How to finish a basement.
Rigid insulation between floor joists.
When the basement or crawl space has vents installed insulating joist bays.
The fiberglass will also need to be secured in place using wire mesh twine wood laths or other securing methods which can be an intensive project that adds to the overall cost.
Seal and insulate using rigid foam board insulation.
Fill gaps larger than 1 4 in.
Unlike fiberglass rigid foam insulation does not absorb water support mold or allow air to pass through providing that joints between boards are sealed with tape.
Run a bead of acrylic caulk around each section of foam to form an airtight barrier.
A do it yourself friendly method for sealing and insulating the rim joist or band joist area is to use rigid foam up against the rim joist.
Gaps between the insulation and the floor can lead to inefficiency and heat loss.
The insulation should press right up against the floor between joists.
This method can be hundreds of dollar less than the cost of using the commercially applied spray foam.
Cut rigid foam insulation into strips with a table saw or a circular saw.