Commercial Roof Types: An Overview
Roofing Doctor Knowledge Base
Commercial buildings in Massachusetts and Rhode Island typically have flat or low-slope roofs that require fundamentally different waterproofing systems than residential sloped roofs. This overview covers the primary commercial roofing systems, their characteristics, and how they perform in New England.
Single-Ply Membrane Systems
Single-ply systems are now the dominant commercial roofing technology, having largely displaced built-up roofing in new construction.
EPDM (Ethylene Propylene Diene Monomer)
A synthetic rubber membrane, typically black, with the longest track record of any modern flat roofing system.
- •Thickness: 45-mil or 60-mil (60-mil recommended for Massachusetts)
- •Seam method: Tape adhesive or liquid adhesive
- •Color: Standard black (white-coated available)
- •Lifespan: 20-30 years
TPO (Thermoplastic Polyolefin)
The fastest-growing commercial roofing membrane, available in white and light colors, with heat-welded seams.
- •Thickness: 45-mil, 60-mil, or 80-mil
- •Seam method: Hot-air heat welding
- •Color: White (standard), gray, tan
- •Lifespan: 20-30 years
PVC (Polyvinyl Chloride)
A premium single-ply thermoplastic membrane with excellent chemical resistance and the longest commercial track record among thermoplastic systems.
- •Thickness: 50-mil, 60-mil, or 80-mil
- •Seam method: Hot-air heat welding
- •Color: White (standard), gray, tan
- •Lifespan: 20-30+ years
Modified Bitumen Systems
Modified bitumen uses polymer-modified asphalt applied in multiple layers, similar in concept to traditional built-up roofing but with improved flexibility and performance.
APP-Modified Bitumen
Atactic polypropylene-modified bitumen, typically torch-applied. Produces a tough, durable multi-layer system.
SBS-Modified Bitumen
Styrene-butadiene-styrene-modified bitumen, more flexible than APP. Can be torch-applied, self-adhered, or cold-applied.
Built-Up Roofing (BUR)
Traditional built-up roofing uses alternating layers of roofing felt and hot-applied asphalt or cold adhesive, topped with aggregate (gravel) or cap sheet. Once the dominant commercial system, BUR has been largely displaced by single-ply membranes in new construction.
Coatings and Recovery Systems
For aging but structurally sound flat roofs, coatings and recovery systems can extend service life without full replacement:
Choosing the Right System
The right system depends on:
- •Budget and ownership timeline
- •Building use (chemical/grease exposure, climate control, foot traffic)
- •Existing roof condition and compatibility
- •Energy efficiency priorities
- •Contractor expertise available
Roofing Doctor has experience with all major commercial roofing systems and can recommend the right approach for Massachusetts and Rhode Island commercial properties.