Sealing a crawl space prevents moisture getting into the house from the ground. It is also a very effective way to reduce air infiltration, particularly around the rim joists and seams of the stem walls.
Tom’s crew has laid polyurethane liners down on the basement ground and up the stem walls. While 6-mil to 10-mil thick liners are most common, Tom is using 15-mil ones to ensure better sealing and that they do not get punctured easily, even if people walk on them. They are taped around pillars, posts and to each other for air tightness. The liners are glued to the rim joists at the top of the stem walls. Spray foam is applied to the seams between the stem wall and the rim joists.
Bridgton is known to be a high radon area. These liners also keep radon from entering the living space. Tom is installing a vent pipe system that reaches below the polyurethane. He will connect an exterior exhaust fan to the vent pipes so that any excessive radon and moisture trapped under the polyurethane can be pulled out.
Coming next: More air sealing
See also: Partnering With Green Hearted Companies and the entire From Foreclosure To Green Home series.
