Spray foam insulation is an amazing product that performs better than nearly any insulating product on the market. Spray foam insulation products come in a variety of types, and spray foam rigs or a spray foam gun are fairly easy to source and rent. If you’re going to use spray insulation, though, there are three things you need to watch out for.
- Your spray insulation needs to be thick enough. This is especially an issue if you’re using closed cell spray foam kits, but it does happen with open cell spray insulation as well. Closed cell foam does not automatically fill the cavity it’s being sprayed into, so it’s crucial to spot check frequently and make certain some areas aren’t getting shorted. The coverage has to be uniform throughout the entire space. As much as 40% of a building’s energy loss is from poor air filtration, and spray insulation forms an airtight seal in every nook and cranny like no other type of insulation can. But key to getting that insulating power is making sure you’ve got the correct amount throughout the entire space.
- Your spray insulation needs to get all the edges. Another common problem people make when installing spray foam is failing to get the foam all the way to edges of every space. Sometimes an attic with a tray ceiling can have edges that aren’t immediately obvious. The spray insulation won’t be airtight and completely moisture proof as designed if it isn’t sprayed all the way to the edge. Before finishing up with drywall, try doing a blower door test. You can also use a fog machine to test for leaks.
- You need to understand the building envelope with unusually shaped buildings. Buildings that have an unusual envelope can be hard to seal correctly. While there might not always even be an air leak, there can be a place where thermal energy leaks out because a part of the envelope was missed in insulating. Every part of the building has to be insulting to a uniform thickness or there will be heat loss or heat gain in unacceptable ways. Also crucial is correctly identifying exactly where all the boundaries are between the unconditioned space and the main part of the building.
- Spray insulation can pull away from frames. This is fairly unusual, thankfully, but when it does happen it’s usually the result of bad mixing or application at too high a temperature. If you rent spray foam insulation equipment, make sure you know exactly how to use it. Don’t cut corners on mixing instructions or temp specs.
Spray insulation is an amazing product. The U.S. Department of Energy estimates that the average home in America uses about 56% of its energy in heating and cooling. Make your slice of that pie smaller by putting in the best insulating material that money can buy. Just be sure that you apply it to all the corners, in a uniform thickness, and understanding the shape of your building envelope.