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Exterior Walls

Exterior walls should be insulated to maximum R-value, which is determined by the thickness of the stud wall. If walls are constructed of 2" × 6" material, then Roxul ComfortBatt™ R22 (5½”) batts should be used. Do not attempt to squeeze R22 batts into a 2" × 4" stud wall.

1. Install ComfortBatt™ between wall studs.

  • Eliminate gaps and make sure the ends butt snugly together.
  • Ensure the surface of each batt is flush with the interior surface of the studs.

2. Use a long serrated bread knife to cut pieces to fit around windows, doors, electrical boxes, and anywhere requiring less than a full size batt. Do not compress the insulation as this reduces effectiveness.

3. To insulate behind an electrical box, cut a notch out of the batt that allows it to go behind the box. Butt fit firmly against the 3 exposed sides.

4. A vapor barrier must be integral with boxes. Ensure that the electrical “box” barrier overlaps and seals to the main vapor barrier.

5. To insulate around wires, score insulation face with a long serrated knife.

6. Then snap ComfortBatt™ over the wire between the studs.

7. Roxul insulation can be cut to insulate around objects such as pipes, ductwork and electrical boxes.

8. Check local building codes for approved vapour barrier/retarder information.