Roof Repair in Oshawa
Roof repair in Oshawa begins with a proper roof leak diagnosis: we follow the water from the ceiling back to where it enters, then fix that point, whether it is a chimney on a 1940s house in Central Oshawa or a seam on a flat commercial roof.
Roof Repair in Oshawa, what we fix.
Roof leak repairs
Emergency tarping
Storm damage repair
Shingle repairs & replacement
Metal roofing
Flat roof repairs (EPDM, TPO, Mod-Bit)
Why Blue Knight finds it when others don't.
We trace first
Written reports
25+ years experience
No upsells
60-min emergency
Permanent repairs
We trace first
Every job starts with a full trace from interior stain back to the roof. We find the source before touching anything.
Written reports
You receive a written diagnostic report with photos, suitable for insurance, lenders, and property management files.
25+ years experience
Two and a half decades on GTA roofs means we've seen every failure mode across every building type in the region.
No upsells
We don't sell replacements when repairs are appropriate. Our invoice reflects what the building actually needs.
60-min emergency
Active leaks get same-day priority dispatch, around the clock, including nights and weekends.
Permanent repairs
We use manufacturer-matched materials and test the repair before we leave. No waiting for the next rain.
“We trace the leak from the stain back to the source. That's how leaks get fixed permanently.”
“We trace the leak from the stain back to the source. That's how leaks get fixed permanently.”
Rated 5 out of 5Blue Knight was, by far, the best. Responsive, ethical, totally professional — and their crew went above and beyond at no extra charge.
Rated 5 out of 5They installed a full new roof in one day. The crew worked around the house without us hardly knowing they were there.
Rated 5 out of 5I emailed at 4 a.m. and spoke with someone that same day. Estimate and completed work all within one day. Pricing was fair, work was excellent.
Blue Knight was, by far, the best. Responsive, ethical, totally professional — and their crew went above and beyond at no extra charge.
They installed a full new roof in one day. The crew worked around the house without us hardly knowing they were there.
I emailed at 4 a.m. and spoke with someone that same day. Estimate and completed work all within one day. Pricing was fair, work was excellent.
Luciano did not try to sell me a new roof. Appreciated the honesty — he showed up when he said he would.
We had a leak diagnosed by two other contractors who could not find the source. Blue Knight found it on the first visit and fixed it the same week.
Flat roof replacement on a commercial unit. Clean, fast, no surprises on the invoice. The crew left the site cleaner than they found it.
Called after a storm damaged our roof. Someone was on site within hours, tarped everything, and had us fully repaired before the next rain.
Had a slow basement leak for years. Every other company just caulked it. Blue Knight found the actual source and did a proper waterproofing job. No issues since.
Our neighbours recommended them for a valley repair. Small job, but they treated it like it mattered — showed up on time, matched the shingles perfectly, and charged exactly what they quoted.
Our Work.
Rooftops across the GTA.
From downtown Toronto to the 905 and beyond, one crew, one warranty, twenty-five years of GTA rooflines.
Service availability may vary. Call (647) 383-8664 to confirm coverage for your area.
Rooftops across the GTA.
From downtown Toronto to the 905 and beyond, one crew, one warranty, twenty-five years of GTA rooflines.
Service availability may vary. Call (647) 383-8664 to confirm coverage for your area.
Roof Repair questions for Oshawa.
When water is getting in, we treat it as same-day work: a crew comes out, finds the entry point and makes it watertight before leaving. Repairs that are not yet leaking are booked in the normal way, typically within 2 to 5 business days.
We start at the stain, work up into the attic looking for wet sheathing and marks along the rafters, then go onto the roof above that area. On older Oshawa houses with board sheathing, water can run along the gaps between boards before it drops, so the true entry point is often well upslope of the ceiling damage.
Many of these chimneys stopped serving a furnace when the heating was converted, and an unused chimney stays cold and damp, so its mortar crumbles and the flashing set into it works loose. We rebuild the joints and the flashing together, and where the chimney no longer serves any purpose we may recommend taking it down below the roofline and decking over the opening, which ends the problem for good.
Yes, including modified bitumen, EPDM and TPO membranes, and the drains, scuppers, parapet flashing and rooftop unit curbs where flat-roof leaks usually begin. Older industrial roofs in the south end sometimes carry several layers over wet insulation, and a moisture check tells us whether a repair will hold or the section needs replacing.
Usually, yes, but a repair through two layers is harder to make watertight, since fasteners have to pass through both and the lower layer may be brittle. We check the deck underneath where we can reach it, and if the second layer is hiding soft sheathing we will tell you a patch will not last.
Every estimate is written and follows an on-site look, because a phone quote on a house that has been reroofed three times would only be a guess. It sets out the scope, names the materials and includes the photographs behind the recommendation.
Yes, from converted older houses in the centre of the city to student rentals in the north end near the university and college. Landlords and property managers get the same written report and dated photos, which helps with tenant communication and any insurance claim.
Much of Oshawa's housing went up between the 1920s and the 1960s as the auto plants grew, and many of those houses are now on their third or fourth roof. That history shows as soon as we open one up. We find board sheathing patched with plywood, two layers of shingles where a reroof went over the old one, brick chimneys that stopped venting a furnace long ago, and flashing that has been sealed over rather than replaced. Leaks on these houses rarely come from the shingles alone, because the detail work around them is usually older than the covering.
Further north, Samac, Pinecrest, Taunton and Windfields are later subdivisions with plywood or OSB decks and simpler rooflines, but they have their own weak points: vent boots that crack with age, valleys where shingles were cut short, and lower roofs that meet siding without proper step flashing. Commercial and industrial buildings along Simcoe Street, Taunton Road and the south end add flat membrane roofs to the mix. We repair all three, and the diagnosis always comes first, in writing and with photos.
Roof Repair on Oshawa's Older Workers' Housing
The 1920s to 1960s houses in Central Oshawa, O'Neill and the streets that grew up around the original car plants were built modestly: small footprints, simple gable or hip roofs, and board sheathing nailed over rafters that are often lighter than modern framing. Since then most have been reroofed several times, frequently by different contractors working to different standards. Before repairing one of these roofs we check whether the boards still hold nails, whether the rafters have sagged at the ridge, and whether old layers are adding weight the structure was never meant to carry.
That groundwork decides the repair. On sound decking, a flashing or shingle repair can last as long as the rest of the roof. On boards that have dried out, split or rotted at the eaves, a patch will pull loose in the next windstorm, and the honest recommendation is to replace the affected decking or plan a full reroof. We explain which applies, with photographs, before any work is booked.
Roof Leak Diagnosis on Oshawa Flat and Low-Slope Roofs
Flat and low-slope roofs are common in Oshawa, from rear kitchen additions and enclosed porches on older houses to the plazas and industrial buildings along Simcoe Street and in the south end. On older industrial roofs the usual trouble is standing water: decks that have deflected over the years, drains sitting higher than the surrounding membrane, and scuppers blocked with debris. Ponded water works at every weak seam until one gives. We map wet areas with moisture detection before cutting anything, so the repair addresses the real extent of the damage and does not seal soaked insulation under a new patch.
We also cover nearby cities.
Ready to schedule your estimate?
We come to you, assess the roof, and give you a written quote. You are not obliged to proceed. Most estimates completed same week.