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Commercial Flat Roof Replacement

Aug 25

Flat roofs present unique challenges when it is time to repair or replace them. Shingles, most metals, and tiles are not viable for flat roofs. Although it has been possible, shingles, most metals, and tiles are unsuitable for such roofs. It also doesn't always work well. 


Flat roofs have two options: a built-up roofing system (BUR) or one of the modern membrane techniques. It is challenging to decide which option is more feasible and cost-effective given the price of specific options and the difficulty in removing others. Is it worth replacing or repairing commercial flat roofing toronto ?


We'll give a quick overview of flat roof materials, how they work, and the signs that a roof needs attention. This roof is a whole different animal than a pitched or sloped one. However, the same problems can occur for different reasons.

Built-Up Roof (BUR)

BUR is the oldest method of constructing a flat roof without wood or exposed adobe. 

It is constructed by adding layers of tar/asphalt and fiber (often fiberglass though felt initially). It can be topped with crushed rock, river rock or artificial mulch, lava rocks, or crushed shells. It is usually available in pre-sandwiched asphalt rolls and fiberglass or felt. You can apply it with heat, a chemical activator, or self-adhesion. Heat is the most popular and oldest method.

Membrane Roofs

There are many chemical compositions for membrane roofs. The most common is a polyvinyl chloride base (PVC) or vinyl. However, other synthetics can be used. They are a single sheet of material usually self-adhesive, though some may use an applied cement.


These roofs are often topped with loose gravel or similar material for aesthetic protection. However, some experts advise against it. Although more recent, membrane roofs can last longer and be simpler to install. However, they are more expensive, more challenging to fix, and can be a hassle to put up if you need to replace a roof.


When do you need to repair your flat roof? It's a good idea, first and foremost, to have your flat roof inspected at least once a year. It is possible to catch problems early on, reducing the need for costly repairs and minimizing the risk. Commercial structures are subject to inspections more frequently than is required by law.


However, problems can sometimes be overlooked or arise right after an inspection. This happens all the time. Here are some signs that your roof might be in trouble

Your Roof Is Old

Your roof could be too old if you have BUR. Sometimes it may take less than 50 years. It could take 25 to 100 years for the membrane (the membrane is still not at the point of aging, so that it may be longer). The seals can wear down, and a roof becomes less efficient at its job. This leads to more problems. It's time for a roof replacement if it is past its expected lifespan.

Have You Leaked

Water damage can be severe. Water damage can lead to mold, sheetrock decay, rusted or damaged infrastructure, and electrical fires. Leaks are a sign that your roof is damaged or punctured. You will need to repair it.


Molds can grow and spread quickly, and they can become toxic before you even notice them. Black mold can be a severe problem, especially in commercial locations. It can pose a serious health risk to children, seniors, and the infirm. Even healthy adults can be affected by it.

High Energy Bills

Leaks are not limited to water invasion. As well as compromised seams and decayed insulation, air can escape. This is a way to let the heat out in winter and the air conditioner out in summer. This is why you'll notice a rise in your bills, even if it's not for any apparent reason.

Visible Damage

Inspections should identify visible damage. However, if the problem is recent, it may not be. Flat roof damage can be seen as seams breaking apart, flashing unfinished, or blisters under the sheets. You can usually repair a roof if it isn't too old and the damage is caught quickly.


Tear-Away or Roofing over

Let's not assume that roof replacement is too expensive and that you must repair a damaged roof. There are two types. Tear-away roofs (or tear-off) are when the roof is removed and replaced with a new one.


With many flat roofs, this can be a difficult task. It is difficult to remove the asphalt or adhered membrane layers. Sometimes, it may require reheating to make it malleable. This is the most expensive option for roof replacement, regardless of whether it's flat or sloped.


Another option is to repair any blisters and seal problems, then apply a new layer of the membrane. This is not as reliable as BUR when it comes to the membrane. You can't roof over everything. And you will eventually have to tear it off.

Repair or replace?

What is the extent of the damage, and how old is your roof? You can repair it if it is not beyond its expected lifespan or very close to it. BUR and membrane are more accessible to repair than some styles of sloped roof shingles. This involves removing blisters and reapplying adhesive. Flashing can be easily replaced if you need to open seams.


If the damage appears limited, your roofing professional may suggest repairing it. If it isn't, you can replace it. If you feel the damage is severe and spreading, take the time to replace it.