Foam cans can be your best friend when sealing air leaks around your home. But, they can be your worst enemy as well as the foam can make a heck of a mess if your not careful.
Using spray foam requires a plan, especially if you are using single use cans. Make a list of all the places you want to seal and have all of them prepped and ready before you start the first one. What is prepped? Vacuum areas that have lots of dust, particularly drywall dust. Foam sticks to just about everything, but if it is stuck to a layer of dust that means it is not stuck to what it is supposed to be…and not air sealing.
Make sure you are using the right kind of foam, there are a few primary ones to pick from. The most common single use product is a gap filler that is usually yellow in color, this has some expansion and works well for most applications. Window and Door foam is usually more white than yellow, it has low expansion qualities so it doesn’t squeeze the window you just set. It’s also a good product to use around duct penetrations to keep from collapsing the duct. Big gap filler is just as the name says, a lot comes out and it expands a lot to fill large voids but can be tough to use in normal applications. Pest control versions of foam have additives that are unpleasant for pests, these are the same additives used in many building materials like wire sheathing. Then we have fire rated that is orange in color to make it obvious for inspectors.
Now that you have the areas prepped and you know what kind of foam to use, you need to figure out how to apply. Single use cans are fine for small projects, but anything more than a couple cans you are going to wish you had a foam gun. Professionals will use foam guns; no drips, controlled amount, higher yield, longer nozzle and the can will last a month without drying out. The downside with a gun; you have to keep it clean, it costs money and the cans are expensive.
With your work area clean and areas around protected (including you) use a spray bottle with water and lightly mist area. Apply spray foam, put less than you think you need, then lightly mist again. You’ll be impressed how much the product will expand and fill all those voids.
Use foam to seal between the indoors and outdoors, but only from the indoors. Even though foam will seal, it is not the right product for moisture sealing. A few cans applied in the right places can make an immediate impact to comfort and utility bills.
Common areas to seal are any drywall penetrations; outlets, switches, plumbing, fixtures, HVAC registers, etc… (around the electrical fixtures, not inside). Some less common areas are in the attic or basement at wire or plumbing penetrations or at the joint of drywall and the top plate.
Have questions on where the right places are to seal, or just want someone else to do the dirty work? Just ASK, at ASK Efficiency we provide the Energy Audits to determine where to air seal and offer the services to air seal as well.