There are two main types of spray foam to consider: open-cell and closed-cell. Open-cell spray foam has a lower R-value per inch and because of this, typically a lower price tag. The soft, low-density material is used for interior applications. Its high permeability allows for moisture to pass through, which contributes to bi-directional drying of the assembly, but it may not be ideal for all applications or climates. 
For example, a hybrid solution of spray foam and fiberglass batts or rolls combines the air-sealing and vapor-retarder benefits of foam with the economical thermal performance of fiberglass. Another option might be to install spray foam in places that are hard to reach or seal, such as rim joists, the attic floor, and eaves, and then install fiberglass batts and loose-fill in the in the open areas, greatly reducing any draftiness while helping the project budget. Incorporating spray foam into hybrid solutions enhances the building envelope and seals efficiently at a reasonable cost.
Closed-cell foam has a higher density and offers a higher R-value per inch. It also adds strength to walls, ceilings and roofs and can contribute to a structure’s overall durability. Additionally, closed-cell foam’s low water vapor permeability offers protection from moisture when installed in places where high humidity—from climate, occupants, or flooding—meets the structure. 
Open-cell is also known as half-pound foam. It has an R-Value of 3.5-3.6 per inch, and its density is bout 0.5 pounds per cubic food. Low-density foams like these are made partially from raw biological materials Carbon dioxide or water is also used in the makeup. Open-cell uses far less material than closed-cell, but its R-Value is lower. Also, open cell requires a vapor retarder (like gypsum wallboard) and is riskier when used for roof sheathing. It's not highly recommended that you use open-cell insulation if you live in a cold climate unless you have that extra barrier. You should also compare how much money you spend versus how effective the open-cell insulation is wherever it's installed.
Determining which type of SPF is right for the project involves evaluating the application area, overall budget, and scope of a project. Review insulation needs in attics, walls, ceilings, and other areas, and account for factors like project location, climate and how the building will be used. For example, an indoor swimming pool will drive towards a different SPF selection than an office building. 

How Much Is Spray Foam Insulation For Attic

Spray polyurethane foam, or SPF, is the main type of 2-part, closed-cell spray foam used by insulation contractors. Large-scale insulation jobs require special equipment as well as safety gear to protect the installer from chemical fumes during installation. When the foam cures and hardens just several minutes after application, it's completely safe for as long as it stays in place.
The United States has adapted to using sprayfoam insulation and a new technology called Wall Injection to retrofit existing wall construction by drilling small holes between wall studs in the structures framing and filling the void with a less aggressive expanding water based foam. This allows existing home and business owners to conserve energy by creating a thermal envelope in their existing structure.

Roof Coating Seal