Flat roofs on commercial buildings
Most commercial roofs in our area are low-slope membrane roofs, and they fail for the same reasons residential flat roofs do, just with more roof and more at stake: water that sits instead of draining, seams that open, flashing that cracks at parapets and curbs, and penetrations that were never properly sealed. The fix is rarely just a dab of sealant. It is working out why the water got in and whether the membrane, the drainage or only one detail is the problem.
What we do
- Leak tracing and repair. Open seams, split flashing, failed penetrations and punctures, found from the roof rather than guessed from the ceiling.
- Membrane replacement. TPO, or torch-down and modified bitumen, installed as a continuous sealed system with the fall toward the drains done properly.
- Drainage. Drains, scuppers and ponding checked before we quote. A new membrane over a drainage problem just buys a few years and the same phone call.
- Parapets, curbs and penetrations. Vents, units and wall tie-ins flashed as part of the system. On a roof with a lot of detail, this is most of the work.
- Inspections. A look at the condition of the roof so you know whether you are planning a repair, a replacement or just routine maintenance.
TPO or torch-down on a commercial roof
The two systems we install suit different roofs. TPO is a single-ply sheet, hot-air welded at the seams so the joins become part of the same membrane. It is light, usually white or light grey so it reflects summer heat, and clean to install with no torch and no kettle. Torch-down modified bitumen is two plies of asphalt-based membrane, the cap sheet fused to the base. It is tough, takes foot traffic well, and copes with awkward geometry and roofs that have been patched by several different people. Which one suits your building depends on the deck, the drainage, how much sun it takes and what is already there. The residential version of this explanation is on our flat roofing page.
How a commercial quote works
We do not quote roofs over the phone or from satellite images. We come out, get on the roof, check the membrane, the seams, the drainage and the flashing details, and leave you a written quote. It is free, and there is no obligation to book. It helps if you can tell us the roof's approximate age, what is leaking and where, and who needs to approve the work, whether that is an owner, a property manager or a landlord.
Membrane work wants a dry deck and reasonable temperatures, so the warm months fill up first. If a roof is leaking now, call as soon as you notice it rather than waiting for the season to turn.
Where we do commercial work
Most of the commercial calls we get are in Georgetown, Acton and Cambridge, and we work across the rest of the area listed below, including Kitchener and Waterloo. If your building is somewhere else, call and ask. We will tell you straight whether we cover it.
Keeping a commercial roof in shape
A roof that gets looked at once a year or so costs less over its life than one that is only looked at when it leaks. A yearly inspection and tune-up catches the cheap problems, like a lifted flashing, a blocked drain or a loose penetration, while they are still cheap. For houses and small buildings with shingles, see roof repair and leak detection.
Common questions
What kinds of commercial roofs do you work on?
Flat and low-slope roofs: retail units, offices, shops, garages and similar buildings. The systems are the same ones we install on residential flat roofs, TPO single-ply and torch-down or modified bitumen, applied to a larger roof. Call us with the building and roof size and we will tell you whether it is a fit before anyone drives out.
Should I repair or replace a commercial flat roof?
A repair makes sense when the damage is local, such as an open seam, cracked flashing at a parapet or a failed penetration, and the membrane around it is sound. Replacement is the honest answer when the membrane is blistered or splitting across the roof, the insulation underneath is wet, or the same roof keeps leaking in different places. We tell you which one we think it is, and why, at the quote.
TPO or modified bitumen for a commercial roof?
TPO is a single-ply sheet, hot-air welded at the seams, light in colour so it reflects summer heat, and clean to install. Torch-down modified bitumen is two plies fused together, tough underfoot and forgiving around parapets, tight corners and many penetrations. Where the roof is a big clear area TPO is often the better fit; where it has a lot of detail, torch-down often is. We say which we would use on your roof and why.
Do I need a building permit to replace a commercial roof?
It depends on the building and on what is changing. A like-for-like membrane replacement often does not, but a change to the structure, the insulation or roof assembly, or the drainage can. Commercial buildings can also carry landlord, insurer or fire-rating conditions. Your municipal building department has the final word, and we will flag what applies to your roof when we quote it.