6 things to know to properly maintain your flat roof

In Canada, many buildings are equipped with flat rooftops. This type of roofing is very practical and often less expensive than a slanted roof. However, since we don’t see their surface, we’re more likely to forget to check their current condition.  

Flat roofs can be covered using different materials: bilayer elastomer membrane, multiple-layer asphalt (Built-up roof), TPO membrane (thermoplastic polyolefin) and EPDM membrane (Ethylene Propylene Diene Terpolymer). Most of the advice that is shared in this article will apply to every one of these different materials but if a piece of information only refers to one case, it will be specified.

Why flat roof maintenance is important

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Taking proper care of your roof will greatly increase its durability. For example: when multi-layer asphalt roofs are not well maintained, their lifespan lasts approximately 15 years. However, if well cared for, they can last from 20 to 25 years.

1- Rooftop inspection: how often and when?

A flat roof must be inspected twice a year. The first visit of the year should be done in the spring after the last traces of snow have disappeared. The second should take place in the fall, once the trees have lost all their leaves.

2- What to look for during a flat roof inspection

- Pay attention to the surface’s uniformity. Normally, if the roof is in good shape, there shouldn’t be any parts that are detaching or sections that are warped.

- However, do not be concerned at the sight of asphalt bubbles. As long as they are intact, you should only protect them from getting hit with direct sunlight, using a layer of gravel. If you find bubbles that are popped, fill them in using liquid asphalt and add a layer of gravel on top.

- If applicable, check around the chimney. For a masonry chimney, inspect the joints between bricks and, if necessary, fix them.

- If you notice that after a few days of sunny weather, water is still accumulating and forming a puddle on the flat roof, this could indicate a problem with the drain.

3- Improving the flat roof’s waterproofness

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One of the main problems with flat roofs is waterproofness. Applying a coat of protective paint can be a great option to fix this situation.  Since it helps block sun rays, it will also act to protect the asphalt.

4- Cleaning the flat roof’s surface

Debris accumulation is a situation that can quickly turn into a major problem. Therefore, it has to be taken care of quickly and regularly. During the inspection process, set aside a bit of time to clean the roof and the eavestroughs, removing any branches, leaves, moss, rocks and any other element which could potentially cause damage. 

This advice is especially important when talking about flat roofs that are covered with a layer of gravel, as the wind tends to displace the small rocks.

Pay special attention to the areas near any air vents and around the drain, to see if the latter could become blocked. Having a blocked drain is one of the worst possible situations that can happen with a flat roof. Water will accumulate on the surface and will pass through the slightest crack, in addition to creating extra weight. This could cause overflow on the building’s exterior walls.

For rooftops that are covered in gravel or granules, sweeping and putting things back into place with a broom could make a huge difference. Always make sure that the rocks are well spread out on the surface, as they serve to protect the rooftop.

5- Hiring a roofer

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During the bi-annual inspections, if you notice worrying signs or irregularities, bring in a company that is specialized in rooftops to take a look at things. Rooftop reparations should never be taken lightly as the house’s structural integrity depends on it.  One tiny leak can cause important damages.

Furthermore, if your roof is still under warranty, if you try to fix things yourself, you might not benefit from said warranty. Sometimes, it’s also worth it to hire a specialized plumber to clean the pipes and drains. This task should be done every 5 years (even more frequently if your house is surrounded by trees).

6- Renovating a flat roof

You’ve noticed that it’s time to redo your roof? Take a look at all the options that are available to you. Bilayer elastomer membrane and multiple-layer asphalt (Built-up roof) are less expensive but they require a higher maintenance level. EPDM and TPO surfaces are more costly but they last longer and are more environmentally friendly

Please note: Don’t forget to take extra precautions when climbing up on a rooftop, especially if you have to use a ladder.

Always follow these 4 safety rules as suggested by the CNESST:

- Rest the ladder on a solid surface;

- Climb with your hands-free;

- The ladder must surpass the top support section by at least 900 mm (35 inches)

- Attach the ladder properly