Commercial Metal Roofing in Toronto and the GTA
Standing seam and low-slope metal roofing, repairs and replacement for commercial and industrial buildings.
Commercial metal roofing covers standing-seam panel roofs on sloped commercial buildings and low-slope metal on industrial structures. Metal sheds water and snow well and suits long uninterrupted runs, while membrane systems suit dead-flat roofs with heavy rooftop equipment. NorthCan Roofing installs and repairs both across Toronto and the GTA. Call 416-456-0777.
What is standing-seam metal roofing?
Standing seam is a panel system where adjacent panels are joined by a raised, mechanically seamed or snap-locked vertical rib that sits above the water line. Fasteners are concealed in clips under the seam, so nothing penetrates the water plane in the field of the roof. Those clips allow the panel to expand and contract along its length, which matters in a climate that swings across a wide temperature range between a January night and a July afternoon.
The alternative, exposed-fastener profiles, screws through the face of the panel into the structure. It is quicker and cheaper to install and remains common on agricultural and utility buildings, but every screw is a penetration with a gasket, and those gaskets are what fail. A large share of metal roof leaks we attend on exposed-fastener roofs are simply hundreds of tired washers and elongated screw holes.
On commercial buildings we specify concealed-fastener standing seam wherever the slope, the budget and the structure allow it, and detail the eaves, ridges, valleys, hips, wall abutments and penetrations in matching metal rather than sealant.
Can metal be used on a low-slope roof?
Yes, within limits, and the limit is slope. Every metal panel profile has a minimum slope below which it should not be used, because the seam relies on water moving off the roof rather than sitting on it. Below that threshold, a mechanically seamed panel with a sealant in the seam is required, and below that again, a membrane system is the correct answer.
Low-slope metal is common on older industrial buildings across the GTA, often over a purlin structure with no deck. Typical issues are seam capillary action and back-up at the eave, thermal movement tearing at fixed points, corrosion at the laps and at cut edges, condensation on the underside where there is no vapour control, and ice damming at gutters and eaves during a Toronto thaw. Retrofitting insulation and a vapour barrier to an uninsulated metal roof is a design exercise, not a patch.
Where a low-slope metal roof is failing across the field, two paths are common: a full metal re-roof, or a retrofit assembly with insulation and a single-ply or SBS membrane installed over the existing panels. We assess the structure, the corrosion and the drainage before recommending either. See flat roof replacement for the membrane route and industrial roofing for large-span buildings.
Metal or membrane: which suits your building?
They are not competitors so much as answers to different questions.
- Slope. Dead-flat and shallow low-slope roofs belong to membrane systems. Anything with real pitch is a candidate for metal.
- Rooftop equipment. Dozens of units, curbs and pipes are far easier to flash into a membrane. A metal roof with many penetrations loses much of its advantage.
- Foot traffic. Membrane assemblies with a cover board and walkway pads take service traffic better. Metal panels dent and the finish scars.
- Appearance. Standing seam is a visible architectural element on street-facing elevations, mansards and canopies, and pairs with the metal cladding described on roof flashing and siding.
- Snow. Metal sheds snow, which is useful on a pitch but means snow guards are needed above doors, walkways and parking. Membrane roofs hold snow, which is a load question rather than a shedding one.
- Repairability. Membrane repairs are straightforward and local. Metal repairs often mean replacing panels or reworking a seam run, which is more involved.
The full membrane comparison is on flat roof types.
On many GTA buildings the answer is both. A sloped street elevation or a mansard in standing seam, and a low-slope membrane behind it over the main structure, is a common arrangement, and the junction between the two is where the detailing has to be right.
What metal roof work do you carry out?
Our metal work spans repair, component replacement and full re-roofing.
- Leak investigation and repair at seams, laps, fasteners, penetrations, curbs and wall abutments.
- Fastener replacement programmes on exposed-fastener roofs, upsizing screws and replacing washers where the original holes have elongated.
- Flashing and trim replacement at ridges, eaves, gables, valleys and wall junctions, formed in matching profile and finish.
- Eavestrough, downpipe and snow guard work, including correcting the ice-damming conditions that come with a Toronto winter.
- Panel replacement where sections have been damaged by wind, impact or corrosion.
- Full metal re-roofing, including underlayment, ventilation and thermal detailing appropriate to the building.
- Retrofit membrane over metal, where the panel roof has reached the end of its service and a low-slope assembly is the better long-term answer.
Metal work sits alongside our low-slope services on commercial roofing, and completed work is shown in the gallery.
How do you get a metal roof assessed?
Call 416-456-0777 or use the contact page. We attend, walk the roof where it is safe to do so, examine the seams, fasteners, flashings and drainage, look at the underside for condensation and corrosion where access allows, and return a written quote for the work needed. If you want a documented file for a capital plan instead, order a roof condition report.
Work at heights on a pitched metal surface is carried out under the Occupational Health and Safety Act and the Ministry of Labour, Immigration, Training and Skills Development working-at-heights requirements, with anchor points and fall-arrest suited to the panel system. WSIB coverage and certificates of insurance are provided on request.
Frequently asked questions
Why does our metal roof leak at the screws?
Exposed-fastener panels rely on a rubber washer under each screw head. Washers harden and crack with ultraviolet exposure and temperature cycling, and repeated thermal movement gradually elongates the hole so the screw no longer seats. The remedy is a fastener replacement programme with oversized screws and new washers, not a bead of sealant over each head.
Can a metal roof be installed over the existing one?
Sometimes, using a sub-purlin or hat-channel retrofit framing system over the old panels. It avoids tear-off and keeps the building closed in, and it creates a cavity that can take insulation. It depends on the condition and capacity of the existing structure, so the added load is confirmed before anything is specified.
Is a metal roof noisy in rain?
Far less than people expect on a commercial building. Noise comes from panels installed over open framing with nothing behind them. Over a deck with insulation and underlayment, or in a retrofit assembly with a filled cavity, rain noise is not usually a complaint we hear from occupants.
What causes condensation under a metal roof?
Warm humid interior air reaching the cold underside of the panel, where it condenses and drips. It is very common in uninsulated or poorly vapour-controlled industrial buildings and is often mistaken for a leak. The clue is that it appears on cold clear days rather than during rain. The fix is thermal and vapour control, not sealant.
Do you install residential metal roofs?
No. NorthCan Roofing works on commercial and industrial buildings only. Our metal work covers commercial standing seam, low-slope industrial metal, cladding and associated flashing and trim.
Ready for your free roof assessment?
Tell us the address, the roof size and what you are seeing. We will book a time to get up there and put it in writing.
Call 416-456-0777 to book. Roof leaking right now? Our 24/7 emergency line is 416-450-1818.
Call 416-456-0777