Containing home air leaks
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By JAMES and MORRIS CAREY
Friday, November 7, 2008 9:05 AM CST
Once again we are approaching winter. In many parts of the country flooding rains have occurred and in some areas snow already has fallen. This is the time of the year when we begin to think about what we can do to cut costs and get the best bang for our heating buck.
If you are like most Americans you already have insulated your attic and exterior walls. If you have not, it is time to do so.
If you are a real smart consumer you also have insulated your floors. But, there still is more. Insulation alone will not do the trick.
Another step, called infiltration control, should be undertaken.
Infiltration control refers to the containing of air leaks through penetrations in ceilings, walls and floors. It is critically important to a proper insulation job.
If you have a water faucet on an outside wall, chances are that it is connected to a pipe that supplies a plumbing fixture on the other side of the wall. Look outside the window in the kitchen, laundry or bath to see if this is the case.
If the pipe protrudes from a wall cavity rather than from the rim of the floor, that pipe is in a prime location to cause an air leak.
Holes on the inside of your home normally will be found in the wall beneath and behind plumbing fixtures (toilet, sink shower, etc.).
The biggest air leaks usually can be found under cabinets. The holes in those locations often are enormous.
Another location where infiltration can occur is in the attic where pipes in walls travel up through the ceiling. When this condition exists, air travels from the attic down into the wall cavity and out through the first hole it finds — usually a wall switch or a plug or a heat register.
Plumbers and electricians are notorious for giving themselves plenty of room to work during the construction process. It is not uncommon to see a two-inch hole surrounding a one-inch pipe. Or worse yet, a one-inch hole surrounding a three-eighths-inch wire.
Actually, these are more than points of infiltration. They are small wind tunnels.
More easily identifiable points of infiltration are gaps in exterior siding and window and door frames.
Years ago we often stuffed insulation into the gaps that air flowed through. That was because caulking wouldn't hold up in such large voids. We also used tin plates at the bottoms and back of cabinets where pipe penetrations were surrounded by large, gaping holes.
We would cut a hole in the center of the plate that closely fit the size of the pipe. The overall size of the plate had to be large enough to cover the gap, with enough left over for fastening with screws or nails.
Large or small expanding foam is now our first choice for all gaps of all kinds. It’s inexpensive and quick — and very easy to use.
Here’s a tip: Never attempt to clean expanding foam from a surface until after it dries completely. When wet expanding foam simply cannot be easily removed from a surface. Once dry it can be quickly wisked away.
James Carey and Morris Carey, known as the Carey Bros., are nationally-recognized experts on home building and renovation.
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