4 Strategies to Remedy Ponding Water on a Low-Slope Roof
Water that remains on the roof after 48-72 hours can accelerate the aging of the roof membrane, shortening the roof’s life. It also causes dust and dirt to collect, seeds to germinate, algae to grow, and microbes to flourish. It’s a slip-and-fall walking-working surface hazard for individuals on the roof too.
Don’t just throw your hands up. There are several ways to remedy ponding water.
1. Improve Roof Slope
Slope impacts the roof’s ability to move water off the surface during rain and snowfall. The International Building Code (IBC) requires that membrane (i.e., built-up, modified bitumen, and single ply) have a minimum slope of 1/4 in. per foot, with coal tar-built up being an exception (minimum required slope for these roofs is 1/8 in per foot). When it’s time for reroofing, lightweight tapered concrete can be poured or tapered insulation installed if the deck doesn’t have an adequate slope.
2. Fix Problem Areas With Repairs or Roof Modifications
A depression in the roof provides an opportune place for water to collect. Deflection caused by a corroded deck, wet insulation, or heavy rooftop equipment may be to blame for large puddles. Consult your roofing contractor who can evaluate the source of the problem and whenever possible, prescribe repairs or modifications to keep water moving off the roof. For example, adding crickets may remedy low points, and saddles installed on the high side of curbs can keep water and snow from collecting there.
3. Improve Roof Drainage
The Intl. Plumbing Code (IPC) offers guidance for enclosed roofs (i.e., with parapet walls). For that type of roof, when it measures less than 10,000 square feet, IPC requires two (or more) roof drains. Roofs with parapet walls that are larger, should have a minimum of four roof drains. Your roofing contractor working with a qualified engineer, can calculate the necessary drainage requirements for your specific roof based on area weather data and the predicted quantities of how much water drains, pipes, gutters, and downspouts of varying sizes can move.
If your roof is experiencing regular ponding water, adding drains or sump pans, or lowering and enlarging gutters may help improve the flow of water from the roof. A careful evaluation from your roofing contractor can yield recommendations for the best corrective actions.
4. Perform Routine Roof Maintenance
When drainage is impeded, water ponding or pooling can occur on the roof and potentially compromise the waterproofing of flashings, pitch pockets, and the overall roof system, resulting in preventable leaks. The solution could be as simple as performing ongoing maintenance to ensure that drains and gutters are not clogged. A schedule of regular and routine maintenance will ensure that sticks, leaves, dirt (and other storm debris), as well as rags and food/beverage containers left by rooftop workers don’t impact the drainage.
Contact D. C. Taylor Co. today at 319.731.4118 or via email at [email protected] to investigate the cause of ponding water or perform general preventive maintenance on your roof(s).
Previous