What is the function of a 1/4″ DensDeck overlayment board?
When 1/4″ DensDeck is used over insulation and underneath a membrane, it is referred to as overlayment. It is also called a recover board. There are two main functions of 1/4″ DensDeck overlayment. First, it delays the passage of fire or the transmission of temperature to the roof insulation and the rest of the roof assembly when fire starts outside the building. The other function is to provide a versatile surface for the application of the membrane. When roofs are recovered, the existing roof system is left in place (reroofing, on the other hand, involves tearing off the existing roof system to the deck assembly then installing a new roof). The new roof is applied after a “recover board” is installed to act as a membrane substrate. Recover boards must be able to withstand potential water entry, temperature extremes and maintain compressive strength. They also must possess excellent fire properties to achieve a Class A rating. 1/4″ DensDeck offers all these features. UL Class A, B, C
