How to Install R-19 Insulation on Subflooring

Measure the length and the width of your attic's subfloor. Multiply the numbers you're left with by two. This will give you the square footage of your room.

Purchase enough R-19 insulation to cover your subfloor. Ensure your insulation rolls include a vapor barrier. Look for rolls that are perforated, so you don't have to do as much cutting.

Position your rolls of insulation as close to the entrance of your crawlspace as possible. Then, put on your protective mask, gloves and knee pads.

Slice open your rolls with a box cutter and wedge sections of insulation into the areas between your subfloor's joists. Cut the rolls to shape with a box cutter. Always ensure the vapor barrier is installed facing up against your floorboards. Secure the insulation in place with wire insulation fasteners. Push these between the gaps in your floorboards to hold your insulation in place. Space the fasteners at least 12 inches apart.