Flat and low-slope roofs on Florida homes, additions and small commercial buildings are usually covered with a single-ply membrane. TPO and EPDM are the two most common.
What TPO is
TPO is a white, reflective thermoplastic membrane whose seams are heat-welded. The light color reflects sunlight, which helps with cooling in Florida heat.
What EPDM is
EPDM is a synthetic rubber membrane, usually black, installed in large sheets with seams joined by tape or adhesive. It has a long track record on flat roofs.
Heat and reflectivity
TPO's reflective surface suits Florida's sun. EPDM absorbs more heat unless it is coated.
Seams and repairs
Welded TPO seams are strong when done correctly; EPDM seams depend on the adhesive and the installer. Either way, drainage and flashing details matter more than the membrane name.
Drainage is the real issue
Ponding water shortens the life of any flat roof. Slopes, drains and scuppers should be checked at inspection.
