How to Insulate Attic Flooring

A worker blowing white cellulose insulation into an attic
  • 2-4 hours
  • Beginner
  • 100-175
What You'll Need
Loose or roll insulation
Insulation blower
Protective clothing
Face mask
Caulking (optional)
Tape measure
Plastic sheeting

Installing insulation in your attic can save you money on energy bills by reducing the amount of heat lost through your roof. While you could hire a professional to complete the project, you can save even more money by doing it yourself. Check out these simple steps to begin.

Measure the Dimensions

To make sure you purchase the right amount of insulation material for the job, you should carefully measure the attic's flooring area. Decide whether you’d like to use loose or rolled insulation, as they both have their own pros and cons.

Examining the Floor

While measuring, you can also examine the attic floor to see if there are any gaps or cracks that could make installing insulation less effective. Fix any of these gaps or cracks with caulking before continuing.

Prepare the Attic

After gathering all the necessary tools and materials, you must correctly prepare the space. Move any portable items away from the area, and clean the attic of any dust and debris. If the light in the attic is insufficient, you should put some temporary lighting in place before you begin.

Install the Insulation

Warning: Many types of insulation contain materials that can irritate your skin and respiratory system. Protect yourself with clothing that covers all of your body, gloves, and a face mask before continuing.

Installing Rolls of Insulation

For rolls of insulation, begin at the outer wall and lay the moisture barrier down against the floor surface. Tuck in the edges of the material against the joists, and unfurl it along with the space between them. Without stretching it, carefully pass the insulation beneath any power cables. If the roll is longer than your workspace, use a pair of scissors to cut it before tucking all the edges against the joists.

Continue in this manner throughout the attic, and don’t forget to do the same with the top of the access hatch. Ensure that you leave a gap of at least 3 inches between the insulation and any lighting fixtures to eliminate fire risks.

Installing Loose Insulation

If the joists in your attic are of a sufficient height, and there isn’t a fan installed, you can use loose insulation. Pour the loose material over the attic floor, so that it’s as evenly distributed as possible. Use a gloved hand to spread the material beneath cables and pipes. You could also use an insulation blower to evenly distribute the cellulose insulation. However, you can’t use this type of insulation for the top of the access hatch, so attach a piece of blanket insulation there, instead.

Clean Up

Make sure that any insulation stays in your attic, and that it doesn’t transfer to the rest of your home. Bag up any excess insulation before taking it out of the attic, and change your clothes. Do not wash the clothes you used to install the insulation in with your normal laundry.