How to Install Blown Flat Roof Insulation

What You'll Need
Blown insulation
Insulation blower
Spackling knife
Expanding foam sealer
Hole saw
Hole saw bit
Stud finder
Tape measure
Serrated knife

Installing flat roof insulation can be a bit challenging; however, with the proper tools any do-it-yourselfer can complete the job. Blowing insulation into a ceiling below a flat roof will require quite a few tools and materials. Fortunately, they can all be found at your local home improvement store. In fact, you may be able to rent an insulation blower from the home improvement store. Following the proper procedure can make this job quicker and easier than you had imagined.

If you don’t already have a drywall ceiling, install one before you begin the installation process. You will need more materials and may want to consider contacting a professional, as the job can be cumbersome. If you do decide to hang a drywall ceiling yourself, make sure that the ceiling has dried completely before installing your insulation.

Step 1 - Find the Studs

Before you begin, locate the studs in the ceiling and mark them on both sides. Locating the studs will help you determine where to cut the holes to access the inside of the ceiling.

Step 2 - Drill Holes

Now that you know where the cavities are located, cut a hole in the ceiling in each cavity, making sure each hole is large enough to fit the hose from the blower. The easiest way to cut the holes in the ceiling is to use a hole saw or hole-cutting drill bit.

Step 3 - Add the Blown Insulation

With the holes cut, you can begin to add the insulation to the ceiling. You need someone to help you with this. As you hold the hose and direct the insulation into the ceiling, your assistant will need to add the insulation to the blower.

It is important to gauge the amount of insulation you are using. You don't want to be halfway done and only have a little insulation left. If your progress is keeping pace with the amount of insulation, you are applying it evenly.

Step 4 - Seal the Holes

Once you have blown all the insulation into the ceiling, seal the holes with an expanding foam sealer. After the sealer has dried completely, use a serrated knife to cut any of the sealer that puffed up, and is protruding from the ceiling. Make sure to cut the sealer so the ceiling is level.

Step 5 - Finish the Ceiling

The last step is to finish the ceiling. Cover the hole in spackle and allow it to dry. Once it is dry, sand it, prime it with a primer sealer, and paint it to match the rest of the ceiling.

That’s it. Your flat roof is now insulated, so enjoy having lower energy costs and a more comfortable space.