The source, not just the stain.
We find the source others miss. Same-day leak tracing, diagnosis, and repair across the GTA.
Roof leak sources we diagnose and fix.
Every leak has a specific origin. We isolate it before we touch anything.
Active Leak Tracing
Flashing Failures
Flat Roof Repairs
Pipe Boots & Penetrations
Storm & Wind Damage
Drain & Ponding Water
Active Leak Tracing
Water path diagnosis
We trace from the interior stain back to the roof, not the other way around.
Flashing Failures
Most common source
Step flashing, counter flashing, valley metal. Flashing accounts for the majority of leaks we find.
Flat Roof Repairs
EPDM · TPO · Mod-Bit
Membrane splits, lap seam failures, blistering, and ponding water, every flat roofing system in the GTA.
Pipe Boots & Penetrations
Vents, stacks, HVAC
Rubber boots crack. HVAC curb flashing fails. Small repairs with large consequences if ignored.
Storm & Wind Damage
Post-event assessment
Lifted shingles, displaced flashings, and debris impact. We assess and document for insurance claims.
Drain & Ponding Water
Flat roof drainage
Blocked drains and low spots on flat roofs accelerate membrane failure. We clear, re-slope, and repair.
Water coming through a ceiling? We answer at 2am.
Why Blue Knight finds it when others don't.
25+ years on GTA roofs
Written diagnostic report
2hr response available
Commercial & residential
No exploratory repairs
25+ years on GTA roofs
We've seen every failure mode. We know where to look.
Written diagnostic report
Every repair includes photos and a written report you can hand to your insurer or property manager.
2hr response available
Roofs don't leak on schedule. We answer the phone and we show up.
Commercial & residential
From a detached home to a 50,000 sq ft warehouse, every roofing system in the GTA.
No exploratory repairs
We find the source before we start cutting. You don't pay for trial-and-error.
“Most roofers fix what they can see. We fix what caused it.”
“Most roofers fix what they can see. We fix what caused it.”
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.
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.
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.
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.
Featured Projects.
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.
Leak repair questions.
Same-day in most cases. For active leaks with water coming through, we treat it as an emergency and prioritize dispatch.
In almost all cases, yes. We've been doing this for 25 years, we know where leaks hide. Occasional exceptions: intermittent leaks that only appear in specific rain conditions.
Location of the leak source, photos, the failure mode (what failed and why), what was repaired, and materials used. Suitable for insurance carriers and property managers.
Depends on the cause. Storm damage, sudden events, and certain sudden failures are typically covered. Gradual wear is usually not. We document the damage thoroughly to give you the best chance with your insurer.
Most localized repairs are complete in half a day. Complex failures involving deck damage or multiple penetrations may take a full day.
What GTA Homeowners Ask About Roof Leaks.
The questions people search most, answered honestly by 25-year GTA roofers.
Most residential roof leak repairs in the GTA range from $350 to $2,000. Simple flashing fixes or a cracked vent boot run $350-$700. Larger failures involving deck damage, multiple penetrations, or flat roof membrane work can reach $1,500-$2,000+. We provide a written estimate before touching anything.
Insurance covers leaks from sudden, covered events, storm damage, hail, wind, or a fallen tree. Gradual wear and deferred maintenance are typically excluded. We document all damage in writing with photos, which gives you the strongest possible case with your insurer.
A repair is almost always cheaper in the short term ($350-$2,000 vs. $9,000-$22,000 for a full replacement). We recommend repair when the leak is isolated, the surrounding roof is structurally sound, and the roof has 8+ years of life left. If the membrane or shingles have failed broadly, replacement is the better long-term value.
Most localized repairs are done in half a day, 2 to 4 hours on site. Complex cases involving multiple penetrations, deck rot, or a difficult diagnosis may take a full day. We test the repair before leaving, so you know it is sealed before we pack up.
- How much does roof leak repair cost in Toronto?
- Most residential roof leak repairs in the GTA range from $350 to $2,000. Simple flashing fixes or a cracked vent boot run $350-$700. Larger failures involving deck damage, multiple penetrations, or flat roof membrane work can reach $1,500-$2,000+. We provide a written estimate before touching anything.
- Does home insurance cover roof leak repair in Ontario?
- Insurance covers leaks from sudden, covered events, storm damage, hail, wind, or a fallen tree. Gradual wear and deferred maintenance are typically excluded. We document all damage in writing with photos, which gives you the strongest possible case with your insurer.
