Spray polyurethane foam
Monolithic insulation and membrane in one, the recoat obligation that makes it a programme, and where it genuinely outperforms.
Commercial systems
On a low-slope roof, the seam is the system.
Membrane chemistry gets the marketing attention. Seam method, attachment, insulation, and the quality of the detail work decide whether the roof reaches its planning range.
30-second answer
Which commercial roofing system should we specify?
The one whose failure modes your building can tolerate. Chemical exposure, roof traffic, drainage, structural capacity, occupancy disruption, and the maintenance you will genuinely fund matter more than the membrane's name. Most systems here will perform on most buildings; the exceptions are specific and worth knowing.
Published guides
The systems, one page each.
Each goes deeper on one system than a head-to-head comparison can — including how it fails and what it demands of the crew installing it.
TPO
The most-installed low-slope membrane, and the one whose formulations have changed most — so early field record does not predict a current product.
EPDM
The longest continuous field record in single-ply. Its seam history is the clearest available lesson in why the seam is the system.
PVC
Chemical and grease resistance make it the correct choice near kitchen exhaust and certain industrial discharges — sometimes the only correct one.
Modified bitumen
Redundancy through plies: a breach in one does not immediately become a leak. APP against SBS, and the application methods including torch risk.
Built-up roofing (BUR)
The legacy benchmark. Why it persists, why it has declined, and the asbestos question on any pre-1990 commercial tear-off.
Coatings and restoration
The most oversold category in commercial roofing. The criteria that separate genuine restoration from burying a wet roof.
Coverage map
Systems and assemblies not yet written.
Listed so the gaps are visible rather than quietly absent. Nothing here is published.
Commercial metal
Structural standing seam and architectural metal at commercial scale, including thermal movement over long runs.
Vegetative and ballasted
Load, leak detection and repair access, and the maintenance obligation that outlives the enthusiasm.
Tapered insulation design
Designing positive drainage on a flat deck: crickets, saddles, and average R-value across a tapered field.
Rooftop equipment and penetrations
Curbs, pipe supports, walkway pads, and the HVAC service traffic that damages more membrane than weather does.
Wind uplift approvals
FM approvals and UL listings, attachment density, and why perimeter and corner zones carry different requirements from the field.
Solar-ready roofs
Sequencing solar against roof life, attachment against ballast, and the warranty interaction nobody resolves early enough.
Fall protection and access
Owner-side obligations: anchors, guardrails, access routes, and the contractor's own compliance.
Next step
Write a specification that yields comparable bids.
A system choice only becomes a project once the scope is defined tightly enough that three contractors price the same work.
Compare quotes properly