Commercial Roofing in Ajax

There’s no single “best” — it depends on your building type, roof slope, budget, and how the space is used. That said, for flat-roofed commercial buildings in Ajax and the GTA, the most reliable systems are:

• TPO — best for energy efficiency and newer builds
• EPDM — best for longevity and Ontario’s temperature extremes
• Modified Bitumen — best for high foot-traffic roofs or industrial properties
• Tar & Gravel (4-ply BUR) — proven performer for large industrial buildings

Metro Roofing assesses your specific property before recommending a system — what works on a retail plaza differs from what works on a warehouse or office building.

Built-up roofing (BUR) — also called tar and gravel or 4-ply hot tar — is widely considered the most durable commercial roofing system for impact resistance and longevity. Its multiple reinforced layers create exceptional protection against foot traffic, debris, and Ontario’s harsh winters. Metal roofing is the strongest option for sloped commercial roofs, with lifespans of 40–70 years when properly installed.

Commercial roofing systems fall into three main categories:

1. Single-ply membranes — TPO, EPDM, and PVC. Lightweight, fast to install, and the most common choice for modern flat roofs.
2. Built-up roofing (BUR) — multiple layers of bitumen and reinforcing fabric, topped with gravel. Traditional and extremely durable.
3. Modified bitumen — a modernized asphalt system, torch-applied or cold-applied, combining the durability of BUR with easier installation and maintenance.

Metro Roofing installs and repairs all three systems across Ajax, Pickering, Scarborough, and the GTA.

A standard commercial flat roof is built in layers, each serving a specific function:

1. Structural deck — the base (concrete, steel, or wood)
2. Vapour retarder — controls moisture from inside the building
3. Insulation — typically polyisocyanurate (polyiso) board for thermal performance
4. Cover board — protects insulation and provides a stable surface for the membrane
5. Waterproof membrane — TPO, EPDM, modified bitumen, or BUR — the primary weather barrier
6. Surfacing/ballast — gravel, coating, or granules depending on system type

A complete commercial roof assembly typically measures 3–7 inches thick depending on insulation requirements and local building code.

A standard commercial flat roof assembly is typically 3.5 to 7 inches thick, depending on the insulation value (R-value) required by the Ontario Building Code and the membrane system used. Insulation alone accounts for most of that depth — the waterproof membrane itself is usually just 45–90 mils thick. Buildings in Ontario’s climate require higher R-values than warmer regions, which means more insulation depth is common here.

The commercial roofing industry has shifted significantly in recent years. Key trends relevant to Ajax and GTA building owners include:

• Cool roofing — white TPO and reflective coatings that reduce heat absorption and lower cooling costs
• Green/living roofs — vegetative systems gaining traction on urban commercial builds for stormwater management and insulation
• Solar-ready roofing — membranes installed with solar panel mounting systems integrated from the start
• Fluid-applied coatings — sprayed-on restoration systems that extend existing roof life by 10–15 years without full tear-off
• Enhanced warranty programs — manufacturer-backed 20–30 year warranties tied to certified installation

Metro Roofing stays current on all of the above — ask us about energy-efficient options during your free estimate.