Most Arkansas homeowners don't even know what rim joists are, but they're often the biggest energy leak in your house. These are the boards that sit on top of your foundation wall where your floor meets the exterior wall.
In Northeast Arkansas homes, uninsulated rim joists can account for 15-20% of total air leakage. That's like leaving a window cracked open year-round. With our humid summers starting early this year, sealing these gaps becomes even more critical for comfort and mold prevention.
The best solution? Closed-cell spray foam applied directly to the rim joist cavity. Unlike fiberglass batts that leave gaps, spray foam creates an air seal while providing R-6 to R-7 per inch. For our climate zone 3A, you want at least R-13 in rim joists — that's about 2 inches of closed-cell foam.
DIY rim joist sealing with canned foam rarely works long-term. The foam shrinks, gaps reopen, and moisture finds its way in. Professional spray foam application costs around $3-5 per square foot but typically pays for itself within 3-4 years through lower utility bills.
If you're in a crawl space home around Jonesboro or Trumann, rim joist insulation should be your first priority before tackling walls or attic space. It's the foundation of a properly sealed building envelope.
Thinking about tackling those rim joists before the summer heat peaks? Reply or DM us for a free estimate on professional spray foam application.