Feel a cold breeze near your baseboards every January? 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 under-insulated spots in Northeast Arkansas homes, and it leaks conditioned air year-round.
So what does rim joist insulation cost per square foot? For closed-cell spray foam โ the right tool for this job โ expect $1.50โ$2.50 per board foot installed. Most crawl spaces and basements in the Jonesboro/Trumann area need 2 inches of closed-cell foam on the rim joist, which hits R-13. IRC R402.1.2 actually requires R-13 minimum for this assembly in Climate Zone 3, so you're meeting code and sealing air in one shot.
Why closed-cell and not batts? Fiberglass batts can be stuffed in there, but they don't air-seal โ they just slow conduction while convection keeps driving your energy bill up. Two inches of closed-cell foam bonds directly to the wood, stops moisture vapor (critical in our humid Arkansas summers), and delivers a Class II vapor retarder without any add-ons.
A typical 1,500 SF ranch house might have 150โ200 linear feet of rim joist. At 8 inches tall, that's roughly 100โ135 SF of surface. Total material-and-labor investment: $300โ$600 in most cases. Homeowners regularly report 10โ15% drops in heating and cooling costs after this one fix alone.
It's a small job with a fast payback โ and a great thing to knock out right now before the October cool-down hits the Arkansas Delta.
Reply here or DM us for a free rim joist estimate. We serve Jonesboro, Trumann, Paragould, and surrounding communities.