- Is it cheaper to repair or replace a leaking roof?
- A repair is almost always cheaper in the short term ($350-$2,000 vs. $9,000-$22,000 for a full replacement). We recommend repair when the leak is isolated, the surrounding roof is structurally sound, and the roof has 8+ years of life left. If the membrane or shingles have failed broadly, replacement is the better long-term value.
- How long does a roof leak repair take?
- Most localized repairs are done in half a day, 2 to 4 hours on site. Complex cases involving multiple penetrations, deck rot, or a difficult diagnosis may take a full day. We test the repair before leaving, so you know it is sealed before we pack up.
- What should I do immediately when I discover a roof leak?
- Limit interior damage first: put a bucket under the drip, move furniture and valuables, and if water is pooling in a ceiling bubble, carefully poke a small hole to drain it in a controlled spot. Then call us, same-day response is available for active leaks. Every hour of delay spreads water further into insulation and framing.
- How soon does a roof leak need to be fixed?
- Within 24-48 hours ideally. Toronto's weather is unforgiving, a small leak in October becomes major water damage by December. What costs $500 to fix today can become a $5,000+ claim after a few weeks of water infiltrating insulation, drywall, and structural wood.
- Can I temporarily stop a roof leak myself until the roofer arrives?
- A tarp is the most effective DIY emergency measure, extend it at least 4 feet beyond the leak source in all directions and secure it with boards or sandbags. Roofing sealant tape can help on obvious surface cracks. Avoid going on a wet or steep roof without proper safety equipment. Call us first, we can often be there the same day.
- How do you find a roof leak?
- We trace from the interior stain backward to the roof surface, not the other way around. Water travels along rafters and decking before it drips, so the visible stain is rarely directly below the entry point. We use moisture meters to pinpoint wet zones and systematic visual inspection of the most common failure points: flashings, pipe boots, valleys, and seams.
- What are the early warning signs of a roof leak?
- Water stains or dark spots on ceilings or walls, especially near chimneys, skylights, vents, or exterior walls, are the first indicator. Peeling paint, soft drywall, or a musty smell in the attic follow. Don't wait for the ceiling to sag. Annual spring inspections catch leaks before they become emergencies.
- What causes most roof leaks in Toronto?
- Failed or corroded flashing is the single biggest culprit, chimney flashing, step flashing along dormers, and valley metal account for the majority of leaks we find. Cracked pipe boots, lifted shingles after wind events, and clogged or failed flat-roof drains are close behind. Toronto's freeze-thaw cycles stress every vulnerable point on a roof every single winter.
- Can I fix a roof leak myself, or do I need a professional?
- DIY works only if the damage is obvious, accessible, and isolated, a single cracked vent boot you can see and safely reach. The problem is that most leaks fail DIY attempts because homeowners patch the interior symptom rather than the actual roof-surface entry point, which is typically 10-20 feet away. Improper patches also make professional diagnosis harder and can void material warranties.
- How is a flat roof leak repaired differently from a shingle roof?
- Flat roofs use continuous membrane systems. TPO, EPDM, or modified bitumen, rather than overlapping shingles. Leaks develop at seams, penetrations, parapet edges, or membrane blisters, not at individual tiles. Repairs involve membrane patching, heat-welding seams, or replacing failed sections. Never hire a shingle specialist for flat roof work, the techniques and materials are completely different.
- Can a flat roof leak be permanently sealed, or does it need full replacement?
- Small, isolated leaks, under roughly 20 sq. ft., can be permanently patched with compatible membrane material. When we find multiple failure points, widespread blistering, or a membrane that is 20+ years old, patch repairs become a losing game and full replacement is the better investment. We assess the entire membrane before recommending anything.
- Why do roof leaks happen more in winter in Toronto?
- Toronto's freeze-thaw cycles, swinging from -15°C to +5°C multiple times per season, repeatedly stress shingles, flashings, and sealants. Existing small vulnerabilities that hold all summer open up when water freezes and expands inside them. Winter also brings ice dams, which force meltwater backward under shingles in ways normal rain never reaches.
- What is an ice dam and how does it cause roof leaks?
- An ice dam forms when warm air in the attic melts snow on the roof surface. The meltwater runs to the cold eaves, refreezes, and builds up a wall of ice. More meltwater backs up behind that wall with nowhere to go except under the shingles and into the building. The fix is usually a combination of improved attic insulation, ventilation correction, and sealing the ice-and-water shield layer, not just removing the ice.
More ways Blue Knight can help.
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.