If you have little holes or cracks in your attic or walls, canned spray foam insulation is the perfect product for filling them in and preventing heat transfer through them. But there are definitely some rules to keep in mind as you use this product. Adhere to these dos and don'ts for the best – and safest – results.
Do: Read the instructions before spraying the foam.
Each manufacturer's spray foam is a bit different. The label will tell you how far away from the surface to hold the can when spraying, how long to let the spray foam set, and how much foam to use in a given area. Don't assume that just because you've used canned spray foam insulation before, you can do the same thing this time; if you've bought a different brand, the guidelines may differ somewhat. And holding the can too close or failing to let the product set properly could lead to a botched job.
Do: Brush off the surface you'll be applying the foam to before application.
The cleaner the surface, the better the spray foam will adhere. Make sure you use a stiff brush to brush off surfaces like wood, metal, and masonite before applying the foam. If there is visible dirt on the surface, you may want to scrub it off with some water and then give the surface a day or two to dry before applying the foam. If you apply the foam to a dirty surface, it may peel away or not seal well.
Don't: Apply the canned foam to a large area.
Canned spray foam insulation is not the same as the spray foam insulation that professional builders use to insulate large areas like attic ceilings. It won't adhere well or do an effective job of insulating in these circumstances. It's only meant to fill in cracks, holes and crevices. The spray foam used to insulate large areas needs to be professionally applied because doing so requires industrial-grade equipment and large quantities of chemicals. If you need a large area insulated, get in touch with a professional spray foam applicator.
Don't: Throw the can away until it's empty.
If there is extra spray foam in the can when you're finished applying it, discharge it into a garbage bag or box before disposing of the can. Disposing of a filled spray foam could be dangerous if the can is accidentally punctured in the garbage truck or exposed to heat. Keep filled spray foam cans away from heat sources, like ovens and fireplaces, too.