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How to Install Roll Insulation

Roll insulation can be used anywhere in your home, although they are best for covering long unobstructed areas like attics and crawl spaces.

Roll insulation can be cut to fit any size cavity and are typically available in faced and unfaced. JM also offers ComfortTherm®, which is poly-encapsulated, or wrapped in plastic, for a more comfortable installation with less itch and dust. The plastic facing also serves as a vapor retarder.

Faced insulation is used in exterior walls as well as attics, finished basements, ceilings, floors, knee walls and cathedral ceilings. Like other forms of insulation, rolls are available in a variety of R-values.

When choosing roll insulation, make sure you use the most appropriate R-value. Our R-value Estimator in the Site Toolbox can guide you.

Roll Insulation Tips

  1. Open the packages by cutting lengthwise through the side panel. Be careful to avoid cutting the product or facing. The insulation will quickly expand to its full volume when the bag is opened.
  2. Rolls must be measured and cut to fit into wall cavities. Cut insulation about an inch wider than the space using a sharp utility knife against a safe backstop, such as an unfinished floor or other smooth, flat surface. Always cut on the unfaced side of the batt.
  3. Cut the insulation to fit properly. Don't double it over or compress it. Compression changes the R-value of the insulation.
  4. Gently push insulation into the cavity so that it sits all the way, especially at the corner and edges. Then, fluff it to its full expansion by pulling it forward to fill the depth of the cavity. The fit should be snug.
  5. With faced insulation make sure the vapor retarder is facing the conditioned interior space, unless building codes specify otherwise.
  6. Allow friction to hold the insulation in place. Or you can staple the flanges of faced insulation to the insides or face of the joists. (Stapling on the inside is preferred by many drywallers because it leaves the edges of the framing members easier to locate. However, your local building codes may require you to overlap the flanges and staple them to the edges of the framing members.)
  7. Take care not to stretch the facing too tight as you staple, which can over compress the insulation, and avoid gaps and puckers.
  8. Secure floor insulation with wire fasteners, sometimes called "lightning rods." Press the fasteners so they bow up gently against the subflooring without compressing it. Space the fasteners at least six inches from each end of the batt and 12" - 24" apart.
  9. When installing rolls in an unfinished attic or other large open area, simply unroll the insulation in place.
  10. Wherever there are adjacent rolls, make sure they fit snugly together.

Related Products

ComfortTherm® Batts and Rolls


ComfortTherm® insulation is a lightweight, thermal and acoustical insulation made of long, resilient glass fibers bonded with an acrylic thermosetting Formaldehyde-free™ binder.

Kraft-Faced Batts and Rolls


JM's Kraft-Faced Batts & Rolls are made of naturally white, Formaldehyde-free™ fiber glass, reducing environmental concerns including the risks of poor indoor air quality and the effects of manufacturing on the environment.

Unfaced Batts and Rolls


JM's Unfaced Insulation is a lightweight thermal and acoustical fiber glass insulation made of long, resilient glass fibers bonded with an acrylic thermosetting resin made without formaldehyde.

Roll Insulation
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