Spray Foam Insulation

For small and medium jobs, usually yes. Rim joists, basement walls, crawl spaces, sheds and air sealing in the attic are all well within reach of a homeowner with a gun-grade kit. You skip the minimum trip charge that most installers apply, and you can work one section at a time.

For new construction or an entire house, a professional crew with a two-component high-pressure rig will be faster, and the price gap narrows at that scale. If you do go DIY on a large area, a bulk pallet brings the cost per can down considerably.

Closed-cell foam is dense and rigid. It insulates at around R-6 per inch, blocks air and moisture, and adds some stiffness to the surface it's sprayed on. Open-cell foam is soft and spongy, insulates at roughly R-3.5 to R-3.8 per inch and absorbs sound well, but it lets moisture through.

The IxirPro and Magic Chems foams in this collection are closed-cell, rated R-5.66 per inch. That is the type you want for basements, rim joists, crawl spaces and anywhere that can get damp.

One inch of closed-cell foam is enough to air seal and gives about R-5.7. Two inches, about R-11, is what most people use on basement walls and rim joists. Attics and exterior walls in cold climates may need more. Energy codes set minimum R-values by climate zone, so check your local requirement before you start.

Don't try to reach full thickness in a single pass. Spray in layers of about an inch, let each one become tack-free (5 to 10 minutes), then add the next. Thick single passes cure unevenly and waste foam.

Yes, when it goes where the air leaks are. According to ENERGY STAR, homeowners save an average of 15% on heating and cooling costs by air sealing and adding insulation in attics, floors over crawl spaces and basement rim joists.

Spray foam is particularly effective because it seals and insulates in one step. Rim joists, sill plates and penetrations around pipes and wires are the spots where fiberglass leaves gaps, and they are the first places to treat.

The risk is during application. Uncured foam gives off vapors and sticks to skin, so wear gloves, goggles and long sleeves, work with good ventilation, and keep children and pets out of the area until the foam has fully cured, which takes about 24 hours. Our kits include a safety set for this reason. The Safety Data Sheet for each foam is linked on its product page.

Cured foam is rigid and stable. In living spaces, building codes usually require it to be covered with a thermal barrier such as 1/2-inch drywall, since exposed foam is combustible.

Yes, but temperature matters more than most people expect. The surface should be at least 40°F and the can itself should be at room temperature, ideally 60°F to 80°F. Cold foam comes out thin, expands poorly and doesn't stick well.

In a cold garage or crawl space, keep the cans indoors overnight. If you need to warm a can quickly, stand it in a bucket of warm tap water for a few minutes. Never use hot water or direct heat. These foams cure with moisture from the air, so in very dry conditions a light mist of water on the surface helps, as the Magic Chems and Y'allCanDIY labels recommend.