Clogged Drains and Debris Build-up on Flat Roofs

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Published: August 13, 2014 Last Updated: November 19, 2014

Flat type roofs often have leaves and other debris that gathers on them overtime. If the leaves and debris are not occasionally removed, the drains may get clogged or restricted by the debris. If water builds-up, leaking may occur and if the water builds up high enough, it can cause structural damage.

Clean from time to time 

It is wise to check the roof periodically to see if there is any build-up occurring. Flat type roofs with a curb should have secondary over flows, so if the primary one clogs up, stuff can get off the roof through the secondary over flow. Check these secondary overflows to make sure that they are clear and free flowing as well.


Drains that run through a curb or wall on the edge of a roof are often called scuppers.

They are usually metal or molded plastic. Check these to insure that they are not clogged and that debris is not over or in front of the scuppers.

Interior drains

Roofs may drain over the edge, they may drain into gutters and down spouts, or they may drain into pipe (drains) that go through the interior portion of the home or garage.

Keeping these drains free flowing should be thought of as being part of a homeowner’s maintenance program.

Tip: If you have a flat roof with curbs, ask your inspector if there are secondary over flows in case the main one gets blocked. Having a secondary overflow for flats roofs with a curb is desirable.

Who to consult? Handymen or roofer.

Roofers or handymen generally do maintenance on roofs. In most circumstances a home owner can likewise do these type of maintenance items as well.

Additional Resources

  • My kids were always putting toys and rocks in the drains. If a drain is clogged, first start...

  • Blisters on a flat roof may result in leaking if they get popped. Just stepping on them when doing work or maintenance on the roof may pop them.

  • Deterioration or leaking may occur if water stands on a roof too long. A little puddling is acceptable provided that it is not too deep.

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