Ever wonder why your floors feel cold even after you've insulated the attic? The culprit is often the rim joist โ that band of wood sitting right at your foundation line where the floor framing meets the foundation wall. It's one of the most air-leaky spots in any house, and in Northeast Arkansas winters, that gap works against you every single day from November through February.
So what is rim joist insulation, exactly? It's the process of sealing and insulating each joist bay along the perimeter of your basement or crawl space. Most contractors use 2-inch closed-cell spray foam, which hits roughly R-13 in one pass and โ more importantly โ air-seals at the same time. Air sealing is the part blown-in insulation can't do on its own.
Here's the math that makes it worth it. A typical 1,500 SF ranch home has roughly 120โ160 linear feet of rim joist. At about $3.50โ$4.50 per board foot and a 2-inch application, most jobs run $600โ$1,100 total. Homeowners commonly report a 10โ15% drop in heating bills the first winter โ real money when a Jonesboro gas bill can spike past $200 in January.
IRC Section R402.4 calls out rim joists as a required air-barrier location in Climate Zone 3 (that's us). So if your home was built before the 2012 energy codes tightened up, there's a good chance your rim joist is bare wood or stuffed with old fiberglass batts that have sagged and left gaps.
The job usually takes a crew about two to three hours. It's fast, it's affordable, and it makes an immediate, measurable difference โ especially heading into fall. Don't wait until your heating bill reminds you.
Reply or DM us for a free estimate on rim joist spray foam. We serve Jonesboro, Trumann, Paragould, and surrounding Northeast Arkansas communities.