Insulation Between Floor Joists In Crawl Space

Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space.

Insulation between floor joists in crawl space.

However the insulation needs to be treated with a fire retardant. It is important to secure insulation and cover it with a vapor barrier in order to prevent moisture and the mold that often follows close behind. Gaps between the insulation and the floor can lead to inefficiency and heat loss. Instead install fiberglass batting between the joist bays which are the spaces between each set of floor joists.

Use caulk or foam sealant to seal the joint between the top of the crawl space wall and the sill. Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances. 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. 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.

If your space has them avoid adding insulation to the crawl space walls. This type of insulation allows for conditioned air to be introduced into the crawl space. The insulation should press right up against the floor between joists. When the basement or crawl space has vents installed insulating joist bays.

Install an air and vapor barrier over the floor and tape it to the insulation. Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates. Floor insulation for moderate climes popular reads. If the crawl space is ventilated which is ideal because it aids in the elimination of moisture then fiberglass insulation can be easily installed under the subfloor between the floor joists.

Instead of installing the foam insulation between floor joists in the crawl space the foam board is installed against the crawl space foundation walls. Where winter temperatures are extreme opt for insulating the walls and sealing off the crawl space entirely.