Ever wonder why your floors feel cold in January even after you've insulated the attic? The culprit is often the rim joist โ the band of framing that sits right on top of your foundation wall. It's one of the most overlooked air-leak points in Northeast Arkansas homes, and fixing it pays off fast.
A typical uninsulated rim joist is essentially a series of small wooden boxes open to outside air. In a 1,500 SF Jonesboro ranch-style home, that can add up to 50โ80 linear feet of exposed framing, each bay leaking conditioned air straight to the outdoors. No wonder October gas bills start climbing before the real cold even hits.
The fix contractors like us use: two-component closed-cell spray foam, applied at 2 inches thick right into each joist bay. At 2", closed-cell hits roughly R-13, seals the air gap completely, and adds a small amount of structural rigidity to the rim board. IRC R402.1.2 actually calls out rim joists as a required insulation location in Climate Zone 3 โ which covers Craighead, Poinsett, and most of Northeast Arkansas.
Material cost for closed-cell foam runs about $1.50โ$2.25 per board foot installed, and a typical rim joist job on a single-story home takes a half-day crew. Most homeowners spend $400โ$900 total โ and many report noticeably warmer floors and a measurable drop in heating costs by Thanksgiving.
If you're already planning a crawl space encapsulation or attic upgrade, bundle the rim joist work in the same trip. You'll save on mobilization and the payback timeline gets even shorter.
Reply here or DM us for a free rim joist estimate before the fall cool-down hits Trumann and Jonesboro.