Traditional wood joists are usually 2×8, 2×10 or 2×12 lumber, but modern houses often use engineered joists like trusses or I-joists because they provide better strength for less cost. Rim Joist ...

Rigid foam is the best insulation for rim joists. We chose 2-in.-thick (R-10) "extruded polystyrene." Don’t use "expanded polystyrene," which is a less effective air and moisture barrier.

Rim joists, the framing that runs around the perimeter of your home, are a major source of heat loss. You can access them via your basement or crawl space.

Five joists had pulled away from the party wall rim joist and were just hanging on by the roof boards that spanned over the top of them. At this point, our roof was stripped all the way down to the ...