Monday, January 31, 2011

Flat and Commercial Roof Snow Removal

Flat Roof Snow Removal | Commercial Roof Snow Removal, Roof Ice Removal, and Flat Roof Drainage
Commercial Roof Snow Removal

Removing Snow on a Commercial Flat Roof - Commercial Roof De Icing and Roof Ice Dam Problems

Removing snow and ice from a commercial roof is a job for a trained and experienced tradesperson.

Below is also guide that may assist you in a DIY or "how to" for large industrial or commercial snow removal and ice removal situations.

General Roofing Systems Canada has trained ice and roof snow removal flat roofing tradespeople in Calgary, Edmonton, Red Deer, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Kelowna, Vancouver, Squamish, and Whistler.

We also dispatch snow management and/or snow removal crews in support of situations where local companies and experts are operating at over-capacity.

Ice Dam Removal at Gutters
For emergency or large project flat roof snow and ice removal projects our commercial and industrial roof snow removal management and/or crews are dispatched to various areas of North America such as; the GTA Greater Toronto Area, Windsor, St Catharines, Kingston, Barrie, Hamilton, London, Ottawa, Ontario areas, Montreal Quebec, Halifax Nova Scotia, Winnipeg Manitoba, and pretty much anywhere there are commercial roof snow load conditions that require immediate emergency removal of roof ice and snow.

With this most recent storm that moved up from the USA in to Toronto, Montreal, and on to Halifax, we are now logging calls for Roof Snow Removal Expertise in the USA for Industrial and Commercial Roof Snow Removal in Connecticut, Pittsburgh, Cleveland, Pennsylvania, New Jersey, Rhode Island, Maine, Hartford, New York, Washington, Vermont, Buffalo, etc.

From the Springfield News, "There are between two and three feet or more of ice and snow across Western Massachusetts. On many roofs, crews aren't just dealing with the white fluffy snow. They're also dealing with a layer of ice from Wednesday morning's storm, as well as, another layer of ice from several weeks ago."

From the Connecticut "DAILY ITEM";

"There have been roof collapses in Avon,
Worcester and four in Connecticut, and he
is sure there will be more before winter
fades into spring."

Industrial Roof Snow Removal Project
Our expertise and experience in the discipline of Emergency Commercial Roof Snow and Ice Removal has our in house specialists dispatched to attend sites wherever required in a consultancy or emergency management capacity.

Travel and lodging is typically inexpensive relative to the scope of work and tasks at hand, and our management and crews can mobilize, engage a local workforce, and be active on site anywhere in less than 24 hours.

Click for our Main Web Site Page on this topic and services available.

For emergency roof snow service and dispatch 24 hours call +1.877.497.3528 or +1.403.873.7663, email us at, or visit us at .

Commercial Roof Snow Loads
It is Important to take Action in Advance of the Emergency

The interesting thing about roof snow loads and ice problems and the clearing of snow and ice off flat roofs is that homeowners are much more apt to respond sooner to the need than our commercial and industrial roof snow removal clients.

"Commercial and industrial buildings are much more
susceptible to roof failure / roof damage / roof collapse
or roof leaks from lack of snow and ice removal than
residential buildings are."

The main reason for this is that commercial roofs are typically flat roofs and in some cases metal roofing systems - the spans are greater and the roofs are flatter than residential typically.

General Roofing Systems encounters every type of commercial, industrial, and residential building roof system there is, and we are still learning how to properly remove snow and ice from a commercial or industrial flat roof system.

There is a High Probability of Injury, Problems, or Structural Issues when embarking on Commercial Roof Snow and Ice Removal

Case in point - just the other day we were removing snow and ice from a five storey building (Chapters Book Store) on Whyte Avenue in Edmonton AB Canada.

It took senior field roof management hours to figure out how to safely get the ice dams and roof snow off various decks to the ground from that roof because there were so many variables involved. The client of course is wondering, why is it taking so long for them to start?

Commercial Retail Roof Snow Removal (Click to Enlarge)
  The answer is simple, and the reality is,

"There can be hundreds of variables to consider and
have checked and re-checked prior to starting a
Commercial Roof Snow Removal Project."

Considerations for Snow and Ice Removal from a Commercial Roof include and are not limited to;

Power lines, OHS concerns, pedestrian traffic, vehicular traffic, rooftop equipment of various kinds on various roof terraces, are there skylights or solar tubes covered in snow? (imagine walking right in to and through a skylight), ground spotter safety, bobcats and dump trucks operating, roof membrane considerations, window safety, roof top weight loads can become unbalanced causing a roof collapse or significant structural damage to the roof or building, calling in engineers early, shoring up structure for interim, at what point do you evacuate building, tie off points (especially if a roof collapse is of concern), proper commercial insurance, tool box meetings, fall plan documentation, site hazard assessment documentation, tool box meeting documentation, first aid, harnesses, lanyards, anchors, hard hats, proper work wear, permits, etc.

The point is clear, there are hundreds of considerations when removing ice and snow from a commercial flat roof system and far too many people just jump in to shovelling off a roof and don’t think through what can occur if the process is handled incorrectly.

The added bonus when hiring a professional roofing company is also that an experienced flat roofing company can also assess your roof while conducting ice and snow removal for any maintenance or repairs that may be required prior to the spring melt, at which time leaks will obviously occur. The roofers naturally are looking for issues with the roofing system without even thinking about it.

Ice build ups at Drains
There is a balance between Removing Ice and Damaging Your Flat Roof System

Far too many people desire ice to be removed and do so with-out considering the consequence.

The equipment and tools used to remove the ice and snow can damage the roof. Hammers, shovels, scrapers, chain saws, spiker shoes, de-icers, can cause damage to the roof membrane.

Note: We do not use snow blowers when clearing commercial or industrial flat roof systems and we do not condone the use of them at all for any roof snow removal scenario.

Ice on a Commercial Flat Roof or Low Slope Roof System

When assessing your flat roof and possible remedies, the considerations for snow and ice removal are;

Is the presence of the ice on my roof causing a structural problem with my roof? Is it a potential hazard to pedestrian traffic below? Or is it just that the ice may just cause issues with the flat roof membrane and it may leak?

"The rule of thumb when dealing with how to Remove
the Ice on your Commercial Flat Roof is to do as little as possible"

Leave alone what ice and snow that isn’t going to hurt someone, cause a major roof leak, or cause a structural failure. Removing dangerous ice overhangs, icicles, snow from on top of the ice, and making drainage paths may be all that needs to occur. Now of course, if there is a structural concern, then more aggressive action may be necessary.

From the Edmonton Sun Newspaper...

"General Roofing Systems advises that the snow isn’t as much
of the problem as is the ice build-up underneath.

Snow melts, it freezes and then is covered by a new layer of snow.
The process repeats until the ice sheet becomes too heavy for
the roof to bear.

Trouble may not show up until the spring thaw when water that
ended up freezing in the attic melts and comes through the ceiling.

Then of course there is the possibility that all that weight will
cause structural failure."

And we must not forget … remember to plan ahead!

One of the main problems people have with emergency roof snow or ice removal is that they wait too long.

It is best to engage a roofing contractor early on to assess and get them active on your file and then if emergency service is required you will naturally be closer to the front end of service considerations for the contractor as they already are aware and on top of your situation.

The Most Common Solution for Flat Roof Ice Damming

In most cases, the ice on a flat roof is dealt with by affecting proper drainage and not through complete removal. Snow can be completely removed of course, but ice is mostly handled through effective drainage considerations.

Flat Roof Ice and Snow Assessment and Removal Procedures

Industrial Roof Snow Removal
Assessing Roof Structural Damage Risk

As a general guide, and depending on where you live, most flat roof systems are constructed to safely hold a maximum of 15 – 20 cm of ice or 35 to 40 cm of hard pack snow, or about 70 to 80 cm of fresh snow - but be careful to look further in to the numbers before deciding not to take the snow off your roof.

If you are getting anywhere even remotely close to these numbers, or if you have a flat roof system or a metal low slope roof system that has large roof spans, you will need to lighten the roof load.

Checking the Depth of Snow on Commercial Roof

The trouble with assessing by depth of snow or volume is that many other factors come in to play. Who built the roof system? What was the specification? Have there been renovations below? What are the spans? How old is the roof system? We have seen roof systems collapse that had snow loads under the general guideline above.

Typically time has a lot to do with roof load capacity - we call this the fatigue factor. Roof collapse can occur easily on roof systems that have half the load as above if left for long durations, especially on flat roofs with large spanning beams.

So a "safe" amount of snow or ice on a roof is really about half of the recommended maximums if the snow or ice will be there for any time at all. And when the ice and snow does start melting, be sure a professional roofing contractor or a maintenance person is regularly checking the internal drains or scuppers to be sure the water is flowing down drains and not filling your flat roof up like a bathtub.

Snow Drifts in Excess of 10' on Industrial Roof
Other considerations with the roofs load capacity are the drifts (in some instances we have encountered drifts in excess of 10' high) and various lean-to's and such.

Also of great concern are commercial flat roof systems that have a second flat roof installed over top of another roof. Retro Fits or Roof Overlays are the process of installing a second roof over top of an existing roof. We encourage homeowners or businesses in this category to eliminate any roof ponding, snow build up, or ice damming at all just to be safe.


Ultimately, if you have a structural concern (look for signs of stress inside the building), contact a structural engineer as soon as possible.

Flat Roof Snow Removal

As noted above, there can be hundreds of considerations when removing snow from a flat roof, the main goal of course (and many folks miss this) is for everyone to go home safe and sound. We strongly encourage you not to take on the task yourself.

Commercial Flat Roof Drainage and Ice Issues

Ice expansion (lateral pressure from ice expansion) on a flat roof can cause significant damage to roof top units, parapet walls, flat roof flashings, skylights, elevator shafts, etc. To avoid damage and roof leaks you can work toward drainage maintenance steps that may help the issue.

"The goal is to separate the Ice Field on your Flat Roof from
what ice expansion may cause issue with your Flat Roof. "

Periodically as winter progresses, you may have to go to work again at this and separate the ice from the parapets etc. Once again, we recommend a professional take this on for you.

Large Flat Roof Snow Removal Project
Steps to proper Flat Roof Drainage with Ice causing issues (central flat roof drainage systems)

1. The first step is to remove the snow from the roof so that the warm roof underneath doesn’t create ice (this is true for both commercial and residential high slope roofs).

2. Use electrical cables (heat wire, heat trace) to separate an ice dam or ice field from areas that may be damaged.

3. Clear about a foot to three feet all around the roof drain areas by using hot water or non-corrosive de-icers. If you really know what you are doing you can use tools – but be careful not to damage the roof membrane.

4. Lay the electrical cables (heat wire) starting at drain and extending to each corner of the roof. Run loops around obstructions in the way such as skylights or roof top units. And place wires along parapets and wherever there is a concern with lateral ice pressure causing damage.

5. If not too cold, the cables (heat wire) will melt their way to the surface of the flat roof giving you pathways for drainage.

6. Chemical de-icers can be used in the same pattern but be sure you are using non-corrosive de-icers.

7. Hot water can also be used to cut drainage paths with some success.

8. Steam trucks are not considered by most to be an effective method.

If you have any questions give us a call anytime, we'd like to help.

And to our friends in the US that have been calling with that most recent storm, all the best, and call anytime even if it's for some help over the phone. You folks have had it tough and some of the toughest situations we've been able to assist with just with some simple knowledge has been right over the phone.

For example, we had a large industrial facility call from Connecticut and the lady on the phone was having their everyday staff go up and start clearing the snow because local contractors are way over capacity, and had those workers started with out that phone call it could have been devastating. Those workers did not know to clear in certain patterns (the roofs were larger than 750,000 sq feet each). You have to be very careful to follow engineering principles when clearing that kind of load of snow of that large of roof span. Your roof can literally become unballanced and collapse or at minimum significant structural damage can occur. The best method typically is to clear 8 - 12' around the perimeter and then 4' paths or swaths every 8' on center. But check with your structural engineer early - this should be your first call.

So, bottom line, don't hesitate to call if you're unsure. And it doesn't matter where you're from, we'll tell you what we know.

Until next time.....


The Staff at GRS.



About Us:
The staff at General Roofing Systems Canada are serious about the roofing trade and it is important to reiterate that the topics discussed above are potentially dangerous activities for those not trained and experienced.

We are family owned business people, and more importantly tradespeople.
We encourage you to allow the professionals at GRS handle your roof system concerns, especially in this particular arena of roof work.

We have veterans on staff that manage each site with many decades of experience and our staff experience is calculated in centuries and not decades. 
We cannot stress enough the dangers associated with ice and snow on commercial and industrial roofing systems. Imagine the consequence of someone not planning ahead and falling through a flat roof skylight for example.
We have a 5,000,000.00 Commercial Liability Insurance Policy, are WCB registered and are in good standing, we maintain a Lifetime Guarantee on all our work, our Roofers are Certified Roofers, and we have endless references from Fortune 500 Corporations, Property Managers, Civic, Industrial, Factories, and Government facilities. 
We service commercial flat roofing in the following communities in Western Canada; Calgary, Edmonton, Red Deer, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Kelowna, Vancouver, Squamish, Whistler and points between. And for emergency commercial flat roof snow removal and ice damming issues we can dispatch crews and/or management consultants to all points of the globe.

For Emergency Commercial Roof Snow Removal in other areas of Canada or the globe contact our head office 24 hours at +1.877.497.3528 toll free or at any phone number listed below.

Calgary Contact Information:

Mail To:
240 - 70 Shawville Boulevard SE Suite 1460
Calgary, AB Canada T2Y 2Z3
+1.403.992.3528 Telephone
+1.877.497.3528 Toll Free

Edmonton Contact Information:

Mail To:
3428 99 Street NW
Edmonton, AB Canada T6E 5X5
+1.780.424.7663 Telephone
+1.877.497.3528 Toll Free

Vancouver Contact Information:

Mail to:
1489 Marine Drive
West Vancouver, BC Canada V7T 1B8
+1.604.261.7663 Telephone
+1.877.497.3528 Toll Free

+1.877.497.3528  |  |
Blog Post Topics;  Flat Roof Snow Removal, Commercial Roof Snow Removal, Roof Snow and Ice Removal Safety, Commercial Roof Snow and Ice Removal Expertise, Flat Roof and Commercial Roof Drainage, Commercial Roof Snow Weight Loads