Part One - Purchasing DIY Spray Foam Insulation

1. You will need a respirator with cartridges and filters rated for the kit foam you are going to use (ask the manufacturer), safety glasses, coveralls, and disposable gloves.

2. To figure out how much DIY Spray Foam Insulation (kit foam) you will need multiply the square feet you need to cover by the thickness in inches you plan to apply. The result is a unit called a board foot; many kits are sold by the board foot. Example: 400 s.f. x 3 inches thick = 1200 board feet. Add about 10% to your estimated need and even more if you will be applying in winter temperatures. The largest kits are about 600 b.f. and the smallest are about 12 b.f. Slow rise kits, used for filling blind cavities rather than spraying, are sold by the cubic foot rather than the board foot. You can purchase kit foam online from many websites and at contractor stores but it is rare at hardware or retail box stores. Tiger foam, Fomo foam and touch n' seal are common brand names but if you type "kit foam "into a search engine you will get plenty of hits. Most of the raw materials come from the same manufacturers (Dow or BASF), they are just rebranded so all brands are about the same quality.

3. Kit foam, unlike single part foam (a.k.a. can foam or gun foam) does not have a long shelf life. Get as much as you need and plan to use it up in 1 to 2 weeks. It may last longer than that but not likely. The chemical may be good but the valves freeze up and then it can produce really bad foam.

4. You can buy kit foam in various sizes and in various formulations. Spray, fast-rise, or spritz foam is the most common. It is closed-cell, high density, spray applied foam and adheres to many surfaces very well. Slow-rise, pour, or injection foam is closed-cell, high density foam that does not cure as fast so it is better for filling large or blind cavities than for spraying. Slow-rise foam IS NOT FOR BEGINNERS, without a proper understanding of it you can blow walls and push masonry. Open-cell, low density kit foam is also available but not very easy to find. A related product, cartridge foam, supplies the 2 chemicals in cartridges (picture a big epoxy container) and comes in many formulations. This is a good product but not really geared for the DIY market, experienced knowledge of foam is required.

5. Kit foam parts: Two canisters- one containing chemical A and the other chemical B, a hose with a gun attached, replaceable gun tips called mixers. The canisters look like lightweight propane tanks and have a valve in top. NEVER open the valves unless the gun hose is properly screwed on. The gun and hose has a screw-on union that attaches to the canister valves, make sure it does not get cross threaded. Hoses can be ordered in several lengths, and this matters because a full 600 b.f. kit can weigh nearly 100 lbs. Depending on how and where you will be using the kit you may want more or less hose. I've been in a cramped attic with a large kit and short hose, not fun. Finally, the mixer; these are little buggers but boy are they important. The mixer mixes the A and B chemicals together as they are being pushed through the gun. If you plan to foam a large area all at once you may only need 10-20 mixers, if you plan to do a lot of stop and go foaming, like sealing individual air leaks, you may need 40 to 50 mixers. For detailed air sealing you may also want to consider one part can foam.

6. Kit foam is expensive on a per unit basis but can be much cheaper than hiring a professional if you have a relatively small area to do. Plan on paying at least $100 (including shipping) for the smallest kits and $700-900 for the largest.


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Next --> Part Two - Understanding DIY Foam Insulation