Basement & Rim Joist Insulation in Flint, MI

Basement and rim joist insulation fixes a problem most Flint homeowners feel but never see. The rim joist is the board that runs around the top of the foundation where the floor framing sits. In most older houses it is bare wood with gaps above and below it, and sometimes a loose fiberglass batt stuffed in. Cold outdoor air comes straight in there, cools the floor above and pulls warm air out of the house.

Why closed-cell foam

Closed-cell spray foam bonds to the wood and the top of the foundation, fills the gaps and insulates in one step. It does not soak up water or let humid basement air reach the cold wood behind it, which is a common problem with batts. HomeGuide puts spray foam on rim joists at about $2,000 to $2,500 for a typical house, and Consumers Energy has listed a rim joist rebate on its insulation page.

Basement walls

Michigan's energy code table lists R-10 continuous or R-13 in the cavity for basement walls in Zone 5. If you are finishing a basement, closed-cell foam against the concrete before framing (or foam board plus foam at the seams) keeps the drywall side warm and dry. If the walls show active water, efflorescence or cracks that move, that gets addressed before insulation. Foam does not fix a leaking foundation.

Crawl spaces and additions

Some Flint-area houses have a crawl space under an addition or a porch room. Those spaces are often vented, uninsulated and cold, which makes the room above uncomfortable. Insulating the crawl space walls and rim, covering the ground with a vapor barrier and closing the vents usually works better than batts under the floor.

We will look at your basement, measure the rim and walls and send a written price. Get a free estimate