How to Install Roxul Ceiling Insulation

Enter the attic with a flashlight so you can see what you are doing. Install Roxul batts in the parts of the ceiling that are farthest from your entry point first. This helps to avoid the risk of stepping on them after they are installed. Press the batt into place and be sure its edges are well seated against the sides of the joists.

Leave a space of 2 to 3 inches at the edges of the eaves to facilitate air circulation. If you cover the eave vents with insulation, you run the risk of developing moisture and condensation problems in your roof.

Cut Roxul batts to fit around vents, pipes and other obstructions. If possible, slice only part way through a batt to cover a pipe that has a smaller diameter than the thickness of the batt. This maintains the integrity of the insulation layer. Roxul can be cut with a sharp utility knife or a serrated bread knife.

Pull up slightly on the edges of a batt after you have pressed it into place. Batt insulation gains its effectiveness from the air it entraps, so don't compress it. The tops of 6-inch-thick Roxul batts should be even with the tops of 2-by-6-joists after the batts are installed.