To Every Roof Job, There Is a Season

Habitat spoke with Anita Konfederak, vice president of Merritt Engineering, about one of the biggest challenges for co-op and condo boards.

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 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, dew, frost or even ice form 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 3 to 4 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 to the condition of the roof substrate. 

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 the 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. The owner had to pay for this additional forensic work, which was an unforeseen expense.

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?

Boards should plan to start roofing project 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 and supers are a huge help when they check on the work and report any inconsistencies, like 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 upfront to specify the correct product, and to have an engineer monitor the work.