Ever wonder why your hardwood floors feel cold in January even after you've insulated the attic? The culprit is almost always the rim joist โ the band of framing that sits right on top of your foundation wall. It's one of the most air-leaky spots in any house, and most homeowners in Jonesboro and Trumann have never touched it.
A rim joist is typically just 1.5 inches of wood with maybe a thin strip of fiberglass batt stuffed in front of it. Fiberglass slows heat transfer but does almost nothing for air movement โ and in Northeast Arkansas, where July humidity sits near 80 % and January wind chills bite hard, air infiltration is the enemy.
The fix contractors trust is closed-cell spray foam applied directly to the rim joist cavity. A 2-inch lift gives you roughly R-13, seals the air gap completely, and also acts as a Class II vapor retarder โ which matters a lot in our mixed-humid Climate Zone 3A. IRC R402.1.2 requires R-13 for above-grade wood-frame walls in Zone 3, so two inches of closed-cell checks the code box in one pass.
Cost-wise, rim joist work typically runs $1.50 โ $2.50 per board foot installed, and most standard ranch homes in this area need 60 โ 120 board feet. That puts a full rim joist job in the $200 โ $400 range โ often the highest ROI insulation project in the house relative to its size.
Homeowners who've had it done tell us the difference shows up fast: warmer floors, less mustiness from the basement or crawl, and a noticeable drop on the next Entergy bill. Small job, big payoff.
Reply below or DM us to schedule a free rim joist inspection before the next heating season sneaks up on us.