Commercial Flat Roof Materials Compared

Commercial flat roofing covers a wider range of materials than domestic work, with system selection driven by roof size, accessibility, loading requirements, and budget. Here's a comparison of the main options.

Single Ply Membranes (TPO, PVC, EPDM)

Single ply systems are the dominant commercial roofing solution for large flat roofs. They're lightweight, available in large sheet widths, and can be mechanically fastened, bonded, or ballasted. TPO and PVC are heat-welded at seams for a secure joint. EPDM uses adhesive or tape joints. Typical lifespan: 25–30 years.

Modified Bitumen

Modified bitumen (often called torch-on felt) is a torch-applied system using APP or SBS-modified bitumen membranes. It's a well-proven system for commercial roofs, durable and resistant to foot traffic. Often used in 2–3 layer systems. Typical lifespan: 20–25 years.

GRP Fibreglass

GRP is less common on very large commercial roofs due to the labour required for large areas, but is excellent for smaller commercial buildings, canopies, and complex detailing. Seamless and highly durable. Lifespan: 25–30+ years.

Liquid Applied Membranes

Liquid applied systems (cold-applied polyurethane or PMMA) are excellent for complex roofs with many penetrations, details, or as part of a refurbishment over existing membranes. They're seamless and can be applied in multiple coats. Lifespan varies by system.

Which System is Right for Your Building?

For most commercial flat roofs, single-ply (particularly TPO) offers the best combination of performance, longevity, and value at scale. For smaller commercial buildings under 200m², GRP or EPDM may be more cost-effective. We survey and specify for each project individually.