Here goes our first blog post for 2019, welcome aboard, we are glad to see you. Obviously, we hope you enjoy the blog posts but also it is our goal to provide you with worthwhile information.
The other day back in 2018 we talked about Spray Foam using a Foam Gun that is used to fill smaller voids. The purpose for that application is to stop Cold Air Penetration.
Today’s photograph shows a worker spraying Closed Cell Spray Foam over a large area. Today’s photograph clearly shows Spray Foam being used as insulation in an exterior wall. This type of application has several important characteristics:
- R-Values – typically Closed Cell spray foam has an R-Value of R-6.5 per inch of foam.
- Costs – an application of Closed Cell foam has a much higher insulating value than Fiberglass, R-6.5 per inch for foam v. R-3.5 per inch of fiberglass. However, foam costs considerably more! Costs for spray foam vary widely
Here at Vermont Modular we emphasize Energy Efficiency and Value. It is our opinion that the high cost of Closed Cell Spray foam restricts its use significantly in some applications.
We seldom use spray foam in exterior walls because of its cost. Even when cost is ignored the Thermal Bridging of the framing lumber is not effected; this causes us to recommend the use of Rock Wool insulation in the walls with Continuous Foam insulation on The Outside of a home. The Continuous Foam on the outside acts as a Thermal Barrier and the end result is a better insulated home for less money and therefore represents a Better Value.
The best way to build an exterior wall with the greatest insulating value is through the use of Structural Insulated Panels ( SIP ) where the framing lumber is completely eliminated by using the rigid foam sandwiched between sheets of sheathing. The obvious drawback of SIP’s is their cost.
Every building product has both advantages and disadvantages and Spray Foam is no exception. Each application, use, and the quality of the workers will impact the end product. Investigate carefully and thoroughly.
What do you think of spray foam?