How To Insulate A Basement Floor Joists

Rigid foam is affordable.

How to insulate a basement floor joists.

Cut the insulation to length using a square and sharp utility knife. If you re ready to insulate the rim joists in your basement or crawlspace you have to decide between rigid foam and spray foam. When the basement or crawl space has vents installed insulating joist bays. 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. Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances. If you have an unfinished basement you can properly insulate the rim joists in two or three hours. For walls that are perpendicular to the building s first floor joists use short lengths of batt insulation unfaced and press them against the band joist and between the joists.

Two story homes usually have another ring of rim joists above the first floor ceiling. Once the ceiling is buttoned up insulate the rim joist the floor framing around the perimeter of the house directly above the foundation wall. 4c as an alternative to floor insulation foundation walls of unvented crawl spaces. Basement insulation bonus tip 1.

Use a box cutter to cut the insulation to length. Hold the batts in place by stapling their paper faced vapor retarders to the lower edges of the joists. Be sure to seal rim joists. 4d extend insulation into joist space to reduce air flows.

Also insulate 4a any portion of the floor in a room that is cantilevered beyond the exterior wall below. Impervious insulation is always an excellent idea for basement walls but it s absolutely essential where the floor joists of the level above meets outside walls along the edges of a basement ceiling. For walls that are parallel to the joists use faced batt insulation and ensure its kraft side faces the floor above.