Stop Your Closet from Acting as a Wind Tunnel with Dow Spray Foam Sealant

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No baseboards - nice. The cobwebs are almost thick enough to fill the gaps themselves.

Okay, so some of you may be aware we have a sheetrock repair/faux beam bedroom remodel in the works, which is bad enough. Closet interiors were the last thing on my mind though, until we got further into this job. As I was sanding the sheetrock next to one of the rarely used crawl space closets, I noticed a hearty gust of cold air. Upon closer inspection, I determined it was coming from the closet door, which naturally I opened… into what I can only describe as a wind tunnel. It’s no wonder our monthly utility bill causes us to break out in hives.  

The air flow was strong enough that with some forgiving lighting and makeup thrown in, my flowing, blowing hair made me look as though I could have been on a professional photo shoot. I’d never paid much attention to it before; I knew the closet wasn’t finished, but didn’t realize it had no baseboards.

dow-sealantEven though it’s insulated, plenty of cold air is still coming through. Without the resources or time to finish off the closet interior, or to meticulously cut fiberglass insulation strips to be crammed into the cracks, our solution was Dow’s “Great Stuff” spray foam sealant.

During application

And yes, this stuff is great (and green according to NAHB Research Center!). The pressurized, expandable foam seeps and fills small gaps and cracks for an air- and watertight seal.  Once it hardens, you can easily cut away the excess with a utility knife. Unfinished areas can either be left alone, or covered with baseboard at any time in the future. The dried foam remains flexible, allowing it to expand/contract along with changing weather conditions.

Fully dried. At this point you can easily remove the excess with a utility knife.

Dow offers several types of spray sealant products, each with varying expansion levels and suitable for filling everything from small cracks to gaping holes. (We used soft and flexible for narrow cracks — technically its intended use is for windows/doors, but for the closet interior it worked very well.)

Some tips for usage:

  • Be ready to use the whole can. Once you start spraying, you’ve gotta finish, otherwise the foam will dry onto and plug the nozzle, and the rest is useless.
  • Don’t use the generic stuff because half of these products don’t work. I’ve found they often have inferior injection power. The air pressure dies and you’re done, left with half a can of foam you can’t use.
  • If you’re working in a finished area, keep an open garbage bag with you while you move from one spot to the next to catch any overflow or drips, (which will probably be more like huge globs).
  • If the foam does get away from you… LET IT SIT UNTIL IT’S COMPLETELY DRY! Do not try to wipe it up right away because it smears and leaves a huge mess. Once it does dry, it pulls/scrapes off easily and any clean up is minimal.
  • Wear gloves. We never bother and are sorry for it every time. This stuff is beyond sticky.

Dow “Great Stuff” foam sealant and other Dow spray sealant products are available at home improvement stores and at Amazon starting at around $5.00.

Photo of author

About Liz

Liz is a professional, custom picture framer based in Central New York. She and her contractor husband are currently renovating their second home together. At the time of this writing, they are not on speaking terms. Her love of making stuff with wood and DIY home projects began by watching her Dad. (It was also around this time Liz's incessant use of "colorful language" took root.) She's an avid gardener, stellar cook and doesn't throw like a girl: an all-around rad chick.

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4 thoughts on “Stop Your Closet from Acting as a Wind Tunnel with Dow Spray Foam Sealant”

  1. The stuff is also great for filling the voids in hollow plastic panels used in kids’ furniture and toy houses – also hollow-core dog houses. Makes them feel more substantial, (more) crush-resistant, insulates them. Just make sure you drill an air-escape hole at the opposite side, otherwise the stuff comes rushing back into your face from the injection hole at great pressure!

  2. I use the fireblock version often since I am rewiring parts of my house with 12-gauge romex. Many of the open holes through the top plates where the cable goes up from the wall switch to the attic are filled with a grimy dust from 50 years of air movement so I started filling them as I go. I also use the foam to seal around the ceiling fan boxes and ventilation fans which works well.

    I also ran into the problem of re-use since I usually only need the foam for one or two holes at a time. Since DIY’ers never follow directions I ignore the part about single-use and twist their advice of using acetone for cleanup and use it to save the can instead. Once I am done filling holes I take off the straw and drip some acetone through it before the foam hardens. Then I hold the can upright and spray until I get mostly air instead of foam and drip a little acetone down the nozzle. I can usually do this three or four times until it gets too gummed up to try again. Am I being too cheap? Maybe, but I hate to throw away a half-full can every time I use it. Thanks for the post.

    • Unscrew the straw and let it harden. Then use an 8″ or so long piece of the 12ga wire and run it through the straw. It pushes the plug right out. I fish the foam out of the can nozzle too. I use a piece of 12 ga ground to clean out the trigger portion of the nozzle. As good as new.


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