The mid-century-modern house that the TOH team is tackling in Brookline has a flat overhanging roof, an architectural element typical of the style, but one that can be prone to dry rot caused by standing water on the roof.
For the renovation, the homeowners and their architect chose a low-maintenance rubber roof. TOH general contractor Tom Silva and home builder Charlie Silva made sure the PVC roofing was installed properly at every step of the way—including a drip edge and PVC soffits and fascia—to minimize the chance of water ever causing a problem.
“The biggest obvious challenge from a waterproof point of view with that style of roof is the low pitch,” Tom explained. “With a traditional, steeply sloped roof, the pitch can be 6:12 or more, meaning the slope rises 6 inches for every 12 inches of run, which makes the water run off more effectively. At the Brookline house, we have a 1:12 pitch, just one inch of rise.” One upside of a flat roof is the fact that installing it doesn’t involve the usual dangling at risky angles.
For this installation, Tom and Charlie laid down ISO insulation board first, a lightweight, high R-value cellulose board with an isocyanurate foam core. Then they glued the PVC roofing material in place and installed a drip edge and snow guards.