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A flat commercial roof in Hamilton with membrane seams, a brick parapet wall and a roof drain

Hamilton Flat Roof Repair: Flat Roof Repair in Hamilton

Hamilton Flat Roof Repair finds and fixes flat roof leaks for homeowners, landlords and property managers across Hamilton. We repair EPDM, TPO, SBS torch-on and tar and gravel membranes, replace wet insulation, and rebuild drains, scuppers and parapet flashings. We are one of the few flat roofing companies in Hamilton that publishes what the work actually costs.

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Serving Hamilton and surrounding areas

We find the entry pointThe leak is rarely above the stain on your ceiling.
Core cut before quotingWe show you whether the insulation is wet.
Fixed written scopeMembrane, area and insulation, at a set price.
Repair or replace, statedA clear rule based on wet area, not on age.

Hamilton has an unusual concentration of flat roofs for a city this size, and most of them are older than the people living under them. The brick commercial blocks along Barton, King and James, the north end industrial stock, and the flat-roofed rear additions on half the century houses below the escarpment were all built with parapets and internal drains rather than eaves and gutters. That detail matters, because a flat roof with a parapet has nowhere to shed water except through a drain. When the drain blocks, the roof becomes a shallow pond with a wall around it.

Why Hamilton flat roofs leak

Rainwater standing on a flat roof membrane. Illustrative photograph.
Rainwater standing on a flat roof membrane. Illustrative photograph.

Three things account for most of what we are called to. Ponding. A flat roof is not actually flat. It is built with roughly 2 percent fall toward its drains or scuppers, and decks that settled, or that were framed level in the first place, hold water instead of shedding it. Water still standing 48 hours after rain counts as ponding, and it is not harmless weight: ponded water adds about 5.2 pounds per square foot for every inch of depth. Two inches across a small roof is several tonnes the deck was never designed to carry, and it sits exactly where the membrane is weakest. Freeze-thaw at the seam. Hamilton's winters cross the freezing point constantly rather than staying cold, so ponded water freezes and thaws repeatedly in the same spot. Every cycle works at the seam and the flashing. Movement at the edges. Parapets, curbs and drains are where two materials meet and move against each other. Almost no leak we find starts in the open field of the membrane. It starts at an edge.

The part of the roof you cannot see

The membrane is the cheap part. The insulation underneath it is what decides the bill. Once water gets through the membrane it does not stay put. It travels sideways between the membrane and the insulation, so the wet area is almost always far larger than the hole and rarely directly above the stain on the ceiling. Wet insulation does not dry out in place under a sealed membrane, it loses most of its R-value, and it stays a permanent water reservoir feeding the deck below. This is why we cut a test core before quoting anything. It is the only way to know whether you are buying a patch or a section, and any quote issued without one is a guess. It also tells us how many roofs are already up there. Older Hamilton buildings frequently carry two or three layers, and once a deck is loaded with that much accumulated roofing, another overlay is usually the wrong answer structurally as well as financially.

Residential flat roof repair services in Hamilton

A roof drain with its clamping ring, set into flat roof membrane. Illustrative photograph.
A roof drain with its clamping ring, set into flat roof membrane. Illustrative photograph.

EPDM Flat Roof Repair in Hamilton

EPDM is the black rubber membrane on most residential flat roofs here. It fails at the seams and at the flashings rather than in the field, and it is repaired with cleaned, primed seam tape rather than with caulk. Caulk on an EPDM seam is a two-month repair.

TPO Flat Roof Repair in Hamilton

TPO is the white or light grey membrane common on newer builds and additions. Its seams are hot-air welded, not taped, so a proper TPO repair needs a welder and a technician who can set the temperature and speed to the sheet. A welded seam is tested with a probe afterwards.

SBS Torch-On Flat Roof Repair in Hamilton

SBS modified bitumen is the two-ply torch-applied system found on a great many Hamilton flat roofs. Repairs rebuild both plies, base and cap, staggered so the laps do not stack. Torch work carries a fire watch, and it is not appropriate over every deck or near every wall assembly.

Tar and Gravel (BUR) Flat Roof Repair in Hamilton

Built-up roofing is the oldest system still in service here, layers of felt and bitumen under gravel ballast. Repairs mean sweeping back the gravel, cutting out the failed area and rebuilding to the same ply count. It is unglamorous and it works.

Flat Roof Leak Repair in Hamilton

The repair is the easy half. Finding the entry point is the job, and it is what separates a repair that holds from one that moves the stain to a different part of the ceiling.

Roof Drain, Scupper and Parapet Flashing Repair

Drains, scuppers and parapet flashings are where most Hamilton flat roofs actually fail. A drain that has lost its clamping ring, or a parapet cap that has opened at a joint, will leak regardless of how sound the membrane is.

Emergency Flat Roof Repair in Hamilton

We take emergency calls for active leaks, storm damage and blocked drains during heavy rain. We will stop the water first and quote the permanent repair afterwards.

Commercial flat roof repair in Hamilton

We repair and maintain flat roofs on commercial, industrial and multi-residential buildings across Hamilton. Commercial roofs fail differently from residential ones, because there is equipment on them and people walking around it.

Rooftop Unit and Curb Flashing Repair

Every rooftop unit sits on a curb, and every curb is a penetration through the membrane. Units that have been serviced repeatedly are usually surrounded by damaged membrane, because technicians work where they can stand.

