Basement Waterproofing in Thornhill
Thornhill foundations were damp proofed rather than waterproofed, and thirty years on that coating has done everything it was ever going to do.
Basement Waterproofing in Thornhill, what we fix.
Basement leaks
Below-grade waterproofing
Sump pump installation
Balcony leaks
Terrace leaks
Underground parking waterproofing
Why our waterproofing actually holds.
Diagnose first
System-matched materials
Written warranties
Full documentation
Interior & exterior
Parking structure expertise
Diagnose first
We identify the actual entry point and failure mode before recommending a waterproofing system. The right system depends on the diagnosis.
System-matched materials
We specify and install waterproofing systems appropriate to the failure mode, not a one-size coating over everything.
Written warranties
Our waterproofing warranties are written, clearly explained before work begins, and transferable to future property owners.
Full documentation
Written inspection reports and completion documentation suitable for insurance, lenders, and reserve fund files.
Interior & exterior
We explain interior and exterior waterproofing options honestly, with the trade-offs, and recommend what's appropriate for your situation.
Parking structure expertise
Parking deck waterproofing, joint systems, and traffic membranes, commercial-grade capability applied to residential and commercial buildings.
“The right waterproofing system depends on what's actually failing. We find that out first.”
“The right waterproofing system depends on what's actually failing. We find that out first.”
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.
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.
Basement Waterproofing questions for Thornhill.
Interior systems run $100 to $250 per linear foot and exterior excavation with membrane runs $250 to $450 per linear foot. A single crack injection starts around $400. Most properties do not need the full perimeter treated, and the written quote covers only the sections the diagnosis supports.
They solve different problems. Exterior work stops water at the wall and relieves the pressure driving it, which is the more complete answer where groundwater is the cause, though it means excavation. Interior systems manage water that has already entered, at lower cost and much less disruption to landscaping. We tell you which failure mode you actually have.
Interior crack injection is usually a few hours and an interior perimeter system one to two days. Exterior excavation on a residential foundation runs three to five days depending on access and what the dig encounters. We give you the realistic range before starting rather than partway through.
Yes. Traffic bearing membranes, expansion joint systems, and crack injection across the condo and commercial stock around Commerce Valley and Highway 7. Reports are formatted for reserve fund studies, since on a condo the work has to be justified to a board before it can be approved.
Yes, written and specific to the system installed, handed over before work begins rather than afterwards. Terms differ between a crack injection, an interior perimeter system, and exterior work, so we go through what is actually covered instead of leaving you to find the limits when you need them.
Foundation cracks that have opened as backfill settled, window wells without functioning drains, and grading that has shifted toward the house over three decades so that surface water now arrives at the wall. The last two are cheap to fix and are checked before anybody talks about a system.
Basement waterproofing in Thornhill is largely a story about a decision made at construction. The foundations poured through the 1980s and 90s received a sprayed bituminous coating that resists soil moisture and was adequate for that. It was never specified to resist water under hydrostatic pressure, which on slow draining York Region ground is eventually what it meets.
The consequence is that whole streets arrive at the same point together, thirty years after everybody moved in. Each owner assumes their house has a unique defect. Usually it does not, and the useful question is not what went wrong but which of the cheap explanations has been ruled out before anybody proposes a system.
Check the Cheap Explanations First
Before proposing a system we rule out two things that cost very little to correct. Window wells without functioning drains fill during heavy rain and hold standing water against a below grade window never designed to be submerged. Grading that has settled toward the house over thirty years delivers roof and surface water straight to the foundation it was meant to carry away from.
Both are common on housing of this age and both are inexpensive. Finding one of them instead of a pressure problem changes the recommendation from several thousand dollars to an afternoon, which is why the inspection covers the outside of the building as carefully as the inside.
Damp Proofing Is Not Waterproofing
The distinction is the single most useful thing an owner of a 1980s or 90s Thornhill house can understand about their own building. Damp proofing is a coating that slows vapour and resists soil moisture. Waterproofing resists standing water under pressure. Builders applied the first and homeowners were told the second.
So a thirty year old basement developing its first leak is usually a predictable maintenance event rather than evidence of neglect or a construction defect. Knowing that changes how you should respond to the first quote that arrives, which is frequently for a full perimeter system the fault does not require.
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.