What is a flat roof and should I consider it for my house?
The word "flat" is defined as a horizontally even surface, and so the definition of a "flat roof" is quite similar . Chosen as a staple roof type in many countries around the world, a flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is known as its pitch, and flat roofs have a pitch of up to 10°. Derived from Egyptian, Persian and Arabian architectural styles, flat roofs are an ancient form of roofing that was initially used in arid climates and allow the roof space to be used as a living space or a living roof. Also known as "low-slope" roofs, flat roofs are commonly found on commercial buildings throughout the world. In warmer climates where rainfall and freezing is scarce, flat roofs are built of masonry or concrete, which is good at keeping out heat and affordable in places where timber is not readily available. Flat roofs are not suitable where the roof could become saturated by rain and leak, or where water soaked into the brickwork could freeze and lead to the mortar breaking up. Flat roofs are common here in America because of their simple design, and it's a good roofing option to consider for your home.
What are the different types of flat roof material?
Because the structure of a flat roof is simple, many materials can be used to build it. Here are some of them.
PVC: This is short for Polyvinyl Chloride membrane roofing and popularly known as vinyl roofing. Vinyl is derived from fossil fuel and salt. Petroleum or natural gas is processed to make ethylene, and salt is subjected to electrolysis to separate the natural element chlorine. Thermoplastic is heat-welded seams form a permanent, watertight bond that is stronger than the membrane itself. PVC resin is modified with plasticizers and UV stabilizers, and reinforced with fiberglass non-woven mats or polyester woven scrims, for use as a flexible roofing membrane.
TPO: Short for Thermoplastic Polyolefin single-ply roofing. This roofing material can be fully adhered, mechanically fastened, or ballasted. TPO seam strengths are reported to be three to four times higher than EPDM roofing systems. This is a popular choice for "Green" building as there are no plasticizers added and TPO does not degrade under UV radiation. It is available in white, grey, and black. Using white roof material helps reduce the "heat island effect" and solar heat gain in the building.
Asphalt: Asphalt is a byproduct of the oil industry, and comprises of four types of roofing asphalt. Each of the four type is created by heating and blowing with oxygen. The longer the process, the higher the melt-point of the asphalt. The first type of asphalt has characteristics closest to coal tar and can only be used on dead level surfaces. The second type is considered flat and can be applied to surfaces up to 1/4 in 12 slopes. The third type is considered to be "steep" asphalt but is limited to slopes up to 2 in 12, and the fourth type of asphalt is "special steep". The drawback is that the longer it is processed, the shorter the life.
EPDM: Short for Ethylene propylene diene monomer rubber, EPDM is a synthetic rubber most commonly used in single-ply roofing because it is readily available and simple to apply. Seaming and detailing has evolved over the years and is fast, simple and reliable with many membranes including factory applied tape, resulting in a faster installation. The addition of these tapes has reduced labour by as much as 75%. EPDM is a low cost membrane, but when properly applied in appropriate places, its warranted life span has reached 30 years and its expected lifespan has reached 50 years.
How much does a flat roof cost?
There are many factors that affect the overall price of your flat roof, such as roof size, your area, material used and the complexity of the installation. The average cost of a flat roof, however, is $5-10 USD per square foot. To get a rounded off figure of the entire roof costs, browse the net for roof calculators so you can work out how much the entire cost will be.
How to find a reliable roofing company?
A roof is a big deal, and you want one that's installed properly so it can last you for many years to come. So when it comes to