4 Consequences of Ignoring Ponding Water on Your Flat Roof

Ponding is the occurrence of water pooling on flat roofs after storms, snow melts, or heavy rains, but do you know about the types of damage that water is causing when left unrepaired?

Roof systems are simply not designed to hold water. Even “flat” roofs contain a slight slope to maintain positive drainage. Ponding water is typically a sign of a drainage problem that needs to be addressed, because when left unaddressed, ponding water on a roof can:

• Collect dirt, which may cause the growth of vegetation or telegraph mud cracking to the roof below.
• Act as a magnifying glass on the roof under the pond, which increases the damaging ultraviolet exposure of that area of the roof.
• Contribute to the photo-oxidation (i.e. premature deterioration) of the roof membrane, flashings and coatings.
• Challenge the adhesives used to make field-fabricated single-ply laps, thus compromising the integrity of the roof system.

It’s important to note that the care and maintenance language of most warranties clearly describes how a building owner is required to “maintain positive drainage,” or not allow water to pond and sit on a roof for 48 hours under dry conditions.

Aside from keeping a warranty valid, maintaining positive drainage is a sound maintenance practice that should not be taken for granted.

In short, excessive ponding can attract insects, mold or vegetation; cause structural damage to the building up to and including a roof collapse; and, in many cases, void a warranty.

First do a self-inspection that includes checking for obvious signs of clogged drains caused by tree branches or debris that can be easily removed. If that doesn’t solve the problem, contact a qualified roofing technician who can quickly diagnose the problem and efficiently repair it before it grows into a bigger, more costly issue.