How to Drain Water From a Flat Roof And Prevent it From Happening

How to Drain Water From a Flat Roof

If your home or business has a flat roof, you are probably only all too aware of the issues of water pooling on it. If an excessive amount of water builds up due to poor drainage, it has the power to threaten your roof. It can lead to your roof leaking and even cause structural damage, such as sagging. It is important that water does not remain pooled on the roof for more than 48 hours because the roof will become compromised. 

Why is draining the roof important?

There are several reasons for this, including:

  • As already mentioned, pooling water can lead to leaks and structural damage.
  • Twigs and debris can accumulate on the roof.
  • The debris and twigs can damage the tar and caulking on the roof.
  • In winter, there will be excess damage caused by freezing conditions and ice.
  • There will be leaks near features too, like the chimney or heating and cooling units.
  • Plantlife may be encouraged to grow.
  • Bugs and mosquitos could be attracted to the water.

How to drain water from a flat roof

Here are some methods to ensure that your flat roof drains water.

  • You can use interior drains, positioned where the water pools on the roof. Water is encouraged to travel down the pipes to the gutter.
  • Gutters are attached to the edge of the roof and redirect water away from the side of the building where damage can be caused.
  • Scuppers are where square holes are on the side of the wall with a little funnel where water is shot away from the side of the building.
  • You may initially need to get out there and brush it off with a broom or use some suction device before you fix the problem.

How to prevent water from pooling on a flat roof 

If you have had an issue with water pooling on a flat roof you can have it fixed in a number of ways to prevent it from happening in the future:

  • Ensure any low spots where water pools are repaired. You can do this by filling in the low spot with roof plaster to make it level with the rest of the roof. Bearing in mind flat roofs do have subtle slopes to ensure water flows towards the drainage system A professional roofing contractor is able to do this for you.
  • It is a good idea to open up and/or unclog the existing drainage system. Over time leaves, and other debris can build up and cause a drainage issue causing water to pool on the roof. Having a regular cleaning of drains and gutter is essential for roof health.
  • Invest in more drains and gutters. If the areas you live in have a lot of rain or more rain than it used to, it may be an idea to install more drains to remove the water from the roof. Alternatively, you could make the current system wider to allow more water to flow off the roof.
  • The roof may need repitching if it was not done correctly the first time. This means that the subtle slope was simply not done well enough and doesn’t let water flow off the roof. This can be quite a complicated task, so it is best to speak to commercial roofing professionals.

Now that you have a better understanding of how to drain water from a flat roof and prevent it from happening you should be good to go, but if you need any help and you’re in Portland or the Greater Northwest we’d love to serve you! We provide flat roof maintenance and commercial roofing services in all of NW Oregon & SW Washington. You can get in touch with us at (503) 659-7663 for all your roofing needs.




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