How To Insulate Basement Floor Joists

It s the simplest and least expensive basement area to insulate and will bring the highest return on your investment.

How to insulate basement floor joists.

Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances. Hold the batts in place by stapling their paper faced vapor retarders to the lower edges of the joists. If you re ready to insulate the rim joists in your basement or crawlspace you have to decide between rigid foam and spray foam. 4d extend insulation into joist space to reduce air flows.

Two story homes usually have another ring of rim joists above the first floor ceiling. Rim joists let in more than air. Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space. Properly insulating and air sealing rim joists band joists takes patience so most builders simply stuff in some fiberglass and walk away.

When the basement or crawl space has vents installed insulating joist bays. Here s how to insulate under a floor. If you need to insulate these rim joists it s best to hire a cellulose insulation contractor. Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates.

Spiders bugs and even mice find the rim joist an attractive place to enter the home. Cut the insulation to length using a square and sharp utility knife. Once the ceiling is buttoned up insulate the rim joist the floor framing around the perimeter of the house directly above the foundation wall. Insulating the space between the joists in a basement or crawlspace can help reduce your energy bills.

Rigid foam is affordable. It is important to also seal and insulate the top of the concrete wall where the sill plate sits. Also insulate 4a any portion of the floor in a room that is cantilevered beyond the exterior wall below. 4c as an alternative to floor insulation foundation walls of unvented crawl spaces.