The roof is one of the most important aspects of your home. If your roof fails you, it kicks off a domino effect of water, structural, and possession damage that makes your comfortable space uncomfortable, unattractive, and potentially dangerous if mold takes root. When it’s doing its job and keeping us dry, we tend to forget about it altogether; however, your roof, like every other part of your house, needs regular maintenance and occasional repair in-between the expensive and laborious process of replacing it. And while roof failures often seem to come out of nowhere, your roof will actually give you plenty of warning that there’s a problem. For example, if you have a flat roof, ponding is a warning sign you shouldn’t ignore.
What is roof ponding?
Ponding on your roof is essentially just water that collects in a low spot after a rainstorm. It’s a puddle that sits there for a while, eventually evaporating and leaving behind a coating of dirt. You might be tempted to think that ponding on your roof means your roof is working; after all, that water didn’t leak into your house.
The problem is twofold, though. One, if installed properly and in good shape, your flat roof shouldn’t result in ponding at all—the water should flow freely to your gutters or drains. And two, ponding resulting from minor problems with your roof’s slope or minor low spots that can appear over time can accelerate damage to your roof through a variety of problems:
Sun lensing focuses the damaging rays of the sun onto your roof and speeding up the deterioration of its surface.Algae and other growth can begin on the damp, dirty surface at the bottom of a ponding area, eating away at your roof’s surface.Freezing and thawing cycles of ponded water during the colder months will stress your roof unnecessarily.If you notice ponding on your roof, you should take action. It might not require replacing the roof or even a big repair project—but you shouldn’t ignore it. So what should you do if you see a puddle on your roof?
How to deal with roof ponding
First, inspect the area above and (if possible) below the ponding to confirm that there is no leak. Puddles that seem to vanish quickly might make you think there’s no real problem, but that could indicate a tiny breach in your roof that is allowing that water to seep down to the decking and beyond.
Next, check your gutters and drains for obstructions. It’s possible that the ponding is the result of blocked drainage not allowing the water to flow properly off the roof. If all you need to do is clear out your gutters, you’ve saved yourself a lot of trouble.
If it’s not a drainage problem and you’re not ready to consider replacing the roof, there are a few strategies you can try:
Build up. You can attempt to build up the ponding area by applying some roofing cement and additional layers of roofing material cut into circles of increasing size. The idea is to eliminate the low spot that’s collecting water. Fillers. An easier solution is to fill in the ponding area with a roof filling compound like Greenslope or Rapidproof. This is essentially a self-leveling waterproof layer on top of your existing roof surface. Crickets. A roof cricket is a wedge-shaped object installed on the roof surface that diverts water flow around an obstruction. Typically, crickets are installed next to chimneys so water doesn’t collect at the seam where the chimney meets the roof, but you can adhere one or more to your roof surface to divert water around a ponding spot. You can buy crickets or even make your own—the key is their shape and placement so they disrupt the water flow. One key thing to consider if you use a cricket is to re-inspect to ensure you’re not just re-directing the water to another low spot, which will now commence ponding.If you try these solutions and you still have ponding problems, you might need to consider replacing your roof sooner rather than later. And be grateful to the tiny lakes that form on your roof: They’re an early warning system letting you know it needs attention.
