The type of spray foam insulation you and your contractor choose for your project will depend on the location where foam will be sprayed and to a lesser extent, your budget. As you may know, spray foam insulation falls into two general categories, open cell and closed cell. Each has its advantages over the other in specific applications. Knowing how each will perform in the exact spot where you need insulation will determine the type of foam your contractor recommends.
Another thing to keep in mind is that spray foam insulation is really not a home improvement project that you should ever consider doing yourself. There are elements to the process that require specific training by a manufacturer in the proper and most effective installation of their products. Without this training, and safety measures that are also learned and acquired along the way, you might end up doing the job incorrectly and having to start over multiple times, which wastes material and time. Further, if you don’t get the adhesion part just right, you have also wasted a great deal of money if the foam does not marry itself to the substrate initially.
Spray polyurethane foam insulation is made by blending two ingredients. One ingredient determines if the foam is open cell or closed cell, and the other part of the blend contains polyols and a catalyst which causes the blended material to foam once they are joined in the nozzle of the spray gun. When the blend hits a wall, or between joists in a roof, it quickly expands to 100x its size.
The type of foam that is best for your project is based on what you are trying to accomplish. While both versions of spray foam insulate, only one, open cell foam, is the best sound insulator. Open cell is also less expensive than closed cell foam. If you are going to be insulating a location where moisture is an issue, then you will want closed cell foam because it is a moisture and water vapor barrier in addition to an insulator. If your goal is to strengthen up wall construction as you insulate, such as in a hurricane-prone area, then you will want closed cell foam because it is an effective structure strengthener because it dries harder and denser than open cell insulation.
Whichever type of foam you choose, know that you have chosen the best insulating product on the market. It does the best job of insulating per inch than any other option available.