Delaware Valley Corporation, responding to a request from a major single-ply roofing manufacturer, developed a felt cushioning material for EPDM and PVC roofing systems that allows the new membrane to go directly over bituminous roofs in roof replacement applications. Single-ply roofing has become a standard replacement for, and major improvement to, “built-up Bituminous Roofing”. It has become the roofing system of choice around the world for flat roofs on commercial and industrial buildings while making in-roads in residential applications under roof decks and on flat roofing surfaces.
The initial challenge was to separate the new single-ply membrane from the asphalt in the old built-up roofs that were being replaced. Without fully stripping an old roof, sometimes requiring roof deck replacement to remove any residue of the asphalt from the previous roof, there was the risk that trace asphalt would react adversely with the new single-ply roofing membrane, shortening the useful life of the new roof. The chemical process called “plasticizer migration” occurs when the asphalt from the old roof dries out the plasticizer in the new, single-ply roof causing it to become brittle well before its normal life.
Delaware Valley developed a felt for use as a separator/slip-sheet to allow the new single-ply membranes to be installed without a full replacement of the roof deck. Originally the felt was used as a separate layer requiring additional transportation, warehousing and labor to install the felt under the membrane. With ongoing research and cooperation with the Customer, the Customer has been able to incorporate our felt separator/slip-sheet into the original manufacturing process of the single-ply membrane by imposing the Needle Punched felt onto the PVC roofing membrane.
It is the collaboration with our customers from the initial contact through the customer’s product cycle life that Delaware Valley specializes in. Our approach is to constantly improve product performance and cost for our Customers, thus extending both our Customer’s lifecycle on their products and ours.