Fiberglass Insulation Roof Rafters

Vented attics have insulation installed underneath the roof deck in direct contact with the decking.

Fiberglass insulation roof rafters.

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. 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. Air sealing hot roofs is critical. And owens corning ecotouch high density insulation products are designed specifically for these rafters.

The rafters in cathedral ceilings are usually made of 2x10 ft. The friction of the fiberglass insulation material against the rafters baffles and plywood or wood slats is. R 30c and r 38c are available in both kraft faced and unfaced. Unfaced insulation has no tabs and stays in place with friction between the fiberglass and the rafters.

7 staple sheets of 6 mil plastic over unfaced insulation to create a vapor barrier. Unfaced batting insulation depends on a friction fit to keep it place. 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.