Rim joists and band joists
Rim joists: where the cold gets in
The rim joist and sill plate sit right where the house meets the foundation, and a lot of cold air finds its way in there. We seal them with closed cell foam, usually along with a crawl space or basement job.
Or text a photo to 740-590-5352.
What we do
Closed cell spray foam goes into each bay of the rim joist and over the sill plate. One layer insulates and fills the cracks and gaps that let air in. In a basement, it goes behind where shelving and outlets usually end up, so it is worth doing before a finish.
The Department of Energy says air can leak through multiple seams and holes where the rim joist meets the wall, the sill plate, and the subfloor
, and that the best moisture control is achieved by filling the cavities where the floor joists meet the rim joist with spray foam insulation
[1].
What homeowners tell us
Coreland had rooms over a crawl space running about 10 degrees cooler than the rest of the house. After the crawl space and rim joists, he says the variation dropped by 50 to 60%.
“The rooms above the crawl space were consistently 10 degrees cooler in the winter than the rest of the house. This has dropped that variation by 50-60%.”
Coreland · crawl space and rim joists · Google review
Customer videoRim joists and sill plates
A homeowner walks through the rim joists and sill plates we sealed, and what changed in the house afterward.
Watch on YouTube
Blower door testMeasured, not guessed
A blower door pulls air out of the house and measures how much leaks back in, in CFM50. Here is the test on a house we finished with closed cell spray foam.
Watch on YouTubeQuestions about this job
What is a rim joist?
The band of framing that sits on top of the foundation wall and caps the ends of the floor joists. It is also called the band joist. The sill plate is the board under it that sits on the foundation.
Why seal it?
It is thin wood with a lot of edges and gaps, right at the outside of the house. The Department of Energy says air can leak through multiple seams and holes where the rim joist meets the wall, the sill plate, and the subfloor
, and that the best moisture control is achieved by filling the cavities where the floor joists meet the rim joist with spray foam insulation
[1].
Do you do it with spray foam?
Usually closed cell spray foam, which insulates and seals the gaps in one layer. We often do it along with a crawl space or basement job.
Get a price
Tell us about the job
A few details and a photo or two is all it takes. We call you back to set up a time to come out, measure, and give you one written price for the whole job.
Sources
- U.S. Department of Energy, Building America (PNNL and ORNL). Energy Renovations: Insulation, A Guide for Contractors to Share with Homeowners (2012).