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Markham Commercial & Technology Flat Roofing
Flat Roofing Markham, Where a Leak Costs More Than the Roof
Find out which bays sit over equipment you can't afford to get wet, and what shape each one is in, before the capital budget gets set.
50 years · Founded 1977 | 4.8 on Google | Own crews, never subcontracted | Licensed, insured · WSIB covered | Free spring & fall inspection
Nineteen Business Parks, and What They Hold
Markham names nineteen business parks on its own map — Commerce Valley and Galleria, Markham Centre, 404 North, Fourteenth Avenue, Thornhill, Thornlea, Denison/Steeles, Woodbine/Apple Creek and the rest. What sits inside them is the reason this page reads differently from the other twelve.
York Region's 2024 employment survey counts 9,899 businesses and 184,645 employees in Markham, with professional, scientific and technical services the largest single sector at 31,290 employees across 1,179 companies. The City's own figures describe over a thousand technology and life sciences companies and put the technology workforce at around 37,000. Those two counts do not agree, because they measure different things over different years — but either way, the shape is clear.
It is not only offices. Markham carries real colocation capacity: Digital Realty's facility on Gough Road runs to about 104,500 square feet on a ten-acre site, Cologix opened a fifteen-megawatt building on Clegg Road, and Equinix operates a site on Warden Avenue. Most of these are single-storey, which is the detail that matters here.
Single-storey means there is no floor between the roof and the thing underneath it.
So on a fair number of Markham buildings, the membrane is the only barrier between weather and equipment that a business cannot operate without.
Who's asking to get on your roof
Own payroll
Everyone who signs in at your front desk works for Crown. No labour brokers, no rotating subtrades.
Since 1977
Commercial and industrial flat roofs for fifty years, and never a single house.
Markham / Thornhill
Two jobs on file in our gallery, from July and September 2024.
4.8 on Google
Our Google rating. See what two clients wrote, further down.
Stop Asking How Old the Roof Is
Most roof planning starts with a number: the roof is eighteen, the expected life is twenty, so it goes on next year's capital list. On an ordinary warehouse that logic is fine. Over a data hall or a laboratory it is close to useless, and occasionally dangerous.
Two buildings, both with a twelve-year-old membrane in identical condition. One is a dry-goods warehouse. If it leaks, someone puts a bucket under it and calls a roofer on Monday. The other is a colocation facility. If it leaks, water finds energised equipment, and what follows is measured in customer contracts rather than in square feet of membrane.
Same roof. Completely different problem. And age told you nothing about either.
The honest scale of the second case is worth stating carefully. Industry survey work on data centre operators has found that more than half of significant outages cost over a hundred thousand dollars, and around one in five exceed a million. Those figures cover outages from every cause — power, network, cooling, everything — not roof leaks specifically, and it would be dishonest to present them as a roofing statistic. What they do establish is the order of magnitude that a wet ceiling over a data hall is playing against. Against numbers like that, a roof assessment is not a cost.
So on these buildings we ask a different question. Not "how old is it" but "what happens if this fails, where would it fail first, and how would we know before the people downstairs do?"
That reframing changes real decisions. It changes where you spend a maintenance budget — on the twenty per cent of the roof directly over critical space rather than evenly across the field. It changes the inspection interval, because a building where failure is expensive earns more frequent looks than one where it isn't. It changes how you treat a small, non-urgent defect over a server room, which is not small at all. And it changes the replacement trigger, from "the roof reached its expected life" to "the condition and the consequence together say now" — which is sometimes earlier than the calendar suggests and quite often later.
That last point is worth dwelling on, because it cuts both ways and most contractors only tell you the half that sells a roof. A sound twelve-year-old membrane over a data hall may well warrant monitoring and a targeted programme rather than a tear-off. How a roof inspection report should read is the tool for deciding that — and if a report you have been handed does not let you make that distinction, it is not a report, it is a quote with photographs.
Knowing Before the People Downstairs Do
There are three levels of early warning available on a roof, and most buildings use none of them.
The first is thermal. Scanning it thermally after dark shows wet insulation as warm against a cold dry field, which finds saturation that has not yet become a leak and maps how far an existing one has travelled. On a critical building this is the minimum, and it should be on a schedule rather than done once in a panic.
The second is electronic leak detection, which most owners have never heard of and which is genuinely different from thermal scanning. Rather than looking for moisture that has already collected, it looks for the breach itself — the hole. There are recognised standards covering it, and two broad methods: a low-voltage technique run on a wetted membrane that traces current to a defect, and a high-voltage technique used on a dry membrane. Both have a hard requirement worth knowing before anyone sells it to you: they need a non-conductive membrane over a conductive deck. A conductive black rubber membrane cannot be tested this way at all, and overburden on top of the membrane degrades the result. The industry body that publishes guidance on it is also clear that it does not replace ordinary visual inspection — it supplements it.
