Cellar to Attic   Cellar to Attic

Air Sealing

Air leakage in your home represents a sizeable chunk (typically about 25 to 40 percent) of your annual heating/cooling bill. Those leaks also make homes uncomfortable and unhealthy. Air leaks can contribute to problems with moisture control and cause moldy and dusty air to enter your living space through cracks and openings between the living space and attics or foundations.

Cold air leaking into your home during the heating season can make the basement and main floor uncomfortable and difficult to heat, even with the thermostat turned up. In fact, as you continue to raise the thermostat, even more cold air is drawn in, usually at lower levels, as the house itself becomes even colder (stack effect). All this time your warm air is escaping out of your house through cracks and openings. This warm air leaking out of your home carries moisture in vapor form which can condense on cold surfaces in your attic, crawl space, or inside wall cavities causing long-term deterioration. These problems may include rotting roof sheathing, rotting framing members, wet insulation, mold growth, buckled siding, musty odors, ice dams and stained ceilings. These air leaks do not stop in the summer. The process is simply reversed with hot attic air being drawn down into your home and cool, air conditioned air escaping through the cracks and openings of your home.

It makes more sense to have air sealing done properly and reap the many benefits such as:
• lower energy bills
• improved comfort
• better control of indoor relative humidity
• improved indoor air quality
• fewer condensation problems
• reduced/ eliminated ice dams
• a more quiet home
• less impact on our environment

Where are the typical air leaks?
There are usually many air-leakage paths between your living space and your attic such as those coming from electrical wires, electrical boxes, plumbing vents, chimneys, recessed light fixtures, exhaust fan housings, interior wall top plates, dropped soffits, open wall cavities, attic hatches and many others.

Another important area to seal is the top of foundations (basement sill plates). We use two-part foam to seal and insulate these areas.

Can my home be sealed up too tight?
Seal tight and ventilate right. Your house may have a significant reduction of ventilation as a result of air sealing. It is important to monitor the relative humidity in your home. For that, consider purchasing a good quality hygrometer. While there is no "magic" relative humidity to maintain, it is recommended a home's relative humidity be kept between 30-50% during the heating season. During extreme cold weather, an even lower relative humidity may be necessary to prevent condensation from occurring on surfaces such as windows and exterior walls.

Seal tight and ventilate right. What does that mean?
It is better to rely on controlled ventilation rather that your home's air leaks for ventilation. Relying on air leaks for ventilation means the air that you and your family breathe is coming from the air in your basement and attic. This potentially unhealthy air is continuously being drawn into your living space because the air leaks are not sealed. Therefore, it is recommended that you air seal your home and then control your home's relative humidity with properly installed mechanical ventilation such as bath/kitchen fans vented to the exterior or general ventilation fans which can run continuously.

What are some common sources of moisture in homes?
humidifiers, cooking, bathing, respiration/perspiration (humans & animals), indoor clotheslines, houseplants and firewood stored indoors.



Air Leaks picture
Needs sealing
Needs Sealing 2

Here are some common problem areas that we see in attics. You can tell there is air movement by the dirty insulation. These areas need to be air sealed.





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