Shingles need slope to shed water, so flat and low-slope roofs — common on additions, porches, dormers and commercial buildings in New Jersey — use membrane systems instead. Here are the three main options.
TPO (thermoplastic)
A single-ply white membrane that's become the go-to for low-slope roofs. It's energy-efficient (the reflective surface cuts cooling costs), durable, and heat-welded at the seams for a watertight bond. Great value and lifespan (20–30 years).
EPDM (rubber)
A proven synthetic-rubber membrane, usually black, known for durability and flexibility in NJ's freeze-thaw climate. Long track record, easy to repair, typically 20–30 years.
Modified bitumen
An asphalt-based membrane in layers (a modern evolution of "tar and gravel"). Tough, good for roofs with foot traffic, and can be installed in multiple plies for redundancy.
Which is right for you?
- Want energy savings + modern performance: TPO.
- Want a proven, repairable rubber roof: EPDM.
- Roof sees foot traffic / want layered durability: modified bitumen.
Cost
Low-slope roofing typically runs about $7–$14 per square foot installed in NJ, depending on the membrane, insulation and access. The most important factor is the installer — flat-roof seams and flashing details are where cheap jobs fail.
Lightning installs flat and low-slope systems on New Jersey homes and buildings. Get a free estimate.