Hello Tim,
I have a commercial building in New Jersey with about 2,000 sq.ft. of hot tar roofing, and six enlarged downspouts, with the top of each box cut out to allow overflow if the downspout gets plugged (frozen or otherwise blocked).
My roofer has put in a new roof two years ago, but I have frequent leaks which he blaims on plugged exit boxes. I have eliminated all nearby trees, etc., so no debris is really getting on to the roof. I am trying to get the final solution to my problem...any suggestions? Many thanks.
Norman
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Norman,
You need a second or third opinion. from some other roofers. I also feel you made a mistake going with hot tar. I would have sprung for rubber roofing. It costs more, but when a rubber roof is installed correctly, it can be leak-free for nearly 20 years or more!
I would also try to recreate the leak in fair weather. You know where the water enters the building, so go up on the roof near those areas with a garden hose and let water flow across the roof. Look for places where water puddles. Be aware that 90 percent of all roof leaks happen at flashings. Flashings are transitional roofing materials and connect roofs to things that stick up through or next to roofs. Your roofer made the flashings possibly by lapping up the felt paper and coating it with tar.
Tim Carter
www.askthebuilder.com
W3ATB