depth.

At the completion of the work, a radon test kit shall be provided to the homeowner with a recommendation to initiate a radon remediation strategy if post-retrofit radon measurements exceed EPA acceptable levels.

Tips to Sell Quality Installed Home Improvements

Home Improvement Expert is a valuable tool for organizations committed to quality installed work. The following tips help optimize the value of this tool when selling home improvements:

Trust Matters: Inform homeowners how your work conforms to this world-class expert guidance. Recommend they visit the DOE website as evidence these are indeed official best practices.

Knowledge Matters: Take advantage of the Building America Solution Center as a resource for becoming an expert on these projects.

Clarity Matters: Tell prospective clients to contrast your expert-recommended best practices with other contractors.

Value Matters: Advise prospective clients to insist other bids also include these checklists to ensure equivalent quality work.

Message Matters: Showcase on your website and marketing materials that your company uses the highest quality best practices specified on HIE Checklists.

Experiences Matter: Provide visual evidence contrasting the difference between poor and high quality work such as infrared images; pre- and post-energy bills; short and long warranties; and simple charts and graphics depicting performance advantages.

Related Guides

Information guide describing things to consider in the attic, ceiling, or roof before attempting retrofits of items including HVAC, wiring, or structural systems.