Advantages of Spray Foam Insulation
Polyurethane spray foam insulation is a very effective alternative to the more common fiberglass insulation traditionally used in home construction. Polyurethane spray foam insulation comes in 2 forms. It comes in an open cell foam as well as a closed cell foam.
Polyurethane was originally created by German chemists in the late 1930’s. By the early 1940’s it was brought to America where it was mainly used for military and aviation purposes. It wasn’t until the 1960’s that technology was created that allowed Polyurethane to be used for insulation within home construction.
Components of SPF
Spray Polyurethane Foam SPF in the result of mixing 2 chemical compounds together; isoncynate (A) and polyol (B). Side A consists of
Polymeric MDI, Methylene diphenyl diisocyanate.
Side B usually consists of
- polyol –(derived from petroleum and agricultural sources)
- Flame retardants
- Blowing agents
- Amine or metal catalysts
The A and B components are then carefully formulated to meet the requirements of the specific application. To create the proper mixture, the A and B formulas are pumped through positive displacement proportioning pumps. From the pumps the formulas are sent through heated tubes then to a mixing- spray gun. The material is them applied to the designated surface.
Material Safety Data Sheets (MSDS) are available for both “A” and “B” side chemicals. Your contractor can provide these to you at your request to inform you of the chemicals being used within your home.
Chemical Reaction & Application
Once the heated material is applied, gas is formed by the quick chemical reaction between the materials, creating millions of minute bubbles, or cells which then expand the SPF as it forms into a rigid polymer. The SPF professional will then control the thickness of the SPF material as it is applied to address a specific R value.
Properties of SPF
Since SPF is applied first in its liquid form and then quickly expands, this allows the product to fill all voids and fully adhere to the applied surface and create a seamless, monolithic application.
This quality gives SPF the following advantages in insulating your home;
- Prevents air gaps and void spaces- SPF virtually eliminates all gaps and air spaces which cause heat loss and inefficiencies in insulation.
- High R value insulation- closed cell SPF has very high insulation values. Refer to chart for more information.
|Closed Cell SPF||Open Cell|
|Higher R- value (greater than 6.0/ inch)||Lower R- value (approximately 3.5/ inch)|
|Impermeable to air||Impermeable to air at full wall thickness|
|Impermeable to moisture yet allowsslow diffusion of water vapors||More impermeable to moisture and less permeable to vapors|
|Provides strength and rigidity||Lower strength and rigidity|
|Provides sound attenuation||Provides exceptional sound attenuation|