Spray foam is an insulation material. It is sprayed into cracks and crevices, where it expands to form an airtight and moisture-resistant seal. This seal can save you money that otherwise might be spent on heating or cooling. It also protects buildings from both pests and mold. It is much more expensive than traditional insulation, such as fiberglass, and it can create a mess if it seeps out of cracks and holes before it dries.
Spray foam is a chemical substitute for traditional home insulation methods like fiberglass. The chemical agent is stored in canisters and sprayed into walls, holes and cracks with a special application device; it then expands and dries, forming a barrier. This barrier can hold in air and heat, keeping houses warm and lowering heating bills, or it can be used to plugs leaks or supplement existing insulation.
There are several different types of spray foam insulation, many boasting environmentally safe and non-toxic substances. Foam sprays are similar method in that a polymer and a foam agent are combined into a liquid and sprayed through a nozzle. When it encounters oxygen, the liquid expands into foam, reaching as much as 100 times its original size before it dries as a mass of polymer bubbles. The foam can be either open-cell, which is lighter but not as insulating, or closed-cell, which is denser and more protective. If the foam is being applied as a house-wide insulation, it is usually sprayed as the wall is being built and allowed to dry before the drywall is put up.
Traditional fiberglass insulation is set up in layers, and although it can cover a wide area, it leaves gaps and cracks where air can escape, lowering the temperature of a building. Spray foam insulation expands naturally to fill gaps and leaves no cracks, keeping the air inside more efficiently, keeping the building warmer and lowering the heating or cooling bills. The foam also prevents the build-up of moisture, lowering the incidence of mildew and mold problems, and makes it more difficult for insects and other pests to burrow into a building. In addition to being durable, spray foam is also very adhesive, and clings tightly to surfaces.
Because spray foam expands so much and is so adhesive, it usually requires additional clean-up work after the foam is applied. It must be scraped away from outlets or necessary gaps. If the foam is being sprayed in an already-constructed building, it will often need to be cleaned from small cracks it has expanded into. If too much foam is sprayed, then the integrity of the wall can be compromised. Spraying foam is thus a technical process, and you will need to hire someone to spray it for you on a large scale, adding to the expensive. Proponents of spray foam claim that the high application cost is offset by the money saved through good insulation after several years of use.
Spray foam is used in existing houses in small quantities to seal cracks or gaps found around windows or in crawlspaces. It might also be used to seal a new wall or addition to the house. It is most commonly used as a widespread insulation in newly constructed homes or more official buildings that use steel construction where owners are not as concerned with appearance as with utility.