We chose 2 in thick r 10 extruded polystyrene don t use expanded polystyrene which is a less effective air and moisture barrier.
Foam board insulation between floor joists.
Once the glue is dry and all the foam board insulation is installed you can seal around the foam boards with caulk.
If it you need to spread it use a brush to help cover and smooth out the glue.
Step 5 seal.
4c as an alternative to floor insulation foundation walls of unvented crawl spaces.
4d extend insulation into joist space to reduce air flows.
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.
You can insulate second floor rim joists following the same steps shown here if you happen to tear out a ceiling during remodeling.
When the basement or crawl space has vents installed insulating joist bays.
Place back between the joist and hold it in place for five seconds or for how long the instructions on the glue says.
Instead of installing the foam insulation between floor joists in the crawl space the foam board is installed against the crawl space foundation walls.
4b slab floors built directly on the ground.
Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances.