I Can Do That! A new air-sealing product that’s not spray foam

As geeky as it may sound, I was really excited about this new product.  Having air-sealed my parent’s attic, and my attic, roughly 2 years ago, I was happy with the results but it wasn’t the easiest thing to do.   As a homeowner without access to a paint sprayer or professional spray foam setup, I did the next best thing: took a dozen cans of spray foam, just as many sets of gloves and a respirator into the attic and set to work using them while balancing myself on the ceiling joists and trying not to fall through the ceiling.  Ok, the balancing act must still be done, and still use the respirator if you’re working in a dusty area.  But the cool thing about this product is that it doesn’t offgas like sprayfoam and has a more precise application, unlike pulling the trigger on a can and waiting for the foam to shoot out and cover everything, not knowing where it will land or how much it will expand.  PROSOCO’s Targeted Interior Air Seal (TIAS) is exactly what it says–you can actually control where you put it.  And I love this too: it’s water-based, so you can wash it off your hands with soap and water (gloves are optional), unlike spray foam.  

The company’s video quickly shows how contractors use the product to air seal existing or new homes from the inside.  But I really appreciate this video from The Build Show Network, showing how a low-cost type of caulk gun or mortar gun can be used to apply the product in a way any DIY’er could do.  You’ll want to vacuum away any dust or debris first, then load your chosen gun applicator with the yellow, “whipped-cream consistency” product (which only comes in 2 or 5 gallon buckets).  But then you can go at your own pace to make sure you get around all the joists and sill plates in a controlled manner.  Some highlights of the product include the ability to apply it while people and pets are living in the home without worrying about off-gassing toxic chemicals:

• Low-odor, low VOC

• Bonds to most common building materials without priming

• Solvent-free,  Isocyanate-free and Phthalate-free

• Water-based formula for easy water cleanup

• Eliminates the need to remove exterior facades for air sealing applications

• It has a shelf life of 2 years in a tightly sealed container (you can unload the remains of the gun back into the bucket and reuse if it hasn’t dried)

This looks like a doable weekend project for anyone (or preferably a couple of people to help with prep and application) to air seal their basement or attic.  You’ll want to scope it out ahead of time to know the construction and where you’ll target application, otherwise you’ll waste time cleaning spots you didn’t need to seal (or getting the vacuum out mid-project when you missed a spot).   What we’re talking about is knowing the envelope of your home.  If you have an unconditioned attic, then the air sealing product will be around the penetrations in the top-floor ceiling (attic floor) like ceiling fan fixtures, light fixtures, around HVAC vents and bathroom fans.  The drywall in the top floor will provide the rest of the air barrier (if the rooms are paneled, though, it will be a more extensive job to try to caulk the edges of the panel together.)  Here’s an article for more tips on this particular job.  If you have an unconditioned basement, you’ll want to seal where the sill plate rests on the foundation on the inside, as well as where the rim joist meets the floor joists (check out the diagram below).  The reason for this is that the rim joist rests on the sill plate, and the bottom plate rests on the rim joist, and since we’re not able to get an unbroken line on these two surfaces because of the floor joists, it’s wise to caulk these little “squares” between the floor joists.   Plus, you’ll want to caulk any penetrations in the floor like under bathtubs (seal up large holes with foam board or wood first), around HVAC registers, and any electrical conduits or plumbing pipes.  Here’s an article showing all these sneaky air leaks under a home.  We would also encourage using this product over spray foam to seal your attached garage. 

Source: What is a Rim Joist?

What will you get for this project?  A more thermally-comfortable home, lower energy bills, and better air quality.  I can attest to these benefits, I just wish that this product had been around a few years ago!