What is PVC Roofing?

Posted on: March 4, 2021
Single-Ply

First used on commercial buildings in Europe in the 1960s, Polyvinyl Chloride (PVC) membrane roofing has been in wide use here in the United States since the 1970s. Stronger and more durable than other types of single-ply roofing, PVC roofing is valued for its resistance to chemical and fire damage, as well as its UV resistance and energy efficiency.

While certainly not the cheapest roofing option for flat or low-sloped commercial roofs, PVC may be ideal for applications with higher chemical and weather exposure, especially in mild to warm climates. Consider the following when deciding whether PVC the right choice for your next commercial roofing project.

What is PVC Single-Ply Roofing?

PVC roofing is a thermoplastic membrane made from an ethylene-chlorine polymer (known in laymen’s terms as vinyl or plastic). PVC is generally rigid and firm in its standard form, so plasticizers are added to make the PVC flexible enough for roofing applications. A polyester or fiberglass scrim is added to increase its tensile strength durability. PVC roofing comes in various colors and is particularly useful when the roof is regularly exposed to heat, chemicals, harsh weather elements, and high winds.

How is it Different from TPO Roofing?

While both PVC and TPO are thermoplastic membranes great for energy efficiency and UV resistance, from a chemical standpoint, think of TPO roofing as rubber-based and PVC as plastic-based. TPO is more affordable as an all-around roofing option, and it tends to hold up better than PVC in colder climates. However, PVC tends to have a longer service life and is generally considered more robust against the elements.

Pros and Cons of PVC Roofing

Every commercial roofing type has its advantages and disadvantages, so not every commercial roof is made from the same material. When considering whether PVC roofing is a good option for your project, consider the following pros and cons.

Pros of PVC Roofing

  • Highly durable.PVC is among the strongest types of single-ply roofing materials available on the market today, able to withstand extreme conditions and moderate foot traffic without damage.
  • Resistant to the elements. PVC roofing provides outstanding waterproofing protection and can also hold up against high winds, making it an excellent choice for commercial buildings in areas prone to severe weather (especially hurricanes). It is also highly resistant to natural deterioration agents like mold and algae.
  • Fire-resistant. PVC is extremely difficult to ignite and slow to burn, even when exposed to extreme temperatures. This quality makes PVC a great choice for restaurants or other industries with high-temperature applications.
  • Chemical resistant. PVC is a highly stable compound that doesn’t deteriorate easily when exposed to toxic or corrosive chemicals. This makes PVC an excellent choice for manufacturing plants or other industries with frequent exposure to chemicals.
  • Energy-efficient. PVC roofing resists UV rays and reflects the sun’s rays for a “cooling” effect, making it easier to keep the building cool in summer and lowering energy bills.
  • Lightweight. Pound per pound, PVC roofing affords outstanding protection without putting undue stress on the building’s structure.
  • Long service life. PVC roofing has the longest life expectancy of any other type of single-ply roofing system.

Cons of PVC Roofing

  • Higher cost. PVC is more expensive per square foot than other single-ply membranes.
  • Poor response to cold temperatures. Despite its overall flexibility, PVC roofing tends to become brittle in cold climates and may crack and cause leakage.
  • More difficult to maintain and repair. When damage occurs, PVC is challenging to repair, and in extreme situations, the entire roof may need to be replaced.

How is PVC Installed?

PVC membranes can be installed over the roof deck in one of three ways:

  • Ballasted installation. The membrane is laid out loosely over the roof deck and held in place by ballasting material (e.g., gravel).
  • Mechanical attachment. The membrane is fastened directly to the roof substrate with a series of heavy screws and plates. This form of installation adds additional stability and is often recommended for hurricane-prone areas.
  • Fully-adhered installation. The membrane is attached to the substrate using an adhesive, either applied to the substrate or by self-adhered PVC sheets.

Regardless of the installation method used, the PVC is usually laid out over an insulation layer placed over the roof deck (typically ISO or EPS form boards). After installation, the seams are welded together with a hot-air gun, and flashing is installed to prevent leakage at prone areas of the roof.

Maintenance Needs

To maximize the life expectancy of a PVC roof, it should undergo a regular maintenance routine. PVC roofing can be cleaned at regular intervals using a low-power washer (never a high-powered one) and a mild, non-abrasive detergent. You should also check the seams and flashings for signs of wear and deterioration and reinforce these as necessary.

Expected Longevity

With proper care and maintenance, a properly installed PVC roof should last at least 20 years — although they have been known to last as long as 30 years before needing to be replaced. The life expectancy can also be affected by other factors: As previously mentioned, PVC roofs tend to do more poorly in freezing temperatures. Repeated damage events may also hasten the need to replace the roof. Finally, not all PVC roofing manufacturers have the same quality control standards, so make sure the manufacturer is a trusted brand with a good track record to increase the chances of good longevity.

There are many different types of PVC roofing available, along with other commercial roofing options, and the choices can be confusing. Working with manufacturer representatives like RoofSource can improve your chances for a positive installation experience. We represent some of the most reputable manufacturers in the commercial roofing industry. Our team of experts can help you evaluate your situation to develop a perfect solution for your project’s needs. Contact us today to get started.