Ever wonder why your floors feel cold in January even after you've insulated the attic? The culprit is often the rim joist โ that band of wood sitting right where your foundation meets the floor framing. It's one of the most overlooked air-leak spots in any Northeast Arkansas home.
A typical uninsulated rim joist is just 1.5 inches of wood between your living space and outdoor temps. In Jonesboro, where January lows regularly dip into the mid-20s ยฐF, that thin barrier does almost nothing. IRC energy code (R402.1.2) requires rim joists in Climate Zone 3 โ which covers most of Arkansas โ to hit at least R-13, and closed-cell spray foam is the cleanest way to nail it in one pass.
Here's why closed-cell wins here: at 2 inches thick you're already at roughly R-13, and that same layer acts as an air and vapor barrier simultaneously. No cutting batts to fit awkward joist bays, no gaps, no moisture problems hiding behind kraft paper. Most crawl spaces and basements in the Trumann and Jonesboro area see the whole rim joist done in a morning โ typically 150โ300 board feet of foam for a standard single-story home.
Cost-wise, expect $3.50โ$5.00 per square foot installed for closed-cell on rim joists, depending on access and prep. For most homes that's a $400โ$900 job โ and customers routinely report noticing warmer floors and lower gas bills within the first heating season.
Fall is the perfect window to get this done before heating costs spike. Reply or DM us for a free estimate โ we serve Jonesboro, Trumann, Paragould, and surrounding Northeast Arkansas communities.