Unlike a shingle roof a flat roof is not much to look at, but it serves a critical purpose; to shed water from your home. There are some things every homeowner should know before receiving proposals from a roofing contractor.
Just like a shingle roof system a flat roof is a collection of individual parts working together as one.
Before any roof is installed there must be a deck to install it to. A deck is usually made up of plywood, deck boards, corrugated steel, or concrete. Why is this important to know? If you have a wooden deck and have had extensive leak problems it may be damaged and need to be replaced. A steel or concrete deck is less prone to this kind of water damage, they can also hold more weight therefore more layers of material. Ask your contractor what shape the deck is in flat roofs toronto.
What about drainage? A flat roof isn’t really flat at all. A better word is low-slope roof. Because of this low-slope, special materials must be used rather that traditional shingles. This low-slope is meant to allow water to shed to drainage areas. The slope can be designed in numerous ways. It can slope to one side. It could have a high-point then slope in two directions. They can even have a low-point in the center. Each design is meant to funnel water to drainage areas.
Scupper Box/Eave Box – This is a built in drainage area at the wall of a roof. Water funnels inside this box to a downspout that runs down a wall.
Gutters – Normal gutters can be used, a proper slope is critical
Yankee Gutters – A gutter system that is built into the existing cornice structure, not easily visible from the ground, not used in modern buildings
Inline Drains – An inline drain is built into the building, usually it is constructed with a low spot in the center where the water will flow into a drain
Each of these drainage systems should be inspected regularly for blockage. Your contractor should detail what system is being used.
Most flat roofs have walls around them. They are called parapet walls. Originally designed for defending buildings, today they are mainly used to prevent the spread of fires. Either way your contractor should mention how they will waterproof them in his/her proposal.
Modified Bitumen – This is most common type. It is a single ply material. Modified Bitumen comes in a limited palette of colors. It also comes in two surfaces: smooth and granulated. A granulated surface will reflect heat better than smooth. The cost of modified bitumen can be considered middle of the road. We always use Certainteed Flintastic STA Plus which is high quality flat roofing product.
EPDM – A type of material often referred to as rubber. This material resembles an inner tube and is lightweight and durable. It is mechanically fastened, ballasted with stone, or glued. Pros include its light weight, durability to scuffs and tears, and leaks are easily patched. The cost is higher than Modified Bitumen, it absorbs heat, and is vulnerable to punctures.
There you have it. Now you can wow your contractor with your knowledge. In all seriousness, we see to many of these roofs that are installed improperly. Check your proposal. The more details the better.