A flat roof presents the classic mix of challenge and opportunity. If it’s not sealed properly, it can be a constant source of leaks. But treat it right and it can offer an unparalleled place to relax.
That applies whether it’s a boathouse with a rooftop patio, a second-storey deck, or even a balcony with living space beneath.
The key to making the most of the space is to choose the right product to seal it. And that’s where it gets tricky.
Mike Vettese of GBS Contracting Services says there are six basic systems of flat roofing for residential and commercial projects: PVC single-ply, EPDM single-ply, TPO single-ply, modified bitumen two-ply, BUR tar and gravel four-ply, and spray-on coating. Most have variations and different brand names to consider as well.
Every one of them has different uses, he says, although some have decided downsides. Gravel is high maintenance, for example, while spray-on coating is best treated as a short-term fix. “When working with residential installations, I usually recommend the modified bitumen two-ply system or the EPDM single-ply system.”
The modified bitumen system features fabricated layers of asphalt, which are modified using rubber or plastic ingredients to increase flexibility. The 25-year roofing system also includes a reinforcing agent for added strength and stability. Bitumen displays a thermoplastic quality when softened by heat, so it remains intact rather than cracking. And new high-performance roofing systems can be quickly installed, and they’re easy to maintain and cost efficient.
The EPDM single-ply membrane system comes as flexible sheets of compounded synthetic materials that are manufactured in a factory to strict quality control requirements. Available in black or white membranes, they provide strength, flexibility, and durability.
“Every job has its own nuances we need to determine and work with,” says Mike. “It’s important to understand all the benefits and drawbacks of each material, so we can provide the best advice to help you make an informed decision for your home or cottage.”
The gold standard, Mike says, is the Dec-Tec PVC membrane system. When installed professionally, it should last 25 to 30 years.
It is the only membrane that is certified for roofing, and GBS has used this application for a range of balconies and upper-level decks throughout Muskoka. It’s the most expensive membrane, but it’s worth the cost, says Mike.
“This is the membrane that should also be on all boathouse rooftops,” he says. “Dec-Tec does not require planks or a deck above the membrane; when heat welded at 2,000-degrees Celsius on top of good plywood to create a seamless seal, it becomes the deck.”
Dec-Tec has an excellent reputation for safety and durability. The product is tested to withstand four-season weather conditions in Canada. It’s slip-resistant, waterproof, and fire-resistant – making it ideal for high-traffic areas.
As well, the membrane comes in a large variety of colour and design options – from classic Muskoka looks that mimic granite, cedar planks or redwood, to modern options like ivory and oak.
“It’s also very low-maintenance and easy to clean,” says Mike. “Really, it’s a perfect fit for your outdoor entertaining spaces.”
Of course, as with any project, proper installation is essential to having a high-performance, long-lasting roof. Regardless of whether the structure is insulated or not, heated or not, a quality roof will keep the building beneath it dry. “When the roof is designed well, the snow will melt and the water run down the drains, preventing a build-up of snow and ice creating a heavy load and eventually causing leaks and damage,” Mike explains.
A flat roof can be more cost efficient to build than most sloped roofs with trusses. And of course, they are popular on boathouses since the roof can act as a lounge for outdoor gatherings and allow a usable space below, without running into height restrictions the way a peaked roof can.
“There are plenty of benefits to putting a flat roof on your boathouse, cottage, or home,” says Mike.
No matter what construction project you are undertaking, be it roofing or something else, make sure to hire certified, insured, and experienced professionals.
GBS Contracting Services has been in business since 1999 and are experts at roofing, siding, and other projects. Their team is fully insured, fully trained, and dedicated to the business. Mike says they happily provide references to their clients. He notes that they often get called back to do additional work because the client is so happy with the first project.
“Our team lives in Muskoka and understands the environmental pressures on the buildings in our communities.”
TEXT CHRIS OCCHIUZZI | PHOTOS ANDREW FEARMAN