Fiberglass Insulation Roof Rafters

Although many builders have installed fiberglass batt insulation between attic rafters to insulate cathedral ceilings and attic roofs this technique isn t as effective as more modern methods of roof insulation.

Fiberglass insulation roof rafters.

Vented attics have insulation installed underneath the roof deck in direct contact with the decking. R 30c and r 38c are available in both kraft faced and unfaced. Fiberglass insulation can compress and lose r value and it s also unable to stop air from leaking out of or into your house. 7 staple sheets of 6 mil plastic over unfaced insulation to create a vapor barrier.

Use your straightedge to compress the insulation before cutting and use a very sharp utility knife to assure a good straight cut across the fiberglass batt. The friction of the fiberglass insulation material against the rafters baffles and plywood or wood slats is. Hot roofs are insulated above the rafters. Unfaced insulation has no tabs and stays in place with friction between the fiberglass and the rafters.

Unfaced batting insulation depends on a friction fit to keep it place. Attach insulation staple it to the rafters or scabbed on boards with a staple gun so that the paper backing is toward the interior of the room to act as a vapor barrier. Because the insulation is so close to the roof and you want to avoid unwanted moisture buildup these roofs will need to be completely sealed off.