SPF is a resilient foam that can be used to close small to mid sized gaps and insulate large areas in new construction or renovation on the interior or exterior of a building. Sealing small gaps or entire areas with SPF can greatly increase energy efficiency.
Several types of SPF are known as two-component foam because the chemicals used to make the foam come in two separate containers. The chemicals are mixed together in a mixing chamber and are applied using a spray pump or spray gun. Generally, two-component SPF products fall into two main types, either low pressure or high pressure systems:
High-pressure systems can be used to spray all three types of spray polyurethane foam. Of the three types of spray foam used in building insulation and weatherization, the high-pressure, two-component spray foam is most likely to be used on larger projects such as a new building construction or renovations. SPF applied with a high-pressure system tends to adhere tightly to the entire structure which helps avoid sagging or detaching from its position. It can also provide a seal against air and insects.
Low-pressure spray polyurethane foam is typically applied around ductwork, electrical or piping penetrations, rim joists and roof repairs. This type of foam is used to insulate and seal small to mid-sized areas in homes and other buildings that are too large or extensive for smaller, insulating foam sealants. It is especially effective in weatherizing older homes that have many cracks, gaps and wall penetrations around doors, window frames, pipes and plumbing lines. The air- and heat-leakage improvements can be quite dramatic after a low-pressure SPF application, which can result in greater efficiencies.
Two component high pressure systems (usually 800-1600 psi) use drums for each component and are typically used to insulate large areas in new construction and renovations on walls and roofs. These systems are for professional use only. These systems also require special training and equipment including respirators.
Usually high pressure application is done with a spray truck that houses both parts of the foam, the air supply, and any other necessary items for a specific application. The truck is parked near the building where the insulation is being installed and hoses are run from the truck to the area to be insulated.