Scheduled Inspection for Property Managers

Twice-yearly inspection in spring and autumn, with drains cleared, seams probed and a written condition report with photographs. On a portfolio of buildings this converts unpredictable emergency spend into a planned line item.

How to tell it's time

Call us if you recognise any of the following.

  • A stain on the ceiling, whether or not it is currently wet.
  • Water still standing on the roof more than two days after rain.
  • Blisters, ridges or bubbles in the membrane.
  • Seams that have lifted, curled or opened at the edge.
  • The surface feels soft or spongy underfoot in places.
  • Gravel washed away in patches, exposing the felt beneath.
  • A drain that is slow, or a scupper that is blocked.
  • Open joints or loose caps along the parapet.

How we find and fix a flat roof leak

Every job follows the same five steps.

  1. Interior review. We locate the stain relative to parapets, drains and curbs. The entry point is usually uphill of it, because water runs between the membrane and the insulation before it finds a way through the deck. Repairing directly above the stain is the most common wasted repair in this trade.
  2. Surface survey. We walk the roof, probe every seam and flashing, and mark soft areas.
  3. Core cut. We cut a test core through membrane and insulation to see whether the insulation is wet and how many layers sit on the deck.
  4. Written scope. You get the membrane, the area and the insulation to be replaced, at a fixed price.
  5. Repair and water test. We cut back to dry material, rebuild insulation, membrane and flashings, then flood-test drains.

Flat roof repair or replacement in Hamilton

Our rule is about wet area, not about age. We repair when the wet insulation is confined to roughly a quarter of the roof or less and the deck is sound. We replace when it is more than that, when there are already two or more layers up there, or when the deck itself has been compromised. A roof with three isolated leaks and dry insulation is a repair, even at twenty years old. A ten-year-old roof with half its insulation saturated is a replacement, because you would be paying to rebuild most of it anyway and tying new work into failing material. We tell you which side of that line you are on, in writing, with the core samples to show why.

Flat roof repair cost in Hamilton

No competitor on page one of this search publishes a number. These are typical Hamilton ranges, not quotes.

JobTypical range
Leak investigation with core cut$350 to $700
Seam or flashing repair$500 to $1,500
Sectional repair including wet insulation replacement$1,800 to $4,500
Roof drain rebuilt or replaced$700 to $2,000
Scupper or parapet flashing rebuilt$900 to $3,000
Emergency call-out and temporary dry-in$450 to $1,200
Full replacement, per square foot$10 to $20
Twice-yearly inspection contractPriced per building

Four things move these numbers: how much insulation is wet, how many layers are already on the deck, access for material and equipment, and whether the work is scheduled or an emergency.

Areas we serve

We work across Hamilton and the surrounding communities.

  • the north end
  • Barton
  • Crown Point
  • Gibson
  • Landsdale
  • Corktown
  • Durand
  • Westdale
  • Ainslie Wood
  • Kirkendall below the escarpment
  • Mountain neighbourhoods above it. We also cover Stoney Creek
  • Dundas
  • Ancaster
  • Waterdown
  • Binbrook
  • Mount Hope
  • Grimsby
  • Burlington

What homeowners ask us

How much does it cost to have a flat roof repaired in Hamilton?
A seam or flashing repair typically runs $500 to $1,500. A sectional repair including wet insulation replacement usually falls between $1,800 and $4,500. Full replacement runs roughly $10 to $20 per square foot. These are typical ranges, not quotes.
Can a flat roof be repaired?
Yes. Every common flat roof membrane is repairable in place. EPDM takes primed seam tape, TPO is hot-air welded, SBS is rebuilt in two plies, and a built-up roof is rebuilt to the same ply count. The limit is the insulation underneath, not the membrane.
How do I fix a flat roof without replacing it?
Find the entry point, then rebuild that section only. A sectional repair removes membrane and wet insulation down to dry material, installs new insulation and cover board, and ties into the old membrane with a staggered lap. Coatings over a wet roof trap moisture.
Will insurance cover a 20-year-old roof in Ontario?
Ontario home insurance generally covers sudden accidental damage such as a storm or a fallen limb, and excludes wear and long-term leaks. A 20-year-old flat roof that failed from age is usually treated as maintenance, not a claim. Photograph the damage and call your broker first.
Why does water sit on my flat roof?
The roof lacks fall, or the drain is blocked. Flat roofs are built with about 2% slope toward drains or scuppers, and decks that settled or were framed level hold water. Water standing 48 hours after rain counts as ponding and adds 5.2 pounds per square foot per inch of depth.
Can a flat roof be repaired in winter in Hamilton?
Emergency work can be done in any weather, and stopping active water never waits for spring. Permanent repairs are limited by temperature, because adhesives and seam tapes have minimum application temperatures and a membrane has to be clean and dry to bond. Torch-on work carries additional cold-weather precautions. We will dry a roof in temporarily and return to complete the repair properly when conditions allow, and we tell you plainly which of the two you are getting.
How long does a flat roof last?
On a Hamilton building, expect roughly 15 to 25 years from EPDM, 15 to 25 from TPO, 20 to 30 from SBS torch-on and 20 to 30 from tar and gravel. What actually decides it is drainage rather than the membrane. A roof that sheds water within a day or two of rain reaches the top of its range, and a roof that ponds will fail early no matter what it is made of.

Flat roof leaking?

Flat roof leaking? We find the entry point, show you the core, and quote a fixed price. Serving Hamilton, Stoney Creek, Dundas, Ancaster and Waterdown.

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