Commercial Roofing Drain System

Everything You Should Know about the Roof on Your Building
February 1, 2019
Everything You Need To Know About Commercial Roofing
February 8, 2019

The sun and high amounts of rain we get in this area takes its toll on commercial roofing. A commercial roofing system needs a complete and properly built draining system. Just cleaning your gutters is not enough to drain the rainfall in this area. If your system is not complete and working together as it should, rainwater runoff will end up inside the roof deck, your building, or worse, your inventory.

Edge and interior systems

Although there are some differences in low-slope roofing, the systems almost always drain at the edges and across the roof expanse. The different type of Edge drains include:

  • Gutters – Channel made of metal that carries water from the roof to the downspouts.
  • Scuppers – Holes in the parapet walls which help water drain off the roof.
  • Secondary scuppers – These holes are higher up to help drain water when the primary scuppers get clogged.
  • Downspouts – Both gutters and scuppers drain water to downspouts, which carry that water to either a basin or the local water system.

When it comes to large roof expanses, Interior drains are necessary to handle the water. Most “flat” roofing systems probably have four segments that slope toward an interior drain with a strainer. This type of drain actually empties into your building, carrying water through a drain that eventually empties into a standpipe.

Proper draining

Water will back up and form a pond when your strainers and scuppers clog, whether your commercial roofing system has scuppers, interior drains, or a combination of the two. If the ponding is bad enough, small trees can actually begin to take root. Water infiltration can result because of the weight and organic matter build-up on the roof.

Contact your professional roofing contractor to make sure you keep your roof draining as it should. Clogs and ponding can be prevented with regular maintenance and inspections. Water weight on your roof can build up significantly around a circular strainer that has just a small amount of debris damming it.

Roofing problems

Your original roof design probably did not include future add-ons like skylights, satellite dishes, HVAC units, etc. These items, which were probably not anticipated by the architect who designed your roof, can affect the draining system, trapping and holding debris on your roof. Your commercial roof may need an interior drain system installed or another method that can divert water around these new roof additions. A reputable commercial roofer can inspect your roof and help you decide on the best course of action for your situation.