MAKE SURE YOU’RE BEING COVERED BY A SOLID FLAT ROOF
Decide what works best for you based on climate, available materials and budget
Contemporary home design seems to be favouring a lot of flat roofs lately. I’ve seen them popping up all over some urban neighbourhoods. Though they’re trending now, if you’re getting a new flat roof, or replacing an old one, there are some things to keep in mind before you call the roofer.
Even if most of your home is covered by a pitched roof, there may still be some flat sections to account for (my garage has a green flat roof jutting out from the structure to create some shade).
FLAT ROOFING MATERIALS
Just like with a pitched roof, there’s not one perfect material for all flat roofs. Take a look at your options and decide what works best for you based on your climate, material availability and budget.
For most homeowners, price will be a major deciding factor, but make sure you’re making an informed decision before you decide. Paying more for a higherquality roof may end up being a cost savings in the future if it means you don’t have to spend money to keep fixing it.
If you have a flat roof in need of replacing, here are some options to get your search started:
SINGLE-LAYER MEMBRANE
You can break down singlelayer membrane roofs into two categories: thermosets (compounded from synthetic rubbers) and thermoplastics (made from plastic-based materials).
Applied as a single layer, they can be loose laid and held down with rock ballast to provide stability or completely adhered to the roof deck.
Both materials provide resistance to UV rays and are flexible, meaning they can expand and contract with the roof deck as the weather shifts.
MODIFIED BITUMEN
Durable and weather resistant, modified bitumen roofs provide better protection than a built-up roof. Applied by heat welding or hot-mopped, they offer resistance against wind. What’s also great about this material is that it reflects the sun’s UV rays instead of absorbing the heat into your home.
BUILT-UP ROOFS
A more cost-effective option, a built-up roof is the old-school material using hot tar or asphalt that is layered over the top of the structure and is usually covered in crushed stone to protect the built-up material from the weather.
A built-up roof will be heavier than most other materials, so installation may be delayed because you need to reinforce the roof to be able to handle the extra load.
WHERE DOES WATER GO?
First of all, flat doesn’t mean your roof is (nor should it be) perfectly level. It needs to be designed to handle the water. You never want water to just sit and accumulate on your roof. It has to go somewhere, and if it doesn’t run away from the house, it’s going to eventually run inside.
With a low-pitched roof, you can have eavestroughs collect the water as it runs down your roof, and safely expel it away from your home. You can also have an interior drain installed, which places a drain in the centre of your roof, connecting to pipes that drain water down through your roof. This is a more expensive option, and if you take good care of your eavestrough, keeping them clear of debris, you should be able to use gutters without many issues.
WHAT ABOUT THE SNOW?
There may be some misconceptions out there when it comes to how a flat roof can handle the snow — and that’s definitely a big concern for a lot of Canadians!
Local code is written to include minimum guidelines to handle any intended loads the roof is meant to hold.
That accounts for its materials, membrane, insulation and decking, as well as snow and rainfall, and even for equipment, such as an air conditioner.
If we’re hit with a big snowfall this winter, and you’re concerned about the added weight, keep a look out for doors on your top floor that stick, or pop open; this could indicate the extra weight is distorting the frames.
If the added weight is a concern, you could shovel some of the extra snow off your roof. The goal isn’t to clear it completely, but to lessen the load on the roof, especially if it’s wet, heavy snow.
This isn’t a job I’d recommend you do yourself. Bring in a professional with the right tools who will do the job safely.
If you insist on doing it on your own, take every safety precaution. Even in the best of conditions, climbing on your roof is a dangerous job.
Don’t pitch a fit over your roof. If you give it the proper maintenance, choose the right material for your climate and make sure it’s installed correctly (and comes with a good warranty), your roof will continue to stand tall.