Ever wonder why your floors feel cold in January even after you've added attic insulation? The culprit is often the rim joist โ that band of framing that sits right on top of your foundation wall. It's one of the most air-leaky spots in any home, and most Northeast Arkansas homeowners have never touched it.
A typical Jonesboro home built before 2000 has uninsulated or poorly insulated rim joists all the way around the perimeter of the basement or crawl space. Each individual bay might only be 8โ10 inches tall, but multiply that around a 1,500 SF footprint and you've got a lot of exposed wood talking directly to 28-degree January air.
The fix is straightforward. We cut 2-inch closed-cell spray foam boards or, better yet, spray 2" of closed-cell foam directly into each joist bay. Two inches of closed-cell hits R-13 and โ critically โ creates an air seal at the same time. IRC Section R402.4 actually requires air sealing in these locations for new construction in Climate Zone 4, which covers all of Craighead and Poinsett counties.
Cost-wise, expect to pay roughly $3.00๏ฟฝ๏ฟฝ$4.50 per board foot for professionally applied closed-cell foam. A typical perimeter treatment on a 1,500 SF ranch house runs 150โ220 board feet โ so a $500โ$900 project that can trim 10โ15% off your heating bill. Most customers see payback in under three winters.
If you're already scheduling a crawl space or attic job, ask us to knock out the rim joists at the same time. Bundling cuts mobilization costs and the whole perimeter usually adds only a couple of hours to the crew's day.
Reply or DM us for a free rim joist estimate โ we serve Jonesboro, Trumann, Paragould, and all of NEA.