Rubber roofing (EPDM) is not the best system for flat roofs, but in some instances, it just does not work right off the bet, and when it leaks, repairing such a roof is not even an option. In late July of 2009 we began work on one such roof in Roxbury, MA – a neighborhood of Boston, located 15 minutes from downtown.

The roof was installed by an unqualified roofing contractor who apperanly never installed a rubber roof before, nor did he care about quality at all, which you can judge for yourself from the photographs of the roof that we’ve provided. As you will be able to see, this particular roof, though small, required a lot of detail work, which was the defining factor of whether this roof would leak or not. The roofer that installed the EPDM rubber on this roof, completely skipped the flashing part, choosing to instead caulk the corners with rubber lap sealants, and in some cases used the sealant to adhere membrane seams. As a result, most seams – even those that were glued together with rubber glue, partially or completely came apart.

In addition to the careless installation practice used by the contractor, the homeowner, Jim, was very concerned about insulation screws being loose under the roof and in some places penetrating it, creating more leaks. Despite all the corner cutting and improper installation, Jim had one advantage that kept his house more or less watertight, and without major roof leaks. The roof was built with a slight slope, which diverted all the water toward the wall drain, while parapet walls kept the water from spilling over the roof edges.

Just as a side note, this house used to be a part of a larger building, which was partially demolished at some point in time. Its current back wall used to be a separation firewall between different sections of the building. You can easily figure this out by looking at the brick on the front and back of the house. This brings up a mystery which I cannot solve: the through-wall drain is located in the back of the house, where the old separation wall is now. Therefore, back when the house was bigger, all the water would flow to the adjacent section of the roof. Still it had to drain somewhere, otherwise the house would be completely flooded, and the roof could have actually collapsed under all that weight. I suppose there were through-roof drains, which were buried / removed during one of the re-roofs and a through-wall drain was created when the rear part of the building was removed. I will come back to this topic later on, when I’ll discuss the parapet walls on this house. Continue reading →