The term ‘flat roof’ is actually a misnomer, as flat roofs must have some slope to drain properly. But even with a slight slope, drainage can be an issue.
We’ve put together a list of the most common flat roof drainage issues, their causes, and how to fix them.
Common flat roof drainage problems
Ponding, or the pooling of water on your roof, is a sure sign that you have a drainage problem. If the water stays on your roof 24-48 hours after rain ends, you may have one of these common flat roof drainage issues:
- Clogged drains
- Inadequate roof slope
- Insufficient number or size of drains
Not addressing these issues promptly can lead to additional damage, including roof leaks, structural damage, and the growth of mold and mildew, which can reduce the lifespan of the roofing material.
Clogged drains
Depending on your roof design, you may have traditional gutters and downspouts or rain drains that are plumbed into a storm drainpipe. Anytime these drains build up with debris such as leaves and branches, roof drainage can be affected. This leads to ponding, which can compromise the structural integrity of your roof and potentially cause leaks or damage the roofing material.
Inadequate slope
If your flat roof isn’t sloped steep enough to ensure that water moves to the drains, it can cause a backup. Additionally, if there’s structural damage to your roof, caused by foot traffic or the heavy weight of water, snow, or equipment on the roof deck, this sagging can lead to water accumulation.
Insufficient drainage
If area roof drains are improperly located or there aren’t enough of them, water accumulates on the roof, causing potential leaks and structural damage.
Consequences of Not Fixing These Issues
The consequences of not fixing your flat roof drainage issues can be serious. Over time, ponding water and lack of drainage can lead to:
- Reduced roof lifespan – The continuous presence of water on your roof can break down the roofing material, shortening its useful life. This could lead to the need to replace it sooner, thereby increasing costs.
- Roof leaks – Water will find its way into cracks, seams, or other vulnerable spots on your roof, potentially damaging the interior of the building and its contents.
- Structural damage – Water is heavy and can weaken your roof’s structural integrity and compress insulation. Repairing these issues can be costly and may require replacing the entire roof.
- Mold and mildew growth – Mold and mildew growth on the roof can infiltrate the building, causing respiratory problems and health concerns for the occupants. Additionally, remediation is costly and takes a lot of time.
How to fix flat roof drainage problems
If your building has clogged drains, gutters, or downspouts, they should be cleared regularly as part of building maintenance. You should test your drainage system as part of your twice-a-year roof maintenance inspections. Drains may need to be cleared more frequently if debris buildup is a problem.
Problems caused by inadequate slope and insufficient drainage are more difficult to address because you may end up having to replace your roof. A professional roofer should inspect the slope and drainage system to determine the best course of action. Options include adding additional drains at roof low points, fixing structural issues, adding tapered insulation, and increasing the roof slope.
No matter what your flat roof drainage issues are, the team at New Roofs Inc. is here to help. Leaving things alone can lead to more expensive repairs or roof replacement. Reach out today for more information.