How To Install Insulation In Floor Joists

If the crawl space is ventilated which is ideal because it aids in the elimination of moisture then fiberglass insulation can be easily installed under the subfloor between the floor joists.

How to install insulation in floor joists.

The sill plate is the first piece of framing lumber and it runs on top of the crawl space wall. If the insulation is too wide for the space cut it. When you re using fiberglass batting insulation material run it about 6 inches or so onto the crawl space floor. Paper facing provides a moisture barrier and is always placed facing the space that is warmer in.

In crawlspaces and basements make sure there are no cracks in the foundation. Fit the insulation pieces into the joist bay with the paper facing up toward the living space. Cut pieces of insulation just large enough to fit along the rim joist the framing material into which all the floor joists are nailed. 4c as an alternative to floor insulation foundation walls of unvented crawl spaces.

Cover the walls with insulation from the sill plate to the plastic covered dirt floor. Install the insulation with the paper vapor barrier facing up toward the heated living space and make sure the insulation fits tightly between the joists. 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. Install the insulation with the vapor barrier facing up toward the heated living area of the house.

4b slab floors built directly on the ground. Start at one end of the floor joist where it joins the vertical support wall. Hold the insulation in place from below using insulation support wires or by stapling chicken wire to the bottom of the 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. If you re insulating framed walls make sure the insulation is the correct thickness for your wall studs.