Commercial Roofing FAQs for Oakville Property Owners

How often should commercial roofs be inspected in Ontario?

We recommend biannual inspections for commercial roofs—once in spring to assess winter damage and once in fall to prepare for the freeze-thaw cycles ahead. Ontario winters are particularly harsh on commercial roofing systems, with temperature fluctuations causing expansion and contraction that can compromise membrane integrity, flashing, and seam adhesion.

Additional inspections after major weather events such as heavy snowfall, ice storms, or summer hailstorms help catch problems before they escalate into costly interior damage.

What are the most common flat roof drainage issues?

Ponding water is the leading drainage concern for flat and low-slope commercial roofs. When water remains on the roof surface for more than 48 hours after rainfall, it indicates inadequate slope or blocked drainage components.

Common drainage problems include:

• Clogged scuppers, drains, or downspouts from debris accumulation
• Compression of roof deck or insulation creating low spots
• Ice damming during winter months blocking natural drainage paths
• Undersized drainage systems for the roof area
• Deteriorated roof crickets or tapered insulation systems

Addressing drainage issues promptly prevents membrane deterioration, structural damage, and premature roof failure.

Do I need permits for commercial roofing work?

Most commercial roofing projects in Oakville require building permits, particularly for complete roof replacements, structural modifications, or significant repairs. Permit requirements ensure work meets current building codes and safety standards.

A qualified commercial roofing contractor will handle permit applications and coordinate necessary inspections. Minor maintenance work such as patching small leaks or replacing damaged flashing may not require permits, but it's always best to verify with your contractor and local building department before proceeding.

What's the difference between TPO, EPDM, and modified bitumen?

These are three popular commercial roofing membrane systems, each with distinct characteristics:

TPO (Thermoplastic Polyolefin)

A single-ply white membrane offering excellent reflectivity and energy efficiency. Seams are heat-welded for superior strength. Popular for its balance of performance and cost-effectiveness.

EPDM (Ethylene Propylene Diene Monomer)

A durable synthetic rubber membrane with proven longevity. Typically black, though white versions exist. Performs exceptionally well in temperature extremes and resists UV degradation.

Modified Bitumen

A multi-ply system using asphalt-based materials reinforced with modifiers for flexibility. Available in torch-applied, cold-applied, or self-adhered installations. Excellent for buildings with moderate foot traffic.

The right choice depends on your building's specific needs, budget, and existing roof structure.

When is repair better than replacement?

Strategic repairs extend roof life when damage is localized and the overall system remains sound. Repairs make sense for:

• Roofs less than halfway through their expected lifespan
• Isolated leaks from punctures, penetrations, or flashing failures
• Storm damage affecting specific sections
• Budget constraints requiring temporary solutions

Complete replacement becomes necessary when membrane degradation is widespread, structural issues exist, or repair costs approach 50% of replacement value. A thorough inspection reveals the most cost-effective long-term solution.

How does winter weather affect commercial roofs?

Ontario winters present multiple challenges for commercial roofing systems. Heavy snow loads stress structural components, while freeze-thaw cycles create expansion and contraction that can open seams and compromise adhesion. Ice damming occurs when heat escaping through inadequate insulation melts snow that refreezes at roof edges, creating water backup under the membrane.

Proper insulation, adequate ventilation where applicable, and ensuring drainage systems remain clear throughout winter months minimize weather-related damage. Professional snow removal may be necessary after significant accumulation to prevent structural overload.