How to Install Floor Truss Insulation

Fill any gaps in the floor deck above the trusses using a foam sealant. Pay special attention to the areas where the plumbing pipes penetrate the flooring. The foam stops heat-robbing drafts.

Cover all copper plumbing pipes below the flooring with foam pipe insulation, using a knife to cut the foam insulation to size. Foam pipe insulation prevents condensation on the plumbing pipes.

Secure hanger wire between the bottoms of the floor trusses with 1-inch roofing nails, using a hammer to drive the nails. Run the hanger wires perpendicular to the floor trusses. Space the wires every 18 inches and use the nails to hold the wire to the bottom of each truss.

Put on a long-sleeve shirt, dust mask, leather work gloves and safety glasses.

Measure the length of the floor trusses using a tape measure. Transfer the length of the floor truss measurement to a roll of batt-style insulation. Cut the insulation to size with a knife.

Slip a piece of batt-style insulation over the hanger wire at one end of a set of trusses, keeping the paper liner side of the batt-style insulation facing down. Work the insulation along the length of the truss using the hanger wires between its set of trusses for support. Repeat this for each piece of floor truss insulation.

Unfold the paper line flaps -- the extra paper along each side of the woven fiberglass -- in the batt-style insulation. Position each flap under its respective floor truss.

Attach the batt-style insulation flaps to the bottom of the floor trusses using a staple gun equipped with insulation staples. Place a staple every 4 to 6 inches.