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Insulating a crawlspace foundation with “cripple wall” in warm climates; in Climate Zones 5+ replace the foil- or plastic-faced fiberglass batt/roll insulation with impermeable rigid insulation or closed-cell spray polyurethane foam

No Vapor Retarders on Interior Side of Air-Permeable Foundation Insulation

Vapor retarder plastic should not be installed over fibrous insulation on basement or crawlspace walls unless rigid foam or spray foam is installed directly against the concrete, behind the blanket insulation.

Vented crawlspace foundation insulated at floor joist with rigid foam.

Publication Date

Mon, 03/01/2021 - 12:00

Capillary Break Beneath Slab - Polyethylene Sheeting or Rigid Insulation over Aggregate or Sand and Geotextile Mat

Guide describing how to install a capillary break under a slab foundation using either polyethylene sheeting or rigid insulation installed over aggregate or over sand and geotextile matting.

The floor of the sealed insulated crawlspace is covered with a heavy plastic vapor-barrier sheathing that is taped at all seams and around the foundation piers to prevent water vapor from moving into the crawlspace.

Publication Date

Thu, 08/17/2023 - 12:00

Right - This crawlspace, which is insulated on the floor, has a complete vapor barrier over the floor and up the walls that is sealed at all seams and termite inspection gap at the top of the vapor retarder.

Publication Date

Sat, 01/01/2005 - 12:00

Radon Fan

Guide describing how to install a radon mitigation fan with various types of house foundations.

Moisture Control for Residential Buildings

Author(s)

Lstiburek Joseph W

Organization(s)

Building Science Corporation,

BSC,

U.S. Department of Energy,

DOE

Publication Date

September, 2020

Report providing extensive guidance on controlling moisture in building envelopes through proper selection and installation on air, water, thermal, and vapor barriers.