Ask An Expert: What is a PVC roofing system?

At Jewett Roofing, we are dedicated to making sure our customers are educated on all parts of their roofing project.

taken the time to answer some of our most frequently asked questions from our industry. Get insights on PVC roofing, EPDM roofing, and roof coating solutions through our Ask an Expert segment.

What is a PVC roofing system?

PVC is Polyvinyl Chloride. It is one of the most widely used plastics in the world, and is used in countless building products.  It is very rigid in its natural state but can be made pliable with the addition of plasticizers. PVC is defined as a thermoplastic as opposed to a thermoset material.  This means that when it is heated, it turns to a liquid and then hardens when cooled. This process can be done again and again with very little chemical degradation, which is what allows PVC roofing materials to be welded together.  

In roofing applications, sheets of PVC are mated with reinforcement layers that add dimensional stability and strength.  This material is then manufactured into rolls which eventually become the roofing system. Simply stated, the system is all of the components that make up the finished roof. They vary greatly from building to building, but there are some general commonalities.  

Starting at the roof deck they typically consist of:

  • Insulation layer
  • The material (waterproofing layer)
    • This includes a way of attaching the material to the roof.  
        • Mechanically fasten (screws)
        • Ballast (piling rocks on it)
        • Fully adhered (gluing it down)
  • Penetration flashings
  • Edge Detail

This is a highly simplified version of a “roofing system.” For each of the different products, the components, as stated above, are pretty similar, but how they go about producing the material or penetration flashings is where the differences happen.  For example, some manufacturers produce the waterproofing layer in deck sheets up to 2500 square feet to the exact size and shape of the building, while other’s sell it in rolls 3’, 5’ & 10’ wide. Some manufacturers produce penetration flashings to the ¼” to fit each pipe and unit, while some have the contractor fabricate the flashing on the roof.  Each of these methods has its own benefits.

If you have any other questions about PVC roofing, contact us today!