Flat roof repair in Southwestern Ontario

Leak repair, repairs, replacement and maintenance of flat roofs in 9 cities across southwestern Ontario, for homes and businesses.

Aerial view of large low-slope industrial roofs

Flat roofs in southwestern Ontario

From Waterloo Region to Windsor and Sarnia, southwestern Ontario has large industrial and logistics roofs, university and hospital buildings, and plenty of older homes with flat-roofed additions.

Snow loads rise as you move toward Lake Huron, where lake-effect snow builds up on roofs and drifts against parapets.

Roof design climate by city

CityGround snow load15-minute rainJanuary design temperature
Kitchener2 kPa28 mm-19 °C
Waterloo2 kPa28 mm-19 °C
Cambridge1.6 kPa25 mm-18 °C
Guelph1.9 kPa28 mm-19 °C
Brantford1.3 kPa23 mm-18 °C
London1.9 kPa28 mm-18 °C
Windsor0.8 kPa28 mm-16 °C
Sarnia1.1 kPa25 mm-16 °C
Woodstock1.9 kPa28 mm-19 °C

Source: Ontario Building Code, Supplementary Standard SB-1, Table 1.2. Values are design figures, not forecasts.

What this means for your roof

Snow loads are moderate here. Most damage comes from freeze–thaw cycles, ice at the drains in late winter and heavy summer rain.

Whatever the climate, most leaks start at details: seams, flashings, drains, vents and skylights. See roof problems for causes and fixes.

Starting prices

ItemStarting price
Small leak repair (patch, seam or puncture)from $350 per repair
Roof inspection with written photo report (house)from $250 per roof
House flat roof replacement (about 1,000 sq ft)from $8,000 per roof
Commercial roof replacementfrom $8 per sq ft

Starting prices in CAD before 13% HST, based on typical Ontario contractor rates (mostly Toronto and the GTA). The final price depends on roof size, access, the layers to remove, the membrane, drains and flashings, and is confirmed in your written quote.

Flat roof work in Southwestern Ontario

Do you work outside the cities listed for southwestern Ontario?

Often, yes. Tell us the town in the quote form. Smaller towns are quoted with travel time included.

Which roofs do you work on in southwestern Ontario?

Houses, townhouses, garages and additions, condo and apartment buildings, plazas, offices and warehouses. See property types.

Which flat roof material suits this climate?

EPDM, TPO, PVC and modified bitumen all perform in Ontario when installed and detailed well. See choosing a flat roof material.

Leak, damage or an old flat roof?

Send a few details and photos. We reply by email with next steps and a written quote.

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