Rim Joist & Basement Insulation in Dover, OH

Rim joist and basement insulation deals with the ring of framing that sits on top of your foundation wall. In older Dover homes, and in plenty of 1970s ones, that rim joist is bare lumber with gaps at the sill, around pipes and where wires come in. Cold winter air flows through it into the basement and up through the floors. In summer, humid valley air condenses on it.

The fix

Closed-cell spray foam sprayed into each bay of the rim joist seals the gaps and insulates in one step. HomeGuide puts its R-value at about R-5 to R-7 per inch, and because it resists moisture, it does not trap damp air against the wood the way fiberglass batts do.

Basement walls

If you are finishing the basement, the walls come next. Ohio's Zone 5 table lists R-10 continuous or R-13 cavity insulation for basement walls. Closed-cell foam on the masonry reaches that, seals the wall and keeps new framing off the cold block. We check for leaks, cracks and white mineral deposits first, because foam should never cover a wall that is still taking water.

Stone and old block

Some older homes in the valley have stone or rubble foundations. Those walls can wick water, so we usually insulate the rim and sill above them and talk through drainage before covering the stone.