Air Sealing Part 1 - The Basement

Good day everyone.

Air sealing has become the number one priority in Weatherization. Air exfiltration / infiltration effects heat / cold loss - and therefore your wallet. Finding leaks using the blower door first - then the trained eye - helps you seal off the home from the exterior. The exterior INCLUDES the attic.

You've seen people put plastic on the windows and shoot caulk in various spots. This is primitive air sealing - however it is a start.

Let's start in the basement. The number one exfiltration spot is in the band joist. Water lines, cable lines, electrical lines, etc. - are routinely NOT sealed off from the exterior, allowing heat and cold to escape. Foam in a can (purchased for under $10 a can from Home Depot and Lowe's) seals up these holes very easily. Please beware - if you get the foam on your clothes, it is extremely difficult to get out. I've been yelled at many a time by Mrs. Energy Guy for ruining clothing. It's kind of like The Energy Guy's kryptonite. Also, if you happen to get some on the floor, washing machine, etc. - do NOT attempt to wipe up immediately. Let it harden and scrape it up later. One last tip - if you start a can of foam, use it. It does not store once it has been started.

The next most common exfiltration / infiltration spot is the band joist / sill plate connection - especially in older homes. The area between the block and the wood can have gaps completely around the perimeter of the home. For these areas, simply silicon caulk around the edge where the block meets the wood.

Window frames (not the glass block windows) are sometimes extremely leaky. Once again, a bead of caulk can do the job.

How can you visually spot air leakage? Look for cobwebs. Cobwebs are a sign of a fresh air source - spiders spin these cobwebs near fresh air sources to attract bugs for lunch / dinner.

Crawl spaces have their own set of air issues - and we'll address them separately in a future Energy blog.

Please note: Mom and Pop hardware stores sell foam as well. I'm not endorsing either Home Depot or Lowe's - however they're recognizable and yes, I shop there as well. Without the cape...

Next Topic - Air Sealing Part 2 - The Attic