Many years ago one of my property manager clients asked me to bid on a townhouse complex they managed. The townhouses were two stories tall, with a one story garage in front. The garage roofs were leaking in many areas and they ponded water quite badly. I advised them that ideally there should be little or no ponding on a rooftop, as large puddles not only degrade the roofing membrane prematurely, but also turn small leaks into big leaks. This particular association did not have the necessary funds for reconfiguring the roofs with tapered insulation (as this can be quite expensive) or to lower the existing drains. The property manager asked me what the best roof would be under these circumstances and I unhesitatingly recommended a thermoplastic roof. Of all the roof systems we had installed over the years, thermoplastic (TPOP) and PVC roofs stood up to ponding water better than any other system.
We won the bidding process that fall and installed new thermoplastic roofs on all 15 garage roofs. Over the winter there were no reported leaks, so I felt confident I had permanently solved my client’s leaky garage roof problem. By the time spring rolled around however, we began to get leak calls from the manager. Mystified, I went to the complex to find out what was going on. The first roof I climbed up on, I found a small hole in the membrane, and then another and another. Same thing on the next roof, though here I found the culprit, a cigarette butt. Thermoplastic roofs can be a great roof system, but under very high heat and depending on the manufacturer or origin, they can melt, making an instant hole. And a cigarette thrown down after the last puff was still just hot enough to burn through the membrane. And then it dawned on me as I looked up at the second story bedroom windows overlooking the garage roofs. People were smoking cigarettes while sitting on the window sill, taking in the breeze and then flicking their butts down on the lower garage roof, creating holes. We were able to eventually rectify the problem by educating the tenants about the damage their actions were doing to the roof, thankfully.
It had never occurred to me that this would be a problem when we were bidding, but in retrospect (and ever since) this is always something I take into consideration when advising a client what the best roof is for their project. Will there be a lot of foot traffic on the building, or will people have easy access to it? If so, Thermoplastic may not be the way to go.
So, as clients always ask me, what is the best roof system? It depends on many factors that must be considered and weighed when choosing a system for your building. One system may perform great on one building and be a disaster on another. In the next post, I will describe the different roof systems available on today’s market, as well as their strengths, weaknesses, and most ideal applications.