The third is permanent monitoring. Sensor grids laid across the membrane, which report moisture continuously rather than when somebody remembers to look. In some Canadian guarantee programmes these are mandatory on waterproofing assemblies and must go in before any overburden is installed — which is the key scheduling point, because once pavers or a green roof are down, that option has gone for a generation.
None of this is exotic and none of it is expensive relative to what it protects. What it requires is deciding at the right moment, which is when the roof is open or being specified — not after a leak has already introduced everyone in the building to each other.
Whatever is chosen, it only works with a maintenance programme with records behind it sitting underneath it.
The Crown Consequence-First Survey
How we get from “the roof is twelve” to a plan your facilities and finance people can both work from.
1. Start underneath
We walk the floor with your facilities lead first and mark what sits under each bay.
→ The roof gets ranked by what it protects, not by its age.
2. Scan after dark, core where it counts
Infrared picks out wet insulation against the dry field. Cores go in where the stakes are highest.
→ Real condition data on the bays that matter most.
3. Put it on paper
Bay by bay, a written call: watch it, fix it now, or leave it alone.
→ A report you can hand to whoever signs off the spend.
4. Plan the work around your operation
If something needs doing, we size bays to close the same shift and schedule them with your operations team.
→ No open deck over a room that can't stop.
Replacing a Roof Above a Room That Cannot Stop
When replacement is the answer, the work itself has to respect what it is above.
The governing rule is that the deck is never left open. We work in bays sized so that whatever we open is torn off, dried in and watertight within the same shift, with the weather checked against that window rather than against the week. Over critical space we tighten that further and we do not start a bay we cannot close.
Temporary protection goes in below as well as above. On a data hall or a lab, coordination with the operations team is not a courtesy — they will want to know which racks or benches sit under which bay, on which day, and they will often want their own covering in place. Good buildings already have a procedure for this. We work to theirs.
Fastening and vibration matter more here than elsewhere, and it is worth raising early rather than discovering. Mechanically fastened assemblies mean impact into the deck above equipment that does not enjoy it; where that is a concern, adhered systems change the conversation. That is a decision to take with the facility's engineers before the spec is fixed.
On system choice, a PVC assembly is usually the right answer on this stock — welded seams give a continuous sheet with no reliance on adhesive tape at the laps, it details cleanly around the dense mechanical these buildings carry, and it is the membrane most compatible with the leak-detection methods above. Material warranties run up to twenty years. Where the deck is concrete and redundancy matters more than anything else, SBS modified bitumen's two welded plies are a strong argument, and we install those ourselves.
As always: we do not install TPO or EPDM, though we service both. And the full tear-off is not negotiable — over critical space least of all, because recovering means accepting that you will never again know what is happening between the layers above your equipment.
Before you call: what facilities teams usually need from us
Our security and vendor process is strict.
Good. The crew you approve is the crew that turns up, and our insurance and WSIB certificates are available whenever your onboarding asks for them.
Operations will want a say in timing.
They should have it. We work to your site procedure, and a bay over critical space doesn't get opened unless it can be closed that shift.
Leadership won't approve anything without paper.
Each visit ends in a written report, and it's detailed enough to support an internal approval.
Repair, Maintenance and Choosing Between Roof Systems
Most of what we do on Markham buildings is not replacement. It is roof repair, planned maintenance and the unglamorous work that keeps a sound membrane sound for another decade.
Repair on a critical building follows a different order from the same work on a warehouse. The first question is not where the water is showing but what sits under the affected bay, because that determines how fast we have to move and how much temporary protection goes in underneath before anyone lifts a sheet. Once that is settled the work is ordinary: find the breach properly rather than patching the stain, cut back to dry insulation, rebuild the detail, and photograph the lot for the file.
The upkeep side is where the real value is, and it is cheap. Twice-yearly roofing inspections, drains cleared before the autumn rain, every penetration photographed, walkway pad kept in place, and a written record that lets you see the same curb across four years instead of four separate visits. On a building where the consequence of failure is high, that record is also the thing that tells you when the calculus has changed.
Choosing between roof systems is the third question and it is genuinely open. PVC single-ply is our default on this stock for the reasons above. SBS modified bitumen earns its place where redundancy matters more than anything else, and hot-applied BUR still suits some of the older industrial stock in the Denison and Steeles parks. What decides it is the building, the deck, the traffic and what sits underneath — not what a contractor happens to be certified on.
