Ponding water is defined as water that collects and remains on the roof for more than 48 hours. A roof that is flat with very little slope is especially susceptible to ponding water. Learn all about this phenomenon, why it’s bad for the health of your home, and what you can do about it.
How Ponding Water Harms the Roof
- Ponding water can stress the roof, causing deck deflection. This results in more ponding water that further compromises the roof’s structural integrity.
- Areas vulnerable to ponding water are also susceptible to buildup of dirt and debris. These contaminants damage the roof surface membrane.
- When water remains for a prolonged period, it causes the growth of mold, mildew, moss, and algae. The growth of vegetation can also clog drains, thus causing further ponding.
- In the winter, ponding water can lead to ice dams. The formation and movement of ice “scrubs” the roof surface, causing damage.
- Ponding results in moisture buildup under the roof membrane. This drastically reduces insulation and thermal efficiency.
The Solution for Ponding Water on Your Roof
If you detect ponding water, then immediately bring in an inspector to ensure the roof is properly constructed. A roof should never be completely flat and have a minimum of ¼-inch of slope for every foot of roofing. A roof inspector can determine a solution; in most cases, it doesn’t require the entire roof structure to be taken apart and reassembled. Common and affordable fixes include the installation of a tapered insulation. Ponding may also simply be due to the blockage of gutters and drain exits, which most inspectors can easily clear.
Contact Allied Construction if water is collecting on your roof. Our roof and deck builders also provide roofing tips on how to detect and fix common roofing problems. Don’t let ponding water create unnecessary and unpreventable damage.
Edited by Justin Vorhees
Expert Roofing Inspections, Replacement, and Re-Roofing
Quality roofing, decking and fencing services in Bellevue, Bothell,
Kenmore, Kirkland, Lynnwood, Sammamish, Snohomish & Woodinville