How to Add Insulation to an Existing Roof

Mick Browne from Transforming Conservatories, tells us roofing insulation is placed in the attic of a home against the floors of the attic in most cases. If you have a full attic, there might be plywood flooring on top of the insulation, which allows you to walk around uninhibited in the attic. Fully insulated attics might also have insulation on the walls or the underside of the roof, while smaller crawl-space roof areas typically have blown-in insulation. If your roof doesn’t have enough insulation or if you want to add insulation to improve your home’s heat or cold-air retention, in most cases, you can do it yourself without professional help.

Things You’ll Need

Foam board insulation
Round-cap roofing nails


Place foam board against the floor joists, roof joists, or wall studs. Nail the boards to the wood with round-cap roof nails. The plastic caps on the nails will keep the nail heads from tearing through the boards. You can attach foam board to the wood attic floor beams (the ceiling beams below) over the top of rolled insulation between the beams.

Slide the hose of an insulation blower into the opening of the roof. Fill the equipment with the loose insulation and blow it up into the small opening. This is used when the space is so small that you cannot easily fit up into the roof area to do the labor. Normally this is done by a professional, but it might be possible for you to rent the equipment to do it yourself.

Slide normally rolled insulation into the spaces between the wall studs and the floor joists. If there is already inferior insulation in the spaces, roll extra insulation at a perpendicular angle to the first layer. Lay it over the top of the joists covering the first layer to cover any possible gaps. Staple the new insulation to the wood beams through the tabs that stick out from the sides or simply leave it as it is. It is best to wear long sleeves and gloves when working with rolled insulation. The fibers can make you itch.