How to Insulate Metal Ducting in a Crawlspace
- 1). Measure the circumference of the ducting, which is the total of each side added together.
- 2). Add to the circumference an allowance for the thickness of the insulation. Six inches is the allowance for standard duct insulation that is 1 1/2 inches thick.
- 3). Cut your first piece of insulation at the above measurement. Lay it on the ground and slice through it with your utility knife for a quick, easy cut.
- 4). Wrap the insulation around the ducting with the fiberglass facing toward the ducting and the foil facing away. Pull until tight.
- 5). Tape the seam of the insulation with aluminum foil tape. Press firmly on the tape with a plastic squeegee to seal it to the foil facing.
- 6). Cut and install additional pieces of insulation until all the ducting is wrapped. Ensure all seams are taped to achieve an airtight seal.