PVC Flat Roof Repair and Replacement

PVC is a flexible, thermoplastic membrane manufactured using UV-resistant polyvinyl chloride. PVC is often thought of as plumbing pipes, but this versatile plastic can also be very affectively used on flat roofs. As a roofing material, the plasticized attributes help lend it a strength that can help make the roof more durable and lower maintenance than similar materials.

Like EPDM, PVC is most frequently used on larger roofing jobs. Seams between PVC sheets are welded together with a hot-air welder. This ensures superior seam strength and makes the membrane resistant to leaks and wind blow-off.

One benefit of installing PVC roofs in Minnesota is that PVC roofing can be installed year-round. Since the temperature of the heat welded seams is critical to getting a strong bond, we adjust our welder temperatures upwards in the winter to compensate for cooler ambient temperatures. Welding PVC seams relies heavily on the craftsmanship of the roofing professional to achieve the correct temperature, pressure and speed required for a perfect weld. The advantage of hot-air welding a PVC roof compared to solvent based glued seams is you don’t have to deal with the seam adhesive freezing, which can making installation or repair problematic.

PVC roofs that are installed with welded seams are stronger than the material itself, plus PVC membrane is impermeable to moisture and offers excellent long-term durability. The membrane is armored with synthetic threads, so even after 30 years it still remains flexible and easy to weld to, making it easy to patch and maintain. Because PVC roofing is naturally white, it has outstanding heat-reflective qualities without needing any additional coating or extra treatment.

Methods of Adhering PVC Roofing Membranes

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1. Fully-Adhered Roofing System
2. Mechanically-Attached Roofing System
3. RhinoBond Roofing System
4. Ballasted Roofing System

PVC Cost: The total cost on average is $7 to $13 per square foot. A typical assembly includes the same elements as the above membranes, as well as attachment, except PVC can be ballasted with river rock if a protection mat is used, but the seams are all welded, all the time. There is no use of primer and pressure sensitive tape. The metal at the perimeter edges (if attached to the membrane) must be PVC coated, but can be painted or have a two piece metal detail to have colored perimeter edges. The advantage of PVC is the monolithic membrane, colors that are candidates for energy company rebates, and a longer history than TPO. PVC roofing membrane is more resistant to chemicals and oils than other flat roofing materials. The disadvantages are installation requires the use of more expensive coated metal, its hail susceptibility, and the limited availability of colors.

These prices would not include insulation to code. For example, if the R-value for a typical home is R-38, the requirement would be more than 6 inches of insulation. Most structures in Minnesota already have some insulation, so the price would be based, on the additional insulation required.

These prices fluctuate in terms of size and difficulty, and may cost more than noted above. Very small and difficult projects are more expensive, due to greater labor and possibly added material costs. With any of these membranes, more penetrations add to the difficulty and to the final cost. The cost is dependent on the amount of detail work required.