How to Install Foam Board Insulation in a Basement Ceiling
- 1). Measure the distance between your ceiling joists, from inside edge to inside edge. This distance should not vary between the joists.
- 2). Measure and mark a piece of foam board insulation the width of the ceiling joist and 3 feet long to make handling easier during installation.
- 3). Place a straightedge onto the lines you've drawn and cut along the lines, using the utility knife. Snap off the foam board insulation with your hands after making the cuts.
- 4). Apply construction adhesive to the back of the panel and push it against the bottom of the subfloor between the joists. Hold until it sticks.
- 5). Cut more panels and apply them until you've covered the distance from one end of the ceiling to the other. Cut the last piece to fit.
- 6). Continue onto the next set of ceiling joists and apply panels until the entire basement ceiling is covered.
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