How to Improve Insulation Levels of Flat Roofs

Flat roofs don't usually have a lot of attic space, and they sometimes barely give you a crawl space to work on things like ducts or insulation. If you have such a building and have determined that the insulation along the roof is lacking, you will have a difficult time installing additional batting if you haven't got the room to move. However, there are ways to increase the insulation no matter what your limitations are.

Things You'll Need

• Light
• Utility knife
• Batting
• Loose-insulation blower
• Lumber for fixture boxes
• Drill
• 3-inch screws

Instructions

Batting

1. Open the access to the attic area below the flat roof. Look to see if there is room for you to at least crawl in with rolls of batting. If there is, pull the batting rolls up into the space with you along with a light and a utility knife.

2. Roll the batting across the ceiling joists, laying the new batting in lines that are perpendicular to the current batting. Cut the batting as needed to fit the space. Also, leave areas free of batting where the previous insulation didn't cover, such as around light fixtures. These are fire hazards, and the insulation that is already installed should already be several inches away from these areas. You want to do the same with the additional insulation.

3. Roll out more batting to create more rows, keeping them right next to each other to fill in all gaps.

Blown Insulation

1. Rent a loose-insulation blower to blow insulation into the crawl space below the flat roof if it doesn't allow you enough room to work.

2. Build 12-inch-by-12-inch-by-12-inch boxes, with open bottoms but closed tops, using lumber or lumber scraps, and place them over fire hazards such as light fixtures. Drill screws at an angle through the sides of the boxes and into the joists to keep them from shifting.

3. Insert the insulation blowing tube into the attic opening and try to work your way back as far into the attic with the tube as you can. Have someone turn on the machine and keep the loose batting filled so that you can work. Spray the hose back and forth, aiming it toward the far corners of the attic.

4. Move back toward the opening as you spray the insulation. Once you get back to the opening, repeat the process on the other side of the opening until the only place that hasn't been sprayed with new insulation is right around the opening. Spray as much as you can, creating a tapered slope toward the opening.

References

• Easy 2 DIY: Insulating an Unfinished Attic
• Ask the Builder: Blown vs. Batt