Flat roof repair in Whitby

Flat roof services in Whitby

Whitby has a lot of newer housing, and on newer flat roofs leaks usually start at details rather than the whole membrane: a terrace door, a rooftop unit or a drain on a roof that is otherwise sound. We find where the water gets in, fix that spot and tell you how much life the rest of the roof has.

When a roof is past repair, we replace it with EPDM, TPO, PVC or modified bitumen, and fix the drainage so water does not sit on the new membrane. Owners and property managers also book inspections and maintenance visits.

Harbour town, steel mill and Brooklin: Whitby's roofs

Whitby began around its harbour. Grain was first shipped from there in 1833, the town became the seat of government for Ontario County in 1852, and a railway to Port Perry was built in the 1870s. Population then climbed from 2,732 in 1871 to 138,501 in 2021, with the biggest jumps in 1961 (up 102.1%) and 1991 (up 67.0%). About 70% of homes are single-detached, and census data show about 25% were built before 1981 and 39% in 2001 or later.

Downtown Whitby, centred on Dundas Street, has older brick commercial buildings and houses where flat roofs over rear additions and storefronts are common. The growth decades of the 1960s and 1990s left large subdivisions, plazas and schools of those eras. Brooklin and Ashburn in the north are separate communities from the urban south, and with 39% of homes built since 2001, newer membrane roofs on townhouse blocks and garages are part of the picture. In the south, employers such as a Gerdau Ameristeel steel mill, a Sobeys retail support centre and an LCBO warehouse occupy very large low-slope buildings. Trafalgar Castle, from 1859 to 1862, is a reminder that the town also has individual heritage buildings.

Whitby weather and your flat roof

Ontario's Building Code sets the climate values used to design roofs in each municipality. They show what a flat roof in Whitby has to handle. Figures are for southern Whitby. Brooklin, in the north, has a higher snow load.

• 1.2 kPaGround snow load (about 25 lb per sq ft)
• 0.4 kPaRain load added to snow (Sr)
• 23 mmRain in a 15-minute storm (design value)
• 86 mmRain in one day, 1-in-50-year storm
• -20 °CJanuary design temperature
• 3,820Heating degree-days per year
• 0.48 kPaHourly wind pressure, 1-in-50-year

That snow load is about 1.3 times the Toronto figure. Snow drifts against parapets, walls and rooftop units, and the weight sits on the roof for weeks. Drains that freeze shut leave meltwater nowhere to go.

Short summer storms can still drop 23 mm of rain in 15 minutes, so drains and scuppers have to be clear and sealed.

Source: Ontario Building Code, Supplementary Standard SB-1, Table 1.2

Homes and buildings in Whitby

The age and type of buildings shape the flat roofs we see. These are the 2021 Census figures for Whitby.

• 25%Homes built before 1981
• 39%Homes built since 2001
• 72%Detached and semi-detached houses
• 13%Row houses and townhouses
• 7%Apartments in buildings of 5+ storeys
• 18%Households that rent

39% of homes in Whitby were built since 2001, one of the higher shares among the cities we cover. Newer flat roofs rarely fail across the whole membrane; they leak at details first: flashings at rooftop units and terraces, drains and dried-out sealants. A maintenance visit catches those early.

13% of homes in Whitby are row houses or townhouses. Flat sections often run across several units, so a leak can start on a neighbour's part of the roof or at the joint between two units. See townhouses and row houses.

Source: Statistics Canada, 2021 Census Profile

Whitby: facts for property owners

• Population of Whitby: 138,501 (2021 Census). Source
• Whitby is part of the Regional Municipality of Durham.
• Flow Control Roof Drainage Declaration: Building permit submissions may require a 'Flow Control Roof Drainage Declaration Form' (rule on roof drainage design for engineered roofs). Source

Rules and programs change. Confirm current details with the municipality before you start work.

Starting prices in Whitby

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.

See all prices.