4d extend insulation into joist space to reduce air flows.
Foam board insulation between floor joists.
Step 5 seal.
Place back between the joist and hold it in place for five seconds or for how long the instructions on the glue says.
Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances.
Rigid foam is the best insulation for rim joists.
You want it snug but not to.
4b slab floors built directly on the ground.
We chose 2 in thick r 10 extruded polystyrene don t use expanded polystyrene which is a less effective air and moisture barrier.
If it you need to spread it use a brush to help cover and smooth out the glue.
When the basement or crawl space has vents installed insulating joist bays.
Also insulate 4a any portion of the floor in a room that is cantilevered beyond the exterior wall below.
Unlike fiberglass rigid foam insulation does not absorb water support mold or allow air to pass through.
The best insulation material for crawl spaces is rigid foam insulation board.
You can insulate second floor rim joists following the same steps shown here if you happen to tear out a ceiling during remodeling.