Commercial, Mixed-Use and Strata Roof Maintenance in Vancouver, B.C.

8 Common Flat Roof Issues, To Look Out For | Leak-stop Canada

8 Common Flat Roof Issues, To Look Out For

In my 20 years of roofing, I have often observed property owners neglecting the maintenance of flat roofs issues. Flat roofs, like any other roofing system, require regular care.

If  flat roof issues are not maintained like punctures, weathering, foot traffic, moisture, blistering, etc. can pop up.

However, to avoid these flat roof issues, one first needs to understand the cause of these issues. And then find suitable measures to deal with them. In this article, I have compiled some common but mostly overlooked flat roof issues and their causes. For you to understand and be able to look out for.

Common Flat Roof issues | leaks on flat roofs:

Foot Traffic by Unauthorized People.

When it comes to a flat roof, be it a residential, commercial or industrial construction. There is HVAC equipment, ventilation, satellite dishes, electrical boxes, water tanks, and other objects on it.

Given the fact that all this equipment has to be accessed regularly, foot traffic is unavoidable.

When people walk on a flat roof every day, it results in quick wear and tear of the roofing system. If this continues for years, it takes a serious toll on the roof.

Leaks are only one of the problems caused by excessive foot traffic on a flat roof. If the number of people walking on the roof daily is not monitored. You may lose a few years of your roof’s lifespan and won’t be able to make the most out of your roofing investment.

Punctures. (Flat Roof Issues)

Speaking of the HVAC equipment, ventilation, satellite dishes, electrical boxes, water tanks, and other objects fixed on the roof. Punctures are bound to happen, as all these objects are drilled into the roof.

When these holes are left unsealed and flashings are poorly installed. Water is bound to enter the inner layers of the roofing system, through these punctures. Making the roofing system susceptible to water damage.

Even if the damage is not apparent, it can’t be immediately spotted. It could still lead to catastrophic results if not addressed early on.


Flat roofs just like any other roofing system are subjected to weathering. The heat, rain and the cold winter, affect this roofing system too.

Below are some problems caused due to weathering of a flat roof.

Thermal movement.

During summer the temperature constantly keeps changing. The heat causes the flat roof to constantly expand and contract.

This continuous motion leads to fine cracks in the roof. Waterproofing materials like single-ply PVC are resistant to such damage. However, roofs made up of felt are more susceptible to thermal movements.

Moisture & Blistering.

Flat roofs are prone to water pooling. The lack of slopes means water cannot run off as easily as it could on a sloped roof.

If this accumulated water is not removed on time, penetrates through the cracks and holes in the flat roofing system. When this penetrated water heats up, it turns to vapour and tries to escape the flat roof surface. This causes blisters on the roof.

If the roofing system is open to the interior of the building, this vaporized water condenses and shows up in the form of leaks.

Moisture also causes mold and rust in a flat metal roofing system.

Metal Flashing: (Flat roof Issues)

Metal Flashings are metal linings used to create a watertight seal around penetrations, edges, window openings, ventilation pipes, grooves and other roof obstacles to prevent water damage.

As mentioned above, if these flashings are now installed accurately, they may direct the water into your roof, through the joints rather than diverting it away.

The edges are extremely vulnerable to water, the flashings act as a quality water barrier. They protect the inner layers of a flat roofing system from moisture, even if the roof is prone to water ponding.

If these flashings are not cared for or reinstalled whenever necessary it may cause a chain of roofing issues.

New Units Placements/Additions by Unqualified Trades. (Flat Roof Issues)

It’s always tricky to add a new unit to your flat roofing system. Especially when it comes to commercial or industrial roofs. A piece of new equipment, be it an HVAC unit, a dish or an electric box, need to be placed properly, without damaging the previously placed units and the roof.

Here is where an experienced roofer is needed. Unqualified or inexperienced roofers can make mistakes and jeopardize your roofing system, resulting in thousands of dollars of repairs.

Especially, the HVAC rooftop units which seem to be in plenty on flat roofs, need some calculations before installation. This includes calculating where the load the unit will place on the roof and determining the best location for the rooftop unit. The heaviest parts of these units need to be placed on a beam to avoid sagging and tearing.

An expert roofer can handle all these aspects without compromising any part of your roofing system in the process.


Whether your flat roof is a new installation or even if it’s been part of the construction for several years. Regular inspection and maintenance are essential. However, it is also necessary for property owners to keep an eye on flat roof issues. And if you spot a problem, you will need a reliable roofing contractor.

LeakStop is a one-stop destination to meet your roofing-related requirements. We offer roof repair, replacement, maintenance and inspection services all over GVRD (Greater Vancouver Regional District).

We offer a free inspection to first-time clients. Connect with us TODAY at 1 866 777 0084 for immediate assistance!

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