Low Slope & Flat Roofing in San Diego

The cost of low slope and flat roofing depends on the system and the drainage work. TPO single-ply and modified bitumen rise with membrane thickness, ply count and warranty term, and tapered insulation to correct ponding adds cost where it is needed. Repairs to an existing flat roof are a smaller job that depends on the area. We price it after a site visit, and estimates are free.

A properly installed TPO roof lasts 20 to 25 years in San Diego, and modified bitumen 15 to 20. The variable that matters most is not the membrane, it is drainage: a roof that ponds water after every rain will fail years early no matter what is on it. If your existing roof holds standing water 48 hours after rain, correcting the slope is part of the real fix.

Because most flat roof leaks are at seams, flashings, drains and penetrations rather than in the open field of the membrane, and patching the visible wet spot does not address them. Water on a low slope roof also travels a long way from the entry point before it shows inside. We trace the actual entry point and fix the detail, rather than adding another patch on top of the last one.

Yes, and that transition is one of the most common leak points on San Diego homes. It has to be detailed so the pitched roof drains onto the membrane and over it, with the membrane run up under the pitched assembly rather than butted against it. Roofers who mostly do pitched work often get this junction wrong, and it leaks the first winter.

For most San Diego residential low slope roofs, TPO is the default: heat-welded seams create a continuous membrane with no adhesive to fail, and the reflective white surface cuts cooling load and helps with Title 24. Modified bitumen makes sense where you want redundant layers or the roof sees foot traffic. We recommend based on the roof, not on one product.