17 Ways to Master Using Spray Foam at Home
Despite the obvious drawbacks-it’s messy, sticky and impossible to remove once it cures-there’s nothing better than spray foam for sealing energy-wasting air leaks (an so much more!). These are our best ways to use spray foam around your home.
Stop Drafts—and Mice!
Add an Extension Tube
Dampen for Fast Curing
For Pre-Cure Cleanup
Check the Expiration Date
Firm Up a Wobbly Showerhead
Squirt a little expanding foam around a loose shower arm, and it’ll be solid as a rock. Let the foam set up until it’s stiff and carve off any excess around the shower arm. Slide the cover plate tight to the wall and you’ll never know there’s foam holding things together. This same trick firms up any other loose or wobbly pipe.
Splurge on a Gun—You Won’t Regret It
If you’ve got more than a few windows or doors to seal with foam or are planning to make the whole house airtight, you should consider investing in a gun to dispense the foam. A basic model like the one shown here costs about $30. Guns have several advantages over cans with plastic straw applicators. First, turning the knob on the back adjusts the flow rate, so you can dial in the size of the foam bead to match the project. The long, rigid tip gives you better control and access, especially with the added disposable tip attached.
When you’re done using the foam for the day, just wipe off the tip and set the whole works aside. A ball in the tip seals in the foam so it won’t cure in the gun. You can leave it like this for up to a month without cleaning. When you do want to clean up the gun, buy a can of cleaner, screw it on, and spray until the gun is clean. You can also buy cans of urethane adhesive and use the gun to apply it.
Cut Cured Foam With a Bread Knife
A serrated knife with a flexible blade is perfect for cutting off excess foam. Just make sure the foam is completely cured and firm all the way through or it’ll stick to the blade.
Be Careful Where You Set the Can!
Seal Foam With Foam
Basement or crawl space rim joists are a major source of energy loss in a house, so it’s well worth the effort to add insulation and seal any cracks and gaps. A good DIY approach is to cut rigid foam insulation to fit between the joists. Cut it about 1/2 in. undersized so it’s easy to fit in. Shim the rigid foam in place with little chunks of foam. Then fill the space around it with expanding foam. Don’t forget to caulk or foam the joint between the sill plate and the foundation too.
Black Foam Hides in the Shadows
What’s special about ‘landscaping’ foam? It’s black, so it disappears in the shadows. And just like other canned foam, it expands to fill irregular spaces, sticks tenaciously to almost everything including stone, and cures to form a waterproof barrier, making it ideal for plugging holes in water features or retaining walls and even gluing wobbly stones in place. You’ll find this black expanding foam at garden centers, home centers and some hardware stores.
Big Holes Need a Double Dose
Protect Fragile Stuff
Got a fragile vase to ship? Encase it in foam to keep it in one piece. Start by lining the box with plastic wrap and filling it about a third of the way with foam. Let the foam stiffen enough to support the vase. Place a layer of plastic wrap on the foam. Wrap the vase in plastic wrap too. Set the vase on the foam and add a layer of plastic wrap on top. The two layers of plastic will allow the foam to separate into two pieces for easier unpacking. Now fill the rest of the box with foam. Remember, the foam will expand, so don’t fill it to the top. When the foam has cured, carve off any overflowing bits and seal the box for shipping.
Play It Safe Around Windows and Doors
Sealing around windows and doors is one of the most common uses for expanding foam. But it can actually push the jamb inward, making them impossible to open. Avoid this by using minimal expanding foam. It’s formulated to fill the space around windows and doors without excess expansion. Look for cans labeled for use on windows and doors. Another good idea is to fill the space with two layers. Push the applicator tip all the way to the back of the space and move it quickly along as you pull the trigger. Let this first layer expand and cure. Then add another if necessary.
Reuse the Straw
One of the biggest complaints about cans of expanding foam is that if you don’t use the whole can, cured foam clogs the applicator tip and you can’t use it again. There are several solutions to this problem, but the slickest we’ve found is to buy a can of carb and choke cleaner (at auto parts stores) and use it to clean uncured foam from the tube and trigger immediately after you’re done applying foam. The acetone in carb cleaner works perfectly on expanding foam. And the straw included with the carb cleaner is just right for inserting into the foam applicator straw. Be sure to wear safety glasses because the pressurized cleaner can blow back when you’re cleaning the straw.