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How To Tell When a Roof Needs Some Love

Bill Morris in Bricks & Bucks on March 20, 2019

New York City

Roof Q&A
March 20, 2019

Co-op and condo boards usually turn to their professionals when faced with a major repair to the building. Architects, engineers, plumbers, roofing contractors and other experts can be invaluable when it comes to estimating a building system’s life expectancy, finding the source of a problem, and complying with laws governing the maintenance of the building’s envelope and mechanical systems. But it doesn’t hurt for co-op and condo boards to know how to spot signs of trouble that can indicate looming problems. Dan Allen, a partner at CTA Architects, offers boards a primer on what they need to know when they see three specific conditions on a roof. 

Picture #1. Is that a koi pond on the roof? 

Dan Allen: I don’t see any koi in there. It’s just a drain that’s been neglected for a long time, long enough to grow all that algae around it. And that’s just standing water, so that’s not good for the roof. Eventually that water is going to find its way somewhere, and it may find its way through a slightly open seam and cause a real problem down the road. 

How do you fix it? 

DA: Unclog the drain by sending a snake down it, just like you do with plumbing. Or it might just be a surface clog, leaves and stuff that collect on the screen, if there is one. 

Picture #2. That looks like Lake Superior on this roof. Is that the result of a clogged drain like we saw in the first picture? 

DA: It's probably that plus the fact that the roof has inadequate pitch. For a flat roof to work, it’s got to be like a movie theater’s aisles – it’s got to be sloped enough to send the water toward a drain. This water has clearly been ponding for a long time because there's a nice accumulation of growth, a stable ecosystem of hay that's growing in the distance there. Proper pitching is a quarter of an inch per foot. 

So if there's if there's a hayfield on your roof, that’s a sign your roof probably needs some attention? 

DA: Absolutely. 

Picture #3. That looks like some sort of geyser. 

DA: That’s a duct that has been badly waterproofed. It’s an HVAC duct that’s been wrapped in what used to be called black-and-fabric, or mastic-and-mesh. Clearly the waterproofing isn’t working. Water has gotten in between the waterproofing membrane and the the metal of the duct. It’s easy to see. Stepping on it squeezes water out and forms a beautiful little Trevi Fountain, if you will. It’s very pretty, but that's not a good thing. If water gets into the duct, all sorts of bad things can happen in terms of breathable air. You don’t want water sitting in anything. 

So if you step on the ductwork on your roof and it squirts water, what should you do? 

DA: Well, you might want to redo the waterproofing. You might want to strip that stuff off and make sure the duct is intact. The duct may itself be waterproof, so this waterproofing may not have even been necessary. 

Any general advice for boards when they see unusual conditions on their roof? 

DA: No roof is maintenance-free. It’s important that the roof is easily accessible so you can get up there and check conditions regularly. Go up and check on your roof as often as you can, and cut off problems before they start. And when you replace a roof, hire professionals.

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