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
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
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.
Residential flat roof repair services in Hamilton
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.
- 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.
- Surface survey. We walk the roof, probe every seam and flashing, and mark soft areas.
- 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.
- Written scope. You get the membrane, the area and the insulation to be replaced, at a fixed price.
- 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
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.
| Job | Typical 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 contract | Priced 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.
Flat roof leaking?
Email usAreas we serve
We work across Hamilton and the surrounding communities: the north end, Barton, Crown Point, Gibson, Landsdale, Corktown, Durand, Westdale, Ainslie Wood and Kirkendall below the escarpment, and Mountain neighbourhoods above it. We also cover Stoney Creek, Dundas, Ancaster, Waterdown, Binbrook, Mount Hope, Grimsby and Burlington.
What sits between the membrane and the deck
Most Hamilton flat roofs built or re-roofed in the last thirty years carry polyisocyanurate insulation, usually with a cover board above it and a vapour retarder below.
The cover board above it is what stops foot traffic and hail from crushing the insulation into the deck. Roofs that were built without one, or where the board has been broken up by years of rooftop unit servicing, show it as soft spots underfoot long before the membrane fails.
Below all of it is the deck, which in Hamilton is steel on the commercial and industrial stock, concrete on some mid-century buildings, and wood plank on the century-house rear additions. The deck decides what can be done. A wood plank deck that has been wet for years does not take a mechanically fastened system, because the fasteners have nothing left to hold.
Fixing the fall, not just the leak
A roof that ponds will pond again after a repair, because the repair does not change the slope.
Adding drains or scuppers is sometimes cheaper than tapering. On a small residential flat roof with one blocked internal drain, a second outlet at the low corner solves more than a full tapered package would.
We say which of the three applies before quoting, because a sectional membrane repair on a ponding roof is the repair most likely to come back.
Snow, ice and the Hamilton winter
Winter is when a Hamilton flat roof carries loads and stresses it sees at no other time.
Snow does not sit evenly. It drifts against parapets and rooftop units, so the load concentrates exactly where the membrane is already detailed and vulnerable. Wet snow is far heavier than fresh snow, and a roof carrying a foot of saturated snow after a thaw is carrying several times the weight it carried the week before.
Clearing snow is delicate rather than heavy work. Metal shovels and ice chippers cut membranes, and a repair caused by clearing is common enough that we would rather clear the drains and leave a snow layer than strip the roof to the membrane.
Membrane warranties, and what they actually cover
Warranty length is the most misread number in this trade, and the misreading is usually in the customer's disfavour.
Three things are worth reading before you rely on either. Material warranties are frequently prorated, so year eighteen pays a fraction of year two. Both are usually void if another contractor works on the roof. And a manufacturer's system warranty, the kind that does cover installation, generally requires a certified installer and a full system of that manufacturer's components, which a sectional repair on an existing roof cannot produce.
What a written condition report should contain
Property managers ask what separates an inspection from a walk-around, so here is the standard we work to.
A usable report names the membrane type and its approximate age, records the deck type and the number of layers found, and states drain and scupper condition individually rather than collectively. It maps soft areas and ponding locations against a roof plan. It carries dated photographs of every defect it claims. It separates what needs doing now from what can wait a season, and it prices those separately.
Twice-yearly inspection in spring and autumn catches the two things that matter: winter damage before the summer storms, and blocked drains before the winter.
What homeowners ask us
How much does it cost to have a flat roof repaired in Hamilton?
Can a flat roof be repaired?
How do I fix a flat roof without replacing it?
Will insurance cover a 20-year-old roof in Ontario?
Why does water sit on my flat roof?
Can a flat roof be repaired in winter in Hamilton?
How long does a flat roof last?
What is the difference between a flat roof repair and a recover?
How long does a flat roof repair take?
Does a flat roof need to be replaced if the insulation is wet?
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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