You’re Here: Home » Home Insulation  »  How To Install  »  By Product Style  »  Blankets

How to Install Blanket Insulation

Blanket insulation comes in rolls up to 70 feet in length. Some specialty products may come in rolls up to 100 feet long.

Blankets are particularly useful in long runs between ceiling or floor joists and for areas requiring insulation longer than 96 inches. Blankets are primarily used for insulating unfinished walls in basements and crawl spaces.

Blanket Installation Tips

Unframed, exterior basement walls should be insulated with blanket insulation, which can be installed horizontally or vertically. Typically, the blanket is held against the sill plate at the top of the basement wall with furring strips. In addition to the furring strips, you will need patch tape, and depending on the installation method you choose, possibly a Hilti-type gun and special fasteners for driving into concrete or cinder blocks.

Horizontal Installation

  1. Seal around all penetrations in band joists. Any walls that leak water must be repaired before insulating.
  2. Pre-drill an ample supply of 1x2 furring strips.
  3. Measure the length of insulation you'll need for the full wall and cut it on the unfaced side.
  4. Grip the insulation by the flange, and with the faced side toward you, position it against the sill plate at the top of the basement wall. Then position a furring strip and nail through the furring and the flange to the sill plate to secure the insulation. Whenever possible pull the insulation behind any ductwork, plumbing, or electrical that may lie along the walls. Otherwise, carefully cut and fit the blanket around obstructions.
  5. When you cover the full wall, you'll need to attach a second length of the blanket to the lower edge of the first one. If you have cut a piece to fit and there is no flange, create one by pulling back the insulation. Overlap the flanges of the top and bottom pieces so that the insulation butts together tightly. Then, staple through the flange to hold the pieces together. An alternate method is to attach furring strips to the wall at the mid-point and bottom of the wall then staple the blanket flange to the furring strips.
  6. To give the insulation a finished look, tape over all joints, seams and stapled edges with 3"-wide, white vinyl patch tape.
  7. Cut small pieces of batt insulation to fit against the header joists and push them into place between each floor joist.

Vertical Installation

  1. Seal around all penetrations in band joists. Any walls that leak water must be repaired before insulating.
  2. Cut lengths of insulation a few inches longer than the height of the walls.
  3. Attach the blanket to the wall using furring strips or a Hilti-type gun to drive fasteners into the concrete or cinder blocks. Fit adjacent blankets tightly together.
  4. Trim the bottom of the insulation flush with the floor.
  5. To give the insulation a finished look, tape over all joints and with 3"-wide, white vinyl patch tape.
Copyright ©2014, Johns Manville, Inc. All Rights Reserved. Global Sites | SpecJM.com | Site Map | News Archives
Industry Resources | Privacy Policy | Legal Notices
Product & Sales Information: (800) 654-3103