Spray Polyurethane Foam (SPF) Basics

      Whether you're retrofitting an existing home or creating a new one, insulation is an important consideration; and spray polyurethane foam (SPF) insulation is among the best ways to increase energy efficiency and improve comfort.

       There are various aspects to consider when deciding the type of spray foam insulation to utilize for your application. Density is one such factor. When it comes to spray foam insulation, there are three main density levels to choose from: high-density spray foam insulation, medium-density spray foam insulation, and low-density spray foam insulation. Each spray foam density is tailored to a specific application and provides distinct benefits. As a result, it's critical to become acquainted with the various densities in order to select the appropriate spray foam insulation type for your project. Here's a breakdown of the differences in spray foam densities to help you choose the correct one for your project.


       All spray foam insulation types have a denser structure than high-density spray foam insulation. More material is required to cover and insulate an area due to its high density. Closed-cell foam weighs about 3 lbs. per cubic foot of high-density spray foam insulation. Because of its denser structure, high-density spray foam insulation does not expand as much as lower-density foam. High-density spray foam has an R-value of roughly 5.5 per inch.



       The application of high-density spray foam is continuous, resulting in a flawless finish. High-density spray foam insulation can dramatically cut energy expenses inside a structure during the lifetime of the roof it is applied to, thanks to its excellent thermal resistance capabilities.

       High-density spray foam insulation can help protect and extend the life of roofs and exterior structures in addition to providing excellent insulation. High-density spray foam insulation, once adhered to a surface, can help prevent wind damage by enhancing the structure's resistance to wind uplift. It also serves to protect the roofing from heat and water intrusion while also strengthening and supporting the structure to which it is applied.




       Around 2 lbs. of closed-cell spray foam per cubic foot is required for medium-density spray foam insulation. It has a high R-value, which starts at 5.7 per inch and goes up from there.

       Medium-density spray foam insulation can be applied as a low- or high-pressure two-component spray foam, depending on the application. Medium-density spray foam will most likely be applied as a high-pressure, two-component spray foam for major projects like renovations or new construction. Medium-density spray foam is often applied as a low-pressure, two-component spray foam for insulating small to midsized areas such as around ducting or plumbing.



       Medium-density spray foam insulation has high tensile strength, meaning it can resist a lot of stress without breaking, which is ideal for applications that require a long-lasting insulating solution. In addition, medium-density spray foam insulation has a strong bonding ability. To put it another way, medium-density spray foam insulation sticks strongly to the surface it is applied to and requires a significant amount of force to separate it from its foundation.

       In addition, medium-density spray foam insulation has a low vapour transmission rate. As a result, when exposed to damp surroundings or rain, its insulating properties are usually unaffected.




       Low-density spray foam insulation, also known as open-cell foam or half-pound foam, uses about 0.5 lbs. of open-cell foam per cubic foot. This insulation material has a lot of open cells on purpose, which makes it softer, less dense, and more flexible.

       Low-density spray foam insulation has an R-value of around 3.6 per inch. Low-density spray foam insulation, like medium-density spray foam insulation, can be applied as a two-component polyurethane spray foam at low or high pressure.



       It's a good insulator as it offers the surface it's applied to, continuous insulation and an air-sealing barrier. As a result, airflow through joints, seams, fractures, and cavities can be efficiently blocked. While low-density spray foam insulation works as an air barrier, its open-cell structure allows moisture and vapour to pass through. Low-density spray foam insulation helps ease moisture management and bi-directional drying when needed by allowing for moisture permeability.





       THE DIFFERENCE BETWEEN SPRAY FOAM DENSITIES (2020, April 14). Paragon Protection. Retrieved from: https://www.paragon-protection.com/the-difference-between-spray-foam-densities/