Air-Sealing Basics
Look high and low to find and plug air leaks that cost you money and comfort.

Synopsis: In this article, Mike Guertin and Rob Sherwood explain how air leaks from houses by way of the stack effect. They show locations in basements and attics where this commonly takes place and then demonstrate how to seal them using silicone, acoustical sealant, and spray foam.
While you might think that air leaks are a problem only with older houses, we’ve tested old homes that are pretty airtight and brand-new homes that leak lots of air. Air leaks occur wherever there is a joint, gap, or hole in the rigid building materials that enclose a house, such as wall sheathing, framing, and drywall.
Making an existing house more airtight is pretty straightforward: Find the holes and seal them up. Many air leaks can be found just by looking for spaces between framing and chimneys, electric boxes and drywall, and the mudsill and foundation. The fixes are often…
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