Greater Toronto Area
Flat roof repair in Oshawa
We repair, replace and maintain flat roofs in Oshawa: houses, garages and additions, condo and apartment buildings, plazas, offices and warehouses. Send photos and a few details for a written quote.
Flat roof services in Oshawa
Much of Oshawa's housing is older, and older houses often have flat roofs over rear additions, porches and garages. Typical signs are a stain on the kitchen ceiling, water at a skylight or a roof with several worn layers. 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.
Older cores and newer suburbs in Oshawa
Oshawa is a factory city. Robert McLaughlin moved his carriage works there in 1878, GM of Canada was created in 1918, and the population grew from about 4,000 to 16,000 during the 1920s. In 1951 GM moved its main plants to south Oshawa, and factories eventually covered several blocks. The Port of Oshawa still serves the auto and steel industries. Census data show about 59% of homes were built before 1981 and about 24% before 1961.
Downtown holds City Hall, the Robert McLaughlin Gallery, office buildings and Ontario Tech University, plus older brick storefronts, where flat roofs over rear sections are common. In neighbourhoods such as Donevan, Vanier, Lakeview and Eastdale you often find older housing and plazas, and the Oshawa Centre area adds large commercial roofs. Northglen, Windfields and Taunton are newer. The GM lands, industrial parks and logistics buildings have the large low-slope roofs typical of manufacturing cities, often with decades of patching behind them.
Oshawa 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 Oshawa has to handle.
- 1.4 kPaGround snow load (about 29 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
- -19 °CJanuary design temperature
- 3,860Heating degree-days per year
- 0.48 kPaHourly wind pressure, 1-in-50-year
That snow load is about 1.6 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.
Environment and Climate Change Canada climate normals (1991–2020) record about 102 cm of snowfall a year at the Oshawa WPCC station.
Source: Ontario Building Code, Supplementary Standard SB-1, Table 1.2
Homes and buildings in Oshawa
The age and type of buildings shape the flat roofs we see. These are the 2021 Census figures for Oshawa.
- 59%Homes built before 1981
- 21%Homes built since 2001
- 64%Detached and semi-detached houses
- 10%Row houses and townhouses
- 11%Apartments in buildings of 5+ storeys
- 36%Households that rent
About 59% of homes in Oshawa were built before 1981, more than in 25 of the 40 Ontario cities on this site. Older houses often have flat roofs over rear additions, kitchens and porches, sometimes with two or three layers of old roofing on top of each other. Replacing one usually starts with a full tear-off and a look at the wood deck underneath.
36% of households in Oshawa rent. Landlords and property managers can send photos and the tenant's description of the leak, and we reply with the scope and a quote by email. See apartment buildings.
Oshawa: facts for property owners
- Population of Oshawa: 175,383 (2021 Census). Source
- Oshawa is part of the Regional Municipality of Durham.
- City of Oshawa: replacement of roof shingle and non-structural roof repair do not require a building permit (houses). Source
Rules and programs change. Confirm current details with the municipality before you start work.
Starting prices in Oshawa
| Item | Starting price |
|---|---|
| Small leak repair (patch, seam or puncture) | from $350 per repair |
| Small flat roof replacement (garage, porch or addition) | from $4,000 per roof |
| House flat roof replacement (about 1,000 sq ft) | from $8,000 per roof |
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.
Roofs we work on in Oshawa
Nearby cities
Flat roofs in Oshawa: questions
How much does flat roof repair cost in Oshawa?
A small leak repair starts from $350 per repair and a new house flat roof starts from $8,000 per roof. Prices in Oshawa depend on access, layers to remove and the membrane. See pricing.
What causes most flat roof leaks in Oshawa?
Details more than the open membrane: seams, parapet and wall flashings, drains, vents and skylights. See flashing leaks and clogged drains.
Do I need a permit to replace a flat roof in Oshawa?
City of Oshawa: replacement of roof shingle and non-structural roof repair do not require a building permit (houses). That wording is about shingles, so ask how it applies to a flat roof membrane. Rules can change, so confirm with the building department before you start. See re-roofing permits in Ontario.
My Oshawa house is older. Can the flat roof go on over the old one?
Sometimes one new layer can go over one old layer, but on older houses we often find two or three layers already, wet insulation or soft deck boards. Then a full tear-off is the safer choice. See repair or replace.
Do you also work near Oshawa?
Yes, including Whitby, Ajax, Pickering and the rest of the GTA. See Greater Toronto Area.
Leak, damage or an old flat roof?
Send a few details and photos. We reply by email with next steps and a written quote.