Spray foam is the result of a chemical reaction. Two liquids combine to make foam, which then expands within the walls, crawlspaces and crevasses of a home or commercial building. In particular, one chemical is methylene diphenyl diisocyanate (MDI) and the other is a blend of polyols, catalysts, blowing agent, flame retardant and surfactant.
Well, let’s first ask these questions – do you want to save energy and money? Do you want to reduce allergens in your home? Do you want to protect your home from mold and mildew? Do you want to reduce drafts and changing air?
If you answered yes to any of those questions, and hopefully you answered yes to all, then you’ve realized the need for spray foam insulation.
Spray foam insulation is the only insulation available on the market that does everything listed above and more. While it is relatively more expensive than your traditional fiberglass insulation, the investment is worth every penny.
R-value is a measure of thermal resistance. It’s a measurement of how effectively a certain material can resist conductive heat transfer. A loose or porous material will have a low R-value, while a strong and durable material will have a high R-value. A lower R-value means the material allows for heat transfer more easily, while a higher R-value means a material is more resistant to heat transfer.
R-value is the reciprocal of U-factor (also known as U-value). U-factor is a unit of measurement describing how well a certain material conducts heat, while R-value is a measurement of how well a certain material resists heat conduction.
Since spray foam is available in two particular forms – closed and open-cell – there are two different R-values accordingly. The r-value for closed-cell foam is in the 6.0 range, while open-cell foam is more around 3.5 or 4.0.
How does that r-value compare to traditional fiberglass batting? Well, fiberglass batting has an average r-value of 2.5. As you can see, spray foam insulation has a greater resistance to heat transfer.
However, we want to make mention that r-value isn’t everything. Why? Because a contractor can pack fiberglass batting and achieve a higher r-value without ever achieving an airtight seal.
The difference with spray foam is all in the air tightness. Spray foam provides great resistance to heat transfer but also keeps all walls and spaces airtight and away from the changing outdoor elements. This saves you more energy and keeps your home or building safer in regards to damaging agents like mold and mildew.