How to Apply DIY Spray Foam Insulation

Start by looking at areas where different materials meet. This will be where most insulation is found and where additional waterproof foam spray would be beneficial. For very large areas, you can always learn how to install insulation that's sold by the roll, not by the can.

Check between brick and wood siding, between foundation and walls, and between the chimney and siding. Also look in the basement and crawlspace, attic and the interior and exterior of your home for gaps and cracks where air may be escaping.

Examine these key areas closely:

• Door and window frames
• Baseboards
• Electrical outlets
• Cable TV and phone line holes
• Heat, dryer and air vents
• Bricks, siding, stucco and foundation
• Pipe, wire and conduit penetrations
• Electric, gas and air conditioner holes
• Where pipes pass through walls, including outdoor faucets
• Attic hatch door
• Holes and gaps in the garage
  

• Carefully read the instructions on the foam sealant label before use.
• Cover the surrounding area with a drop cloth or newspaper and protect yourself with safety goggles and work gloves.
• These sprays are typically flammable, so keep the sealant away from flames.
• Practice dispensing the foam onto a sheet of newspaper or into a garbage can until you have control over the flow.
• Mist the drafty area with water before and after foaming to speed up curing.
• If you overfill an area, trim off the excess foam with a serrated utility knife once it's cured.
• Fill openings slightly less than halfway full, allowing the sealant to expand.
• If the foam in the straw applicator hardens, trim the straw down until you can spray foam again.

Attic Hatch Door

To help keep air from escaping through the attic, seal the gap between the attic hatch door frame and the ceiling joists.

• Pick a day when the attic temperature isn't extremely high or low.
• Remove the loose pieces of insulation in the gap before foaming.
• Fill in the space between the four sides of the attic hatch door frame and the ceiling joists.

Sill Plate

There's often a gap in basements where the wood sill-plate rests on top of the concrete foundation. In a finished basement with a dropped ceiling, the ceiling tile will need to be removed to access the sill plate and the foundation.

• Cover the basement floor before foaming.
• Slowly fill the void, moving the can along the gap as you foam. Apply a waterproof foam spray in one continuous bead, with no voids or breaks, for an effective seal.

Plumbing

Where a plumbing pipe goes through a wall, small gaps may allow bugs and unwanted air into your home.

• Check for holes under sinks where the pipes enter from the floor and walls in rooms that have running water (kitchen, bathroom and laundry room).
• Cover the area before foaming.
• Seal around the pipes at the wall or floor entrance.

Electrical Outlets

Holes may be hiding under electrical outlet covers.

• Turn off the main electrical switch for the area of the home you'll be foam-sealing.
• Check for gaps between the wall and the metal or plastic box that houses the electrical socket.
• Fill the gap around the perimeter of the electrical box. Avoid foaming anywhere inside the box.
• Allow foam to cure completely. Trim excess foam so the foam is flush with the wall.

Window and Door Framing

Installing new windows and doors can significantly improve a home’s energy efficiency. During installation, make sure to fill the gaps around the window or door frame and the rough opening.

• Ensure that the frame surfaces are clean.
• Apply foam sealant spray in a continuous bead, with no voids or breaks, to achieve an effective seal.
• For window applications, apply waterproof foam around all four sides. For doors, apply foam around the top and sides only.