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While potential roof leaks are a primary concern for just about anyone when a storm comes, heavy rains often bring with them a number of other secondary problems such as flooding. In the last few years, rains seem to be more sudden, faster and heavier than ever before, often exposing substantial drainage problems beyond the roof. Near our corporate headquarters in Phoenix, AZ (the desert, which is usually very dry… ), we’ve actually witnessed the creation of lakes in a matter of an hour right on our major freeways — literally, cars with water flooding into their windows.
While a roofer probably can’t prevent a flood on a freeway, our industry does carry extensive experience in drainage and the path of water, and several new roof products are available to assist with water retention and storm water management . More specifically, property owners and managers that often deal with drainage problems beyond their roof now have additional solutions beyond collection basins, drains, retention ponds and other common avenues. The answer to which may actually be right on their roof.
The options generally come in 2 flavors:
First, there are “green” or vegetative roofing systems, which we’ve talked a bit about in prior posts. These include roof systems with a major component that is plant-related. This is a layer of actual dirt / soil with various types of plants such as vegetable gardens or grass lawns.
The other new, yet less talked about option, includes actual roof systems intentionally designed and engineered to hold water. One such solution is Carlisle Syntec’s Ballasted Stormwater Retention roofing system. This option improves upon the time-proven ballasted roofing system by adding additional layers between the roof membrane and ballast. These additional layers are made of various materials that are specifically designed to retain moisture.
Photo Courtesy of Carlisle Syntec
Imagine a scenario that involves a heavy, one-inch rainfall. For a 10,000 square foot building, this means 6,200 gallons of water. Carlisle Syntec’s system would retain up to 67%, or 4,177 gallons, while only adding 3 lbs per square foot of roof area. This is a perfect solution for a property that otherwise doesn’t have an adequate drainage system or path for water after it runs off the roof.
While these roof systems aren’t quite as popular or seemingly “green” as the vegetative roof systems, they do offer a number of other benefits including:
Both options do require a well-built structure that is able to hold the additional weight. At any rate, many buildings, old and new, are perfect candidates. If you happen to have a property without adequate drainage or are interested in any of the other benefits, one of the above options may be a perfect solution.
