The Effects of Ponding Water on a Flat Roof

Ponding Water on a Flat RoofPonding water can occur in any type of roof. This can lead to all sorts of problems, ranging from leaks to mold buildup. Ponding water on a flat roof is especially common. We’ll explain why this is so and what you can do to remedy the situation.

What Causes Ponding Water on a Flat Roof?

Ponding water is defined as a puddle that remains on a roof for more than 48 hours. Ponding is especially common on commercial roofs, since these tend to have flat surfaces as opposed to residential roofs with a triangular slope.

There are two causes of ponding water on a flat roof: building degradation and deck deflection.

Building Degradation

Flat roofs contain multiple layers of hot asphalt, roofing paper, and gravel. The gravel is the uppermost layer. This is also the part that erodes over time due to sunray exposure. The eroded gravel creates a recessed area that enables water to accumulate.

Deck Deflection

Deck deflection occurs as a result of excessive rainfall. The weight of the water taxes the support beams, causing them to bow downward, thus forming a declivity. Once again, this creates a recess that enables water to accumulate. Deck deflection often occurs right in the center of the roof.

Once the water evaporates, the beams may return to their original position. However, the declivity may become permanent if deflection occurs frequently.

Aside from rainfall, deflection may also occur as a result of uneven weight distribution of heavy structures, such as an HVAC system.

We’ll Fix Your Flat Roof to Prevent Ponding Water

Call Urbizo Bros Roofing so we can inspect your roof and determine if it’s vulnerable to ponding. Don’t wait until water actually begins collecting on the surface to take action. Our services include remedies for preventing water ponding on a flat roof.

Edited by Justin Vorhees

Flat Roof Repairs to Keep Ponding Water at Bay

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