What if we told you one of the biggest energy leaks in your Northeast Arkansas home isn't your attic โ it's a 9-inch strip of wood running around the entire perimeter of your basement? Rim joist insulation is one of the most overlooked upgrades we do, and it pays back fast.
The rim joist (also called a band joist) sits right where your floor framing meets the top of your foundation wall. It's typically uninsulated, full of small gaps, and in direct contact with outside air. On a cool October morning in Jonesboro, that zone can drop to near-outdoor temps โ and your floors and first-floor walls feel it.
We seal and insulate rim joists with 2-inch closed-cell spray foam, which delivers about R-13 in that tight space. Closed-cell is the right call here because it acts as both an air barrier and a vapor retarder โ critical when you're dealing with a concrete foundation that wicks moisture. Two inches runs most homeowners $1.50โ$2.25 per board foot installed, and a typical 1,500 SF ranch-style home might have 150โ200 linear feet of rim joist to cover.
IRC R402.2.8 actually calls out rim joists specifically โ they must meet the same R-value requirements as the surrounding wall assembly. A lot of older Trumann and Jonesboro homes were never brought up to that standard. If your house was built before 2010, there's a good chance yours hasn't been touched.
The job usually takes one technician half a day. Customers consistently tell us their floors feel warmer within the first cold snap after we finish. It's one of those small jobs with a big, immediate payoff.
Curious what your rim joists look like? Reply or DM us and we'll schedule a free look โ no pressure, just honest advice.