A full roof replacement is simply the end of that conversation rather than the beginning of it. When it comes, it should come because the condition and the consequence agree, and you should be able to point at the report that says so. Anyone quoting a tear-off on a Markham building without a scan behind it is guessing with your capital budget.
The quality of the original installation is the single biggest predictor of all of this. A well-built membrane in Ontario will outlast a badly built one by a decade or more on the same building, in the same weather, under the same traffic — which is why we would rather talk to you about workmanship than about brands.
One practical test before you hire anybody. Ask the roofing firm for a sample survey report — not a quote, a report. A roofing company that surveys properly will have one it is proud of and will send it the same day. That document tells you more about the roofing you are going to get than any list of manufacturer certifications on a website.
Flat Roofers, Not a General Roofing Contractor
It is worth stating the boundaries of what Crown sells, because the words roofing contractor cover an enormous range of businesses across the GTA.
We are commercial flat roofers. Industrial and institutional low-slope work only. We do not do houses, we do not fit shingles, we do not do siding or eavestrough, and we do not do skylight installation — if you need a skylight put in, we will tell you who does that properly rather than take it on. We are not a TPO or rubber-membrane installer either, although we service both where a building already carries one.
What we do instead is every part of a commercial flat roofing programme: survey and thermal scanning, roof repair, planned upkeep, tear-off and full replacement, and new work alongside a general contractor. Those roofing services are the whole business and have been since 1977.
That matters more on a data hall or a laboratory than it does anywhere else. The roofing specialists who work on these buildings need to understand fastening and vibration, deck types, access control and why a bay that cannot be closed today does not get opened today. Generalist roofing contractors are perfectly competent at the work they do most of the time. This is simply not the work they do most of the time.
It also means the crew on your building is ours. No brokered labour, no rotating subcontractors through a secure facility, and the same people back for the inspections afterwards. On a site with a sign-in procedure and equipment nobody is allowed to touch, knowing exactly who is on the roof is part of the service rather than an extra.
Two Markham Flat Roofing Jobs, and a Company That Does Nothing Else
Crown has done commercial and industrial flat roofing and nothing else since 1977. Brian Sharp founded it, Joe Ferrier runs it, and the crews are ours rather than whichever subtrade was available that week — which on a building with restricted access, a sign-in procedure and equipment nobody is allowed to touch is not a small thing.
Markham and Thornhill appear twice in our project gallery, September 2024 and July 2024. Our Markham and Thornhill work is filed there by city and month, with photographs taken on the roof.
For a critical facility, though, the conversation that matters is not about photographs. It is a walk with your facilities lead, a look at what sits under which part of the roof, and an honest answer about what we would watch, what we would fix now, and what we would leave alone.
That last category is usually larger than people expect, and saying so has kept us in business for half a century.
We have been roofing Markham's business parks for a long time, and the pattern barely changes: a building calls about a stain, the scan says four curbs and a bad transition, and the tear-off everybody assumed was due gets deferred five years on the strength of a proper report. That is what fifty years of doing one kind of roofing buys you. The quality of the diagnosis decides the size of the cheque, and on these buildings the diagnosis is almost always cheaper than the assumption.
It is also why we would rather be judged on the roofing we did not sell you than on the roofing we did. A roofing company that only ever recommends the biggest job available has told you something about how it makes its money. Ask for the report, read what it says about the parts of the roof that are fine, and judge the quality of the thinking from there.
What Clients Have Written About Our Flat Roofs
Our business in Aurora had several leaks in the roof to our shop. Crown Roofing was amazing to deal with. Their worker Arvin was such a great guy and was really thorough in explaining where all the leaks were. He took photos to show us where the leaks were coming from. They also found a forth leak and fixed it in good faith without billing us. I can not express just how much we loved working with Arvin.
Amanda Helps · Google review
I waited for all seasons before giving this review as I wanted to give a transparent and accurate review. I received multiple quotes and decided to use them to replace the roof on our building.
Susan Mahabir · Google review
Rated 4.8 on Google.
Permits, Live Data Halls, Leak Detection and Young Roofs
Who actually does the work on site?
Our own crews. Crown does not broker labour and does not run subcontracted roofing crews through a client's building, which on a secure Markham facility with sign-in procedures and restricted areas is usually the first thing facilities managers ask about. The foreman on your roof is a Crown foreman, the same crew comes back for the inspections, and there is no layer of middlemen between you and the people doing the work. It also means our own crews carry the same details from building to building — the way a curb gets rebuilt, how a built-up flashing is terminated, what we do where a structural member penetrates the deck — rather than each subtrade bringing its own habits. Buildings like yours get a crew that has done a great many of them.
Do we need a building permit to re-roof a commercial building in Markham?
Probably, and Markham is stricter on this than Toronto — which catches out owners who have buildings in both. The City's list of work that does not need a permit is headed explicitly as housing projects, and the roofing item on it refers to replacing roofing or shingles on a house. There is no published exemption for industrial, commercial or institutional low-slope work, and the City states that a permit is needed whether the work is interior or exterior. Applications go through the City's ePLAN system; paper submissions are not accepted. We confirm the requirement against your actual scope before quoting, and we prepare and file where one is needed.
Can you replace a roof above a live data hall?
Yes, and the plan matters more than the roofing. We work in bays small enough that anything opened is closed and watertight within the same shift, we do not open a bay we cannot close, and we watch the forecast against that window rather than the week. Your operations team will want to know what sits under which bay on which day, and will usually want their own protection in place below — we work to your procedure, not ours. One thing to raise early: mechanically fastened systems transmit impact into the deck, which some equipment tolerates poorly. If that is a concern in your facility, an adhered assembly changes the picture, and that is a decision for your engineers before the specification is fixed.
What is electronic leak detection, and do we need it?
It is a method that finds the breach in a membrane rather than the moisture that has collected from it, using either a low-voltage technique on a wetted membrane or a high-voltage one on a dry membrane. It is genuinely useful on high-consequence buildings — but it has real limits you should know before anyone sells it to you. It requires a non-conductive membrane over a conductive deck, it cannot test a conductive black rubber membrane at all, and anything sitting on top of the membrane degrades the result. It also does not replace an ordinary visual survey; the guidance from the industry body that publishes on it says so directly. Whether your building is a candidate depends on the assembly you have, and we will tell you honestly if it is not.
Our roof is only twelve years old. Why would we assess it now?
Because on a building with critical space underneath, age is the least informative thing about a roof. A twelve-year-old membrane can be in excellent condition, in which case the assessment tells you to leave it alone and gives you a baseline to measure against later — which is worth having. Or it can have a drainage problem, a run of poorly detailed penetrations, or saturation spreading quietly from a curb, none of which announce themselves at twelve years and all of which are far cheaper to deal with now. The point of assessing early is not to find a reason to replace it. It is so that the decision, whenever it comes, is made on evidence rather than on a leak. And if something does fail in the meantime, you can reach somebody at three in the morning rather than a voicemail box.
Map the Risk Before You Budget the Roof
If your building has a data hall, a laboratory or a clean process under it, the first useful document is not a replacement quote. It is a map of what is above what, which parts of the roof carry the most consequence, and what condition each of them is actually in.
Call (416) 744-7788 or email info@crownroofing.ca. We will walk it with your facilities team, scan it, and give you that map — along with an honest view of how much of the roof needs nothing at all.
We cover Markham and the rest of York Region — Commerce Valley and Galleria, 404 North, Fourteenth Avenue, Thornhill and Woodbine/Apple Creek — and the roofing services are the same wherever the building sits: survey, thermal scanning, repair, planned upkeep and full tear-off. If you run several sites across the GTA we will assess them together and give you one schedule rather than five disconnected quotes.
One more thing about specifying a roof, because it comes up on every tech campus we walk. The roofing decision on a single-storey building over critical space is really three decisions: the membrane, the attachment method, and how you will know when something has gone wrong. Most firms quote the first and leave the other two to chance. On a Markham data hall the attachment method is an engineering conversation with your own consultants, and the monitoring decision has to be made while the roof is open, because afterwards it is gone. Getting all three right is what separates a twenty-five-year roof from a fifteen-year one, and it costs almost nothing extra at the specification stage. We will put all three in the quote in writing, with the programme that follows it — the survey schedule, who attends, and what the report will contain — set out on the same page rather than sold to you again in eighteen months.
Two things are worth saying plainly before you call anybody. Quality of installation beats brand every single time, and no guarantee document has ever kept water out of a building. And commercial low-slope work is a different trade from residential roofing — if the firm bidding your data hall also fits pitched roofs and does small domestic jobs at weekends, ask how many flat roofs like yours they finished last year in Ontario. Ours is the only answer we have, because this is the only thing we do.
Crown Industrial Roofing · 227 Queens Plate Dr Unit #3, Etobicoke, ON M9W 6Z7
If procurement needs our certificates before the site walk, ask and they're yours.
✓ Spring & fall inspection, free · ✓ Licensed · general liability · WSIB covered · ✓ Safety-certified crews, all on our payroll · ✓ Manufacturer-backed warranties on materials + a workmanship warranty of up to 15 years, issued in writing at final inspection