Should You Insulate Floor Joists In Basement

4c as an alternative to floor insulation foundation walls of unvented crawl spaces.

Should you insulate floor joists in basement.

Also insulate 4a any portion of the floor in a room that is cantilevered beyond the exterior wall below. Basement insulation bonus tip 1. The insulation should extend all the way down to the basement floor or at least to below the frost line the depth to which the ground freezes in winter. If you have an unvented crawlspace or basement you must insulate the walls instead of the floor joists.

Cut pieces of insulation just large enough to fit along the rim joist the framing material into which all the floor joists are nailed. To prevent these problems only air impermeable insulation either rigid foam or spray polyurethane foam should be used to insulate the interior of a rim joist. When you re using fiberglass batting insulation material run it about 6 inches or so onto the crawl space floor. Two story homes usually have another ring of rim joists above the first floor ceiling.

Hold the batts in place by stapling their paper faced vapor retarders to the lower edges of the joists. Check out the guide to insulating basement walls link above. Jerry thanks for the comment getting back to you after the holidays. 4d extend insulation into joist space to reduce air flows.

If you need to insulate these rim joists it s best to hire a cellulose insulation contractor. When insulating basement walls don t forget the band joist the piece of wood at the top of the wall that extends around the perimeter and encloses the ends of the floor joists. First you ll have to maneuver batts of insulation around the clutter of wires pipes and cross bracing in a typical basement ceiling. 2 xps foam board against in my case board formed concrete framed up with 2 4 studs with a composite board under the bottom plate as a capillary break.

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. I have an almost identical installation in my home basement. Be sure to seal rim joists. Lay down a moisture barrier with sheets of 6 mil plastic if you have a dirt or gravel floor.

Properly insulating and air sealing rim joists band joists takes patience so most builders simply stuff in some fiberglass and walk away. 4b slab floors built directly on the ground. This will also block tiny passages where spiders and other insects enter your basement.