The Dangers Of Pooling Water On Your Building's Flat Roof

The Dangers Of Pooling Water On Your Building's Flat Roof

20 August 2021
 Categories: , Blog


Flat roofing is the most common type of commercial roofing. Despite its popularity, flat roofing does have its complications. As a business owner with a flat-roofed building, you need to inspect your roofing regularly for signs of problems. One such problem that you may have with a flat roof is water pooling. It's important that you understand why this is a concern so that you can monitor for it and address it right away if you notice it occurring on your roof. Here's a look at some of the things you should know about why pooling water is problematic on your company's flat roof.

Coating Damage

Every flat roof is coated with a barrier product that protects the roofing membrane from deterioration caused by direct UV ray exposure, increases barrier protection against leaks, and more. That coating is an important part of your roof's structure. When water is left sitting on the surface of the roof as occurs with pooling water, this prolonged exposure to water can deteriorate the roof coating and leave your roof more vulnerable to leaks, deterioration from sun exposure, and more.

In addition, the areas where the coating deteriorates may actually appear discolored because of the difference in the roof condition. This can be unsightly in situations where the roof surface is visible.

Membrane Damage

When water is left pooling on your flat roof, the water will heat significantly from the direct sunlight and can concentrate the sun's rays, much like what happens with a magnifying glass. This results in intense sunlight concentrating on the roofing membrane, which can create weak points in the membrane. 

Eventually, these weak points can cause seams to fail and lead to cracks in the membrane itself. This leaves your roof vulnerable to leaks. In the winter months, repeated freezing and thawing of water that's pooling on the roofing surface will often cause the membrane to deteriorate as well.

Damaging Growth

One thing that many people don't think about when it comes to water pooling on flat roofing surfaces is the risk of fungus, moss, or other vegetative growth on the surface. Many types of vegetation can thrive in water, leading to growth in those areas where water sits on the roof. This growth can spread, causing structural damage to the roofing membrane and potentially to the underlayment and beyond.

Structural Weakness

If your flat roof has problems with excessive water pooling, you may find that your roof suffers structural weakness from the added weight. This is the same type of threat as you'd face with accumulating snow in the winter. The combined, prolonged effect of things like this could eventually lead to a roof collapse in the affected areas.

Reduced Insulation Benefit

When water has been pooling on the roofing membrane long enough to penetrate the surface, it will result in moisture damage to the insulation beneath your roof. When insulation gets wet, it deteriorates and loses a large portion of its insulating benefit. This will lead to increased climate control costs and problems with drafts and other types of discomfort.

Pest Infestation Issues

Water serves as a breeding ground for many insects, such as mosquitoes. Additionally, many pests will gather in areas where they have a water source, which can leave you struggling with pest infestations when you have water pooling on your building's roof. Eventually, those pests will find their way inside in search of food, which can be problematic for your building.

These are some of the concerns associated with pooling water on a flat roof. Reach out to a commercial roofing company, such as Drey Roofing, today to have your roof inspected and to look for any areas where water pooling could be a problem.