PVC Flat Roof Installation

PVC Flat Roof Installation

PVC Flat Roof Installation

There are many different types of flat roofs, but the two main types are PVC (vinyl) and TPO (thermal plastic). At Pro Roofing NW we prefer PVC over TPO because they are more water resistant - which is a must in the rainy Seattle climate. However, TPO is considered a "greener roof" option because it emits less gas when welded together. Flat roofs are notorious for being costly to upkeep due to their predisposition for springing leaks. However, PVC flat roofs are so watertight that even if water pools on your roof for an extended time it should not have adverse effects. PVC is also known for its strength - these types of roof can last more than 20 years!

Flat Roof Underlayment - What You Need to Know Before Hiring a Roofer

One of the most important parts of flat roof installation is the underlayment. Because Seattle is such a rainy climate, one of the most important things you should know is that when choosing a roofing material is that you should never install a single ply roof (such as torchdown). The biggest problem with single-ply roof types is the risk for condensation. Over time moisture from inside your home from normal activities (showering, boiling water, breathing, etc.) will begin to accumulate in your attic and under the single ply membrane. Condensation will manifest itself just like a leak, but it's just water from inside your home that is trapped and can't get out. To ensure this doesn’t happen to you it is imperative your roof has two proper layers of underlayment as well as proper venting. Every PVC roof must have both layers of protection under PVC.

Two necessary layers of protection for your flat roof include:
  • Leak barrier - In order to protect your flat roof it's important to have a leak barrier that acts as a shield from water and ice. These barriers allow small amounts of water vapor to evaporate through them from the inside of your home but will not allow water drops from rain to pass through to the inside of your home.
  • Separation sheet - Additional protection for your flat roof includes the installation of a separation sheet. These sheets are felt-like and applied directly over the leak barrier. They will absorb small amounts of moisture under the membrane in case any water passes through the leak barrier.

Venting for Flat Roofs

The next important thing to consider during flat roof installation is proper ventilation. There are two basic types of vents - one lets the air out of the attic (RVO) and the other pushes air under the membrane and over the separator sheet to dry it (soffit).

  • RVO high neck vents - These types of vents are used to let air out of attic cavities. The necks are tall because water can build up and run into the house through the vents.
  • Soffit vents - are installed on the underside of your home's eaves. Cool, dry air enters through these and then get pushed up and out through the RVOs.

Why Choose Pro Roofing NW?

Flat roofs are more individually unique than any other type of roofing. Pro Roofing NW has years of experience in providing these roofs in the rainy Seattle climate and can help guide you through the process as well as ensure that adequate measures have been taken to prevent future leaks.

Questions about flat roof installation? Contact Pro Roofing NW to request more information and a project estimate.
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