Phenolic Roof Insulation

The phenolic foam roof insulation turned out to have a critical flaw.

Phenolic roof insulation.

It offers many advantages including excellent density and an r value of 4 8 per inch of thickness which forms an effective barrier against heat transfer and thus helps you save energy around the house. Phenolic foam insulation used to be available in board form but today is only sold as a type of foamed in place insulation. Phenolic foam insulation was a short lived innovation developed in the early 80s in response to the energy crisis driven demand for greater insulation efficiency. When it was installed over a lightly primed painted metal deck any water in the roof system from above moisture from operations or humidity within the building activated chemicals in the phenolic foam which caused corrosion of the metal deck.

The reason is that phenolic dust once introduced to moisture can become very acidic and damage surrounding materials. Phenolic foam insulation was manufactured and sold into the north american market in the 1980 s and early 90 s mainly as roofing insulation. It is important to note that the coatings used to paint corrugated decking are applied at a thickness of between one half and. Phenolic insulation exposed to humidity or direct moisture such as roof leaking creates sulphonic acid.

In a short amount of time this sulphonic acid corrodes both standard painted deck as well as galvanized deck. The presence of phenolic insulation should be carefully considered. High moisture absorption potential and residual acid present in the foam allegedly resulted in significant corrosion issues.