While closed cell spray foam insulation is the best way to insulate and air seal a home, there has been some push back on the use of this product by environmental experts and activists. Why? Most spray foam insulation types are petroleum based, made primarily of polyurethane compounds in a semi liquid state. Typically, spray foam insulation comes in an A and B component cylinder or barrel. The two component types make one set of foam that is able to be sprayed. When the two compounds mix together in the spray foam gun, a chemical reaction takes place that produces heat and causes the spray foam to expand and harden. What is different about the soy foam? Nothing except that the sets of foam are made of soy bean oil rather than polyurethane.
Soy Based Spray Foam
Soy based spray foam is a closed cell spray foam product that has an average R-value of R-7 per inch applied at an average density of 1.8 lbs per cubic foot. This happens to be exactly the same as polyurethane spray foam products that insulation companies have been spraying for years. The soy bean oils are extracted and synthetically altered in order to create the same effect as polyurethane foam when the A and B side compounds mix. This material is considered greener because the compounds produced are straight from planted fields.
As with many bio based products, the major drawback of soy based spray foam is the inconsistency of the end product. Soy spray foam is supposed to harden completely when cured and create, not only a perfect seal, but as close to perfect thermal barrier as possible. When the soy compounds are inconsistent, the foam does not cure as well and the R-value and the density of the product is diminished. This variable is because the oils used to make the foam are natural and cannot be reproduced exactly the same every time like petroleum. This inconsistency is one of the reasons that this product has not taken off past polyurethane spray foam insulation.
There is a large amount of people involved in the production of soy based spray foam. So many, in fact, soy based foam may actually be worse for the environment to produce because of the long supply chain that is involved in making this soy bean oil into usable sets of spray foam. While there is no conclusive evidence or data of this, It is a noted concern of bio based products like soy based spray foam.
Soy based spray foam is a great green alternative to polyurethane spray foam insulation. Even if the consistency of the material is slightly less, this is not likely to make a significant difference in energy savings over the life of a home.