Stopping Air Leakage: Spot Sealing and Unvented Attics

If your utility bill seems absurdly high, your home’s heating/cooling system and lack of adequate amounts of insulation are two possible culprits. Cracks and openings in your house allow outside air in and let inside air out. While it’s good to have ventilation and to get fresh air, this is not the desired means to do so. Air leakage through cracks and openings is uncontrollable and can’t be monitored— you can never tell how much air is getting in or out. Attics are a specific concern in homes because of their inefficiency in regards to air leakage. How can you gain back control? There are different options for sealing you home and making your attic efficient. The first is called spot sealing. Using technology such as an infrared camera, your contractor can locate specific areas of leakage and directly seal those with spray foam. For all of the following techniques to be truly successful, you should have spot sealing done around your home.

Another option is to have the floor of your attic spray foamed and reinsulated. This process seals in all the air below the attic floor to prevent hot or cold air (in summer or winter) from infiltrating your living spaces.

You can also create an unvented attic by having the under-side of your roof sprayed with foam. By sealing your attic space at the roof, you essentially extend the conditioned (heating and cooling) space to your roof line. This makes it easier on ducts in the attic that normally have to move cold air through very hot temperatures during the summers. This option does have some complications—if for example your attic is as big as the usable living area of your house. Then, you have essentially doubled the amount of area in your home you have to condition. Also, any fuel burning appliances, such as water heaters, must be sealed (with an exhaust vent and air intake vent), as sealing the attic prevents outside air from coming in for combustion purposes.

It’s important to also understand that sealing your home doesn’t mean there is absolutely no air flowing through it. However, instead of having unpredictable air flow through cracks, you will have controlled ventilation, through your whole-house system of fans and ducts, as well as localized exhaust fans.