What Insulation To Use In Floor Joists

Turn off the electricity then remove an electrical outlet cover for a view of exterior insulation.

What insulation to use in floor joists. Check between floor joists if vented and check perimeter walls if unvented. Exterior walls and floors. The insulation should be long enough to hang from the sill above the wall butting against the insulation you installed in step 2 above and extend 2 feet onto the crawlspace floor.

Instead of installing the foam insulation between floor joists in the crawl space the foam board is installed against the crawl space foundation walls. Insulation also helps to preserve the air quality and reduce energy costs. Two by eight floor joists two by eight joists actually measure 7 1 4 inches by 1 1.

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. The goal however is the same.

Use a box cutter to cut the insulation to length. There are two types of crawl spaces ventilated and unventilated and each requires its own form of insulation. Cut the insulation to cover the walls at the end of the floor joists.

Properly insulating and air sealing rim joists band joists takes patience so most builders simply stuff in some fiberglass and walk away. To enclose the space in a thermal envelope. Ground should be covered with a 6 mil polyethylene sheet.

Without insulation heat and cool air are easily lost through the floor. 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. Insulation depends on loft however so stuffing too large a batt in a joist space will reduce its effectiveness.