Adding Insulation to your Attic

If your attic has no insulation, you will need R-30 kraft-faced insulation, or maximize your energy efficiency with R-38. If you’re adding to existing insulation, you should always use unfaced products.

Kraft- or Foil-Faced Insulation with Vapor Retarder

This type of insulation has either a foil-backed facing or kraft paper layer attached. The attached facing layer helps control the amount of moisture vapor that passes through the insulation that could collect inside ceilings, exterior walls and floors. Kraft and foil facings are combustible and have to be covered with an approved interior finish (i.e., drywall).

Unfaced Insulation

Unfaced insulation has no foil- or kraft paper-faced vapor retarder.

Rolls

Rolls are long strips of insulation rolled into bales. You measure the length you need and cut it off with a utility knife. Rolls are best for covering large open areas, like attics and floors.

Batts

Batts are pre-cut lengths of fiberglass insulation. Batts are available unfaced, or with aluminum foil or kraft paper facing.

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Installation Tips

• Use boards or sheets of plywood to provide a safe place to sit or kneel in an unfinished attic as well as a surface on which to cut the insulation.
• Begin by installing the insulation at the outer edge of the attic space, then work toward the center.
• If your joist cavities are not completely filled, fill them to the top with the appropriate thickness of insulation, and then add an additional layer of insulation in the perpendicular direction.
• If your joist cavities are filled, simply lay your new insulation in long runs perpendicular to the direction of the joists. You can use any leftover pieces for small spaces.
• Be sure to extend the insulation far enough to cover the tops of the exterior walls, but do not block the flow of air from the eave vents.
• Remember to keep your insulation at least 3 inches away from any recessed lighting fixtures. Only fixtures rated “I.C.” (Insulated Ceiling) are designed for direct contact with the insulation. Insulation placed over an unrated fixture can cause the fixture to overheat and perhaps start a fire.
• Additionally, insulation should always be kept at least 3 inches away from metal chimneys, gas water heater flues or other heat-producing devices.
• When you’re working around masonry chimneys or other areas with small openings, stuff these spaces with small pieces of unfaced insulation which will not burn.

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