BASC Search | Building America Solution Center

Air Sealed, Insulated Basements

Guide

Guide describing how to insulate a basement to improve the overall thermal performance of the building and provide more dry, usable conditioned space for home occupants and HVAC equipment.

Wrong - This batt insulation is not aligned with the subfloor and joists.

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This exterior insulated slab-on-grade monolithic grade beam foundation is protected from pests by termite shield at the sill plate, borate-treated framing, flashing at end of wall insulation, brick veneer over slab-edge insulation, and rock ground cover.

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Wrong - Sub-floor insulation is not properly installed or supported.

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Right - Sub-floor insulation is properly installed and supported.

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Wrong - Sub-floor insulation has gaps, compression, and misalignment.

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Exterior XPS basement insulation is correctly installed to completely cover the foundation wall

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Air seal the floor above an unconditioned basement or crawlspace and make sure floor insulation is in full contact with the underside of the subfloor.

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Foil-faced rigid foam and spray foam can be used to insulate a basement on the interior; use good moisture management techniques to keep the basement dry

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Exterior fiberglass insulation on this new home was (incorrectly) cut to terminate below-grade after backfill, which will expose the above-grade portions of the foundation wall to cold temperatures

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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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Floor Above Unconditioned Basement or Vented Crawlspace

Guide

Guide describing how to air-seal and insulate the floor above an unconditioned basement or crawl space.

Increase Seismic Resistance and Thermal Performance of Basement, Crawl Space, and Crawl Space with Cripple Wall Foundations

Guide

Guide describing different options for providing seismic and thermal resistance for homes with basement foundations, crawlspace foundations, or crawlspace foundations with a "cripple" wall.

DOE ZERH HIA 2017 Case Study: Thrive Home Builders, Courtyard Rows, Lone Tree, CO

Case Study

Case study describing a DOE Zero Energy Ready Home 2017 Housing Innovation Award winner that scored HERS 41 without PV and 8 with PV.

DOE ZERH HIA 2013 Case Study: Preferred Builders, Old Greenwich, Connecticut

Case Study

Case study describing a DOE Zero Energy Ready Home 2013 Housing Innovation Award Winner in Old Greenwich CT, that scored HERS 42 without PV and HERS 20 with PV.