Air leakage through holes, gaps and cracks can be the source of up to 30% to 50% energy loss. By using spray foam insulation to seal up holes where heat or cool air may be escaping, an investment as little at $15 could save as much as $500 in annual energy costs.
Where to Look for Air Leaks in Your Home
Look at Areas Where Different Materials Meet
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. Here are some key areas to examine:
- Door and window frames
- Electrical outlets
- Cable TV and phone lines
- Heat and air vents
- Where dryer vents pass through walls
- Bricks, siding, stucco and foundation
- Outdoor water faucets
- Pipe, wire and conduit penetrations
- Electric, gas and air conditioner penetrations
- Attic hatches
- Holes and voids in the garage
Applying Spray Foam Insulation
General Tips and Safety
- Carefully read instructions on the can label before use.
- Cover the floor with drop cloth or newspaper.
- Wear safety glasses, or goggles, and gloves when spraying the foam.
- Practice dispensing the foam onto a sheet of newspaper or into a garbage can.
- Foam insulation is flammable during dispensing. Remove sources of ignition, including pilot lights, until spray foam hardens completely (approximately eight hours).
- Mist the area with water before and after foaming to speed up curing.
- If you overfill an area, trim the excess with a serrated blade or utility knife once it has fully cured.
- Fill the opening less than 50% full when applying to allow for expansion of the foam. Overfilling causes wasted product and messy cleanup.
- If the foam in the straw applicator hardens, trim near the area where the foam has hardened and continue application.
Quick Instructions for Key Areas
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 is bearable.
- Remove 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.
There's often a gap in a basement where the pressure-treated wood-sill plate rests on top of the concrete foundation. In an unfinished basement, these gaps will be evident. In a finished basement with a dropped ceiling, the ceiling tiles 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 foam in a continuous bead, with no voids or breaks, to achieve an effective seal.
Plumbing pipe penetrations may allow bugs and unwanted air into the living space.
- Check for holes under sinks where the pipes enter from the floor or wall in all rooms that have running water (kitchen, bathroom, utility room and laundry room).
- Cover the area before foaming.
- Seal around the pipes at the wall or floor entrance.
Holes may be hiding under electrical outlet covers.
- Turn off the main electrical switch for the area of the home you'll be air-sealing.
- Use a screwdriver to remove all outlet cover plates.
- 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 it's flush with the wall.
- Replace outlet covers.
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 window / door and frame surfaces are clean.
- Fill the void between the window / door and the rough opening.
- Apply foam in a continuous bead, with no voids or breaks, to achieve an effective seal.
- For window applications, apply foam around all four sides. For door applications, apply foam around the top and sides only.