Roof Repair in Markham
Heritage rooflines in Unionville, first cycle shingle failures across Berczy and Cornell. Every Markham repair starts where the water actually gets in, not at the stain it leaves on a ceiling.
Roof Repair in Markham, 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 Markham.
A targeted repair on a Markham house is typically $350 to $2,000, with the access and the kind of failure deciding where in that range it lands. Replacing the whole roof on a standard subdivision home in Berczy or Cornell is usually $9,000 to $22,000, and a Unionville or Markham Village roof in slate, cedar, or original metal sits above that because matched material costs more and goes on more slowly. Either way the figure comes to you in writing, itemized, after we have diagnosed the problem.
It is common across York Region and it is not a defect specific to your house. Many Berczy roofs were shingled at production speed while whole phases were closing, and where the nails went in above the line or the sealant strip never bonded in that first summer, the shingles give out well short of their rated life. We lift a section, check the bond and the fastening, and tell you whether a targeted repair buys real years or whether the first cycle is over.
That is most of the skill on those buildings. If the original slate, cedar, or metal cannot be matched exactly, you hear that from us at the estimate stage, not halfway through the job. What usually works is borrowing sound material from a rear or side slope for the elevation facing the street, then fitting the nearest available substitute on the slope nobody sees.
Because ventilation was built to a modest standard through the subdivision era and then frequently made worse. Plenty of Markham attics have had loose fill insulation blown in during the last two decades, and on many of those jobs it was pushed right into the eaves without baffles, sealing off the soffit vents that feed the attic its air. With no intake the deck runs warm and damp all winter, and the shingles above it age years ahead of schedule.
Wherever the weather and the roof allow it, yes, because we test the repaired area before the crew packs up instead of leaving you to find out from a ceiling. The written report then records what failed, what we did about it, and dated photographs of both.
When the sheathing under the shingles has softened or rotted, or when a past reroof was laid straight over the old shingles and nobody checked the deck beneath them, which is something we look for on postwar houses in Milliken and German Mills. Any repair on top of that kind of assembly is temporary, because the fault sits in the structure rather than the surface. We photograph the deck so you can see the problem for yourself instead of taking our word for it.
Roof repair in Markham, Ontario divides by construction era. Across Berczy, Cornell, Cathedraltown, and Greensborough the typical failure is the shingle itself: builder grade product, nailed quickly while whole phases went up at once, that starts letting go at the sealant strip and along the nail line somewhere between year fifteen and year twenty. From the driveway a roof like that can look finished when a repair would buy it years, so we settle that question on the roof before anybody mentions replacement.
On heritage property in Unionville and Old Markham Village the roof surface is rarely the issue. These buildings leak at their intersections: chimney counter flashing set into old mortar, valley metal that has outlived the covering above it, and sidewalls where a later addition met an original roofline and was flashed quickly.
What Fails on Markham Roofs
The patterns are predictable once the era is known. On the subdivision streets the weak points are the shingle and whatever pierces it: sealant strips that stop holding, nail lines that open up, and rubber pipe boots that split in the sun at about the fifteen year mark. Postwar housing in Milliken and German Mills fails at the details, particularly chimney flashing and valley metal that was reused during an earlier reroof and is now decades older than the covering around it.
Heritage property fails at its intersections and almost never in the field. Knowing that in advance is why our diagnosis is quick and our repairs hold, because we check where these buildings actually fail rather than patching the nearest shingle to the stain.
Ventilation Is Usually the Real Story
When a Markham roof wears out early, the cause is more often in the attic than in the shingles themselves. Warm moist air reaching a cold deck condenses, the deck stays damp through the winter, fasteners work loose in softened sheathing, and the covering above ages years ahead of schedule.
So the repair quote on a house of this kind includes what we found in the attic. Sometimes the honest answer is that the roof needs forty dollars of baffles and clear soffit intake rather than the replacement somebody else quoted, and saying so is the difference between fixing the building and selling a roof.
Flat Roofs Along Highway 7 and in Buttonville
Not every Markham repair is a shingle job. The commercial and low rise buildings along Highway 7 and around Buttonville run on flat membrane roofs, and those leak at drains, seams, and rooftop penetrations far more often than across the open membrane. We repair them with material compatible with the membrane already in place and note the condition of the rest of the roof while we are up there, so the owner knows whether the next call will be another patch or a planned replacement.
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.