Installing Foam Insulation Board in an Attic

A close-up on the corner of a piece of cellulose insulation.
  • 24-96 hours
  • Intermediate
  • 350-600
What You'll Need
Foam insulation boards
Construction adhesive
Drywall or flame resistant panels
Handsaw: preferably a type with a fine-tooth structure to minimize the level of foam dust created
Craft knife
Vapor barrier sheets
Protective gloves
Protective goggles
Protective face mask
Furring strips
Tape measure

Installing foam insulation boards in the attic is no that hard and can save you money compared with professional installation. Foam board insulation in the attic can cut down on energy costs and simultaneously promote a more environmentally-sound way of daily living.

Foam insulation boards are the best material with which to work when undertaking a do-it-yourself project because foam insulation boards are easy to maneuver, are generally lightweight, and can be placed in almost any part of the house, thus making them ideal for the attic, which can be difficult to navigate. Here is a step-by-step explanation of how to install rigid foam insulation.

Step 1—Remove Insulation

Remove any existing pieces of insulation that might have been covering the attic walls until now. Remove the old insulation boards carefully, without causing any damage to the walls.

Step 2—Install Insulation Boards

Foam insulation boards can be attached to concrete walls as well and in such a case care should be taken not to chip the cement. When installing foam insulation boards in the attic, make sure you start from one corner and work your way around the room.

Step 3—Place Caulking and Furring Strips

Place a strip of caulking at every junction where the foam boards will have to meet the support structures of the attic. Place the furring strips on the wall carefully, making sure they are aligned in a straight plane with one another.

Step 4—Cut Foam Boards

The next step involves cutting out the foam boards according to precise measurements. Remember that the foam boards have to fit between the furring strips and should be snugly placed, so it is important to measure the dimensions carefully before cutting them. Foam insulation boards usually come in 4x8 foot panels.

Step 5—Caulk

Once the board is cut, affix a bead lining of caulk down one side of it. This prepares the board and makes it ready to fit into the furring strip. Slide the caulked side of the board into the furring strip and make sure that it fits tightly into the strip, with no gaps. Take the next board and caulk it down one side the same way. Slide the caulked side of the second board into the side of the first board that has not been caulked.

Step 6—Insulate from Moisture

Once you have covered the entire area to be insulated, use plastic sheeting or a vapor barrier sheet to cover the foam boards. This prevents any moisture-related problems.