Seal and insulate crawl space

Think of it as a mini-basement
Air and thermal barriers should be complete and continuous. They should be attached either to the underside of the floor joists or along the exterior foundation walls–from footing to band joist. Insulating and air sealing at floor level is difficult due to the pipes, wires and utilities that pass through it. For this reason, it’s best if the crawl space is unvented and conditioned–especially if HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. ducts are present. A vapor barrier along the ground with a thin concrete slab on top also reduces water vapor and soil gas. Under most circumstances, a crawl space designed just like a full basement foundation, only shorter, is the best course.

Protect insulation from insect and moisture damage. In locations with termites, provide a termite barrier to prevent insulation from being used as a pathway for termite infestation.

Basement Wall Insulation Values:
Climate Zones 1 & 2: 0
Climate Zones 3, 4, & 5: R-13
Climate Zone 6: R-13
Climate Zone 7 & 8: R-21

Green points

NGBSNational Green Building Standard Based on the NAHB Model Green Home Building Guidelines and passed through ANSI. This standard can be applied to both new homes, remodeling projects, and additions. /ICC-700: In an insulated crawl space, permanently attaching insulation to the walls is mandatory. Exposed earth must be covered with a vapor retarder (701.4.4.2).

Learn more in the Green Building Encyclopedia

Crawl Spaces

Learn more in the Construction Detail Library

Construction Details: Concrete crawl spaces

Further Resources

Building Science Corp.
Crawlspace Insulation

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