How to Insulate a Vaulted Rafter

Adding insulation to your home increases its energy efficiency. If your existing ceiling doesn’t contain adequate insulation, or if you’re converting an attic into a living space, you can install batt insulation between vaulted rafters. Once the insulation is in place, you can attach drywall for a finished look if desired. While installing insulation between vaulted rafters isn't difficult, it may require working at unsafe heights. Use sturdy scaffolding and follow the safety measures recommended by the scaffolding manufacturer.

4-foot insulation batts (paper-faced)
Measuring tape
Utility knife
Staple gun

Instructions

- 1
  Install insulation batts that fit the width and depth of the rafter spaces. Rafters are generally larger than are standard wall studs, so measure the depth of the rafters before buying insulation batts.
- 2
  Insert the bottom of a 4-foot insulation batt into the bottom of a rafter space. The paper-facing side should face you. Since you’re insulating an angle, 4-foot batts are better than roll insulation.
- 3
  Push each batt in lightly. It should fit snugly between the rafters without being compressed. The insulation's R-value depends upon its loft.
- 4
  Unfold the paper attachment strips. Use the staple gun to attach them to the adjacent rafters, inserting one staple about every 12 inches.
- 5
  Insert additional batts, working from the bottom upward, until you come to the top of the rafter space. Measure and cut the uppermost batt with a sharp utility knife to fit within the remaining space. Cut insulation batts to fit around roof vents and soffit vents if necessary.

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