Flat Roof Replacement on a Colonial Addition in Hatboro, PA — EPDM Membrane System

The rear addition of this Hatboro colonial had been covered with a modified bitumen flat roof since the addition was built in the late 1980s. By the time we were called in, the membrane had been patched three separate times in the prior decade, with chronic ponding water accumulating near the parapet wall on the northeast corner and active seepage into the addition’s ceiling that had produced two rounds of drywall repair without addressing the roof source.

The core problem was dual: the failing membrane and a flat roof with no drainage slope, which caused water to stand for days after any rainfall and accelerated the membrane’s deterioration. We removed the existing system down to structural decking, installed a tapered polyisocyanurate insulation board system that introduces a 1/4-inch-per-foot slope toward the interior drain, and completed the assembly with a fully-adhered 60-mil EPDM membrane with factory-welded seams and sealed penetrations at two HVAC curbs and the exhaust vent.

The EPDM system carries a 20-year material warranty and requires no maintenance beyond an annual visual inspection. The addition has been dry through two full Pennsylvania winters since completion.