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Roof replacements aren't always straightforward jobs.
AUTHORAnita Konfederak, Vice President of Merritt Engineering Consultants
PAGE #pp. 36-37
Inclement weather, noise, and existing defects are just a few problems that can befall a roof replacement, best to start in the Spring, find problems early and inspect often.
A roof replacement is a straightforward job, isn’t it? Not always. We had a $1.1 million project where multiple roofs were to be replaced with an excellent liquid-membrane roofing system which is sensitive to any trapped moisture beneath it. The owner was insisting on starting the roof work in the fall, something we don’t recommend due to inclement weather.
Complicating the project further were commercial and medical spaces below the roofs, where the occupants were very sensitive to noise and vibration, so the contractor was limited as to where and when he could work each day. This was anticipated to some extent, but this late in the year the contractor could not be as accommodating. And then the contractor ran into some problems.
What kind of problems? Moisture problems. After the contractor removed the roofing, moisture was noted on the roof deck, but the workmen continued installing the new roofing in order to meet an unreasonable schedule. When you find moisture, you’re supposed to dry it out before installing a new roof membrane. If you are working in the summer, residual moisture on the roof deck will usually evaporate, and you can continue roofing. But in late fall, that won’t happen. When the temperatures are cold or there is precipitation, then dew, frost or even ice forms on the roof early in the morning. A contractor has to be very diligent in addressing that moisture before laying down the new roofing membrane or insulation.
How did work scheduling complicate things? Due to the weather and noise complaints, the contractor never had three to four straight days to work. His tight schedule could not accommodate these setbacks, so the foreman began to rush his workmen to accommodate the client’s unreasonable schedule, and they did not pay as much attention as they should have to the condition of the roof substrate.
Is it common that a contractor’s work is limited in terms of hours or days? It is common to an extent. In New York City, contractors must be prepared for interruptions. High-end retail tenants, neighboring buildings such as schools, hospitals and theaters often file complaints if they are not properly notified of noisy work. Planning a roofing project is complicated because you are always working around weather. Good project management and supervision are key to pulling off a roof replacement project without a problem.
Back to this contractor. What happened? After a few weeks of work, we noticed some small blisters on one of the roofs. We cut the blisters open and detected moisture. Unfortunately, this happened at another roof level as well. Was it workmanship, or was the moisture caused by leaks from surrounding parapet walls, as the contractor initially claimed? An extensive investigation ensued to determine the cause.
What was your role in figuring out this problem? Our initial role is always to find problems when we do our weekly inspections. On this project we were able to catch this problem early and identify the days when work was rushed. Then our role was to prove exactly what caused the roof blisters. Through probes and water tests, we were able to eliminate surrounding wall conditions as a problem and pinpoint the workmanship as the cause. Fortunately the contractor was willing to pay for the testing if he was found at fault. Negotiating with a contractor to prove him wrong is not easy.
Then what? The contractor was willing to take responsibility for his work and ultimately ended up completely replacing two out of eight of the roofs he installed, at his cost. But the project took an additional six months to complete because it had to be put on hold over the winter in order to to resume in better weather in the spring.
What lessons can a co-op or condo board draw from this project? Co-op and condo boards should plan to start roofing projects early in the year, preferably late spring. They should retain a professional to inspect the roof work while it is in progress to make sure it is being done per the specifications and drawings. Engineers typically visit the site once or twice a week for a few hours. Resident managers or supers are a huge help when they check on the work as well and report any inconsistencies, such as workmen working in too low temperatures or while it is raining.
A roof replacement is a very costly improvement that has to last for 20 to 30 years. It pays to spend the money up front to specify the correct product and to have an engineer monitor the work.