How To Insulate Floor Joist Pockets

In better insulated situations these cavities are partially filled with high density foam or extruded foam pieces.

How to insulate floor joist pockets.

Quite often basement perimeter foundation walls are framed insulated and covered with 6mil poly to the underside of the floor joists and loosely stapled in place between these pockets. Use a box cutter to cut the insulation to length. Properly insulating and air sealing rim joists band joists takes patience so most builders simply stuff in some fiberglass and walk away. Insulating rim joists pockets.

If the foam board is properly sealed additional fiberglass. The pockets between the joists were not insulated. At the rim joist area many building components come together the foundation wall the mudsill the rim joist the subfloor so it s also important to seal all cracks against air leakage. This may be a bit long so bear with me.

I filled the pockets with insulation 2 pieces of fibreglass to total 5 5 inches thick then sealed the pockets with a piece of polyethylene. In cold humid or mixed climates the foam board thickness needs to be 2 thick to stop the condensation in the rim joist area. Have work shop and family room downstairs it seems to get chilly after. If you have an unfinished basement you can properly insulate the rim joists in two or three hours.

Rim joists are above grade so it makes sense to insulate the joists to the same level as above grade walls. On one side of my house where the joist runs parallel to the outside wall i insulated and put poly part way only but could not seal it because of a. We have a ranch with a full basement and craw space. This is an effective method for air sealing this area while still being easy on the pocket book.

A merry christmas to everyone.