Commercial roofing is a different world from residential. Flat and low-slope roofs require specialized materials and installation techniques that most residential roofers don't handle. Here's a breakdown of the four main commercial roofing systems and when each makes sense.
TPO (Thermoplastic Polyolefin)
TPO is the most popular commercial roofing membrane installed today. It's a single-ply, heat-welded membrane that's white or light-colored, reflecting UV and reducing cooling costs. Pros: energy efficient, relatively affordable, easy to repair. Cons: newer technology with less long-term track record than EPDM, quality varies by manufacturer. Lifespan: 15-25 years. Cost: $5-$8 per square foot installed.
EPDM (Ethylene Propylene Diene Monomer)
EPDM is the workhorse of commercial roofing — a synthetic rubber membrane that's been used for 50+ years. It's typically black, which absorbs heat (white versions are available). Pros: proven track record, flexible in cold weather, easy to repair, longest history of any single-ply system. Cons: black absorbs heat (higher cooling costs), seams are adhesive-bonded (not welded). Lifespan: 20-30 years. Cost: $4-$7 per square foot installed.
Modified Bitumen
Modified bitumen is a multi-layer system that evolved from built-up roofing (BUR). It uses asphalt-based sheets with polymer modifiers that improve flexibility and durability. Pros: excellent waterproofing, handles foot traffic well, familiar to most commercial roofers. Cons: requires torch application (fire risk during install) or cold-adhesive (slower), heavier than single-ply. Lifespan: 20-30 years. Cost: $5-$9 per square foot installed.
Standing Seam Metal
Metal roofing on commercial buildings uses standing seam panels — long vertical panels with raised interlocking seams. It's the premium option. Pros: longest lifespan, virtually maintenance-free, handles snow and ice well, excellent for buildings with steeper slopes. Cons: highest upfront cost, requires specialized installation, can be noisy in rain without insulation. Lifespan: 40-60 years. Cost: $8-$15 per square foot installed.
How to Choose
The right system depends on: building type (warehouse vs office vs retail), roof slope (flat vs low-slope vs steep), budget (upfront cost vs lifecycle cost), climate (Chicago's freeze-thaw is different from Greenville's heat and humidity), and foot traffic (rooftop HVAC units need a system that handles maintenance traffic).
MBE/WBE Commercial Roofing
Legacy Design Group installs all four systems and is certified MBE/WBE — qualifying for government contracts and corporate diversity requirements. We provide capability statements, insurance certificates, and prequalification packages for any commercial bid. Contact us for a commercial roofing assessment.
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