Commercial metal roofing for Ontario businesses and institutions

The commercial metal roofing work we take on

The commercial work we quote is standing seam metal on buildings where the roof is sloped, visible or both, such as retail plazas with sloped mansards and entry towers, offices, clinics, churches, schools and municipal buildings, lodges and resort buildings, restaurants, and heated shops and showrooms. It also includes the parts around the roof that are made from the same coil, such as parapet coping, canopies, fascia bands, and the facade panels that front many newer commercial buildings.

Our guide to commercial standing seam covers the engineering in depth: long panel runs and thermal movement, drainage and overflow, rooftop equipment and curbs, drift loads and weathertightness warranties. What follows is how a commercial job with CGD actually runs, and which buildings we are and are not the right trade for.

Low-slope roofs: double-lock seams, and where metal stops

A lot of commercial roof area is pitched just enough to drain and not much more. On those planes we use the 180° double-lock seam with sealant in the seam, which is the detail that lets standing seam work on slopes down to roughly 1:12. The seam is folded twice by a mechanical seamer, so water sitting against it on a shallow pitch has no easy way through.

Below that, and on any genuinely flat roof with internal drains, metal panels are the wrong product. Those roofs belong to a membrane contractor. Where a building combines both, such as a flat membrane core surrounded by a sloped metal mansard, the junction between the two systems needs a clear owner, and we would rather settle who that is before the work starts than after the first leak.

Parapet coping, canopies and fabricated metal

On many commercial buildings the custom sheet metal matters as much as the field panels. Parapet coping has to shed water outward to the face of the wall and inward to the roof, lap or join at the corners without relying on sealant alone, and be fixed so wind cannot lift it. Canopies over entrances need their own drainage so they do not drip on the people walking under them. Fascia bands, gravel stops, scupper boxes and transition flashings all need to match the profile and colour of the roof.

We bend those parts on our brake, to site measurements and from the same coil as the panels, so colour and finish match rather than being sourced from a different batch. Coping replacement is also a project in its own right: on many older flat-roofed buildings the membrane is fine but the coping is loose, rusting or leaking at the joints, and new coping is the repair.

ACM panels and metal facades

Aluminum composite material (ACM) is the flat, rigid panel you see on storefronts, dealerships and institutional entrances. It is a different product from standing seam: routed and folded into cassettes, hung on a subframe, with joints that are either open as part of a rainscreen or sealed, depending on the system. We supply and install ACM facades alongside metal roofing and standing seam wall cladding, which lets a single trade handle the roof edge, coping and wall panels where they meet.

Fire performance requirements for wall cladding depend on the building, its height, its occupancy and its distance to other buildings. Those requirements come from the design team and the building permit, and the panel and core specified must match what the drawings call for. We build to the specification; we do not choose a cladding core on a commercial building by price.

Working from drawings, specifications and tenders

Commercial jobs come to us in a few ways: an owner with an existing building that needs a new roof, a general contractor pricing a tender, or an architect who wants input on a metal detail before the drawings are final. In each case the most useful first contact is paper rather than a phone description. A roof plan with slopes, sections at the eaves and parapets, the existing assembly if it is a retrofit, any rooftop equipment, and the specification section for the metal roofing if one exists.

Back from us comes a written specification and price that lists gauge, seam, finish, clip layout, underlayment, every fabricated detail, snow retention, exclusions and the warranty that actually applies. Where a tender calls for a particular manufacturer system or warranty, tell us at that stage. It may change what we can offer, and finding out before bid day is better for everyone.

Sequencing work on an occupied building

Most commercial re-roofs happen over a business that stays open. That means the schedule is built around the occupants as much as around the weather. We agree in advance where the roll former, bins and material sit so they do not block customer parking, fire routes, loading docks or deliveries. Work over entrances is planned for quieter hours or protected with hoarding, and any area under active work is closed off at ground level.

On a retrofit, the roof is opened only in sections that can be closed to weather by the end of the day. Rooftop units, exhaust fans and other equipment that has to be disconnected or lifted are coordinated with the building's mechanical contractor, who is usually not us. Noise from tear-off is real, so a building with sensitive occupants, such as a clinic or a school during exams, gets the loudest work scheduled for when it will do the least harm.

Agricultural buildings and outbuildings: when we are not the answer

We get many calls about farm buildings, storage buildings and detached shops. On an unheated drive shed, hay barn or cold storage building on purlins, exposed-fastener metal is often the right roof. It costs much less, goes on quickly, and the re-screw it needs eventually is a manageable job on a low, walkable roof. We will tell you that on the phone rather than sell a premium system to a building that does not need it.

Standing seam starts to earn its cost on the heated and finished ones: a shop with an office and insulation, a farm store or event barn that the public sees, a tall bank barn where re-screwing means staging and fall protection, or any roof with solar planned. Those are the agricultural roofs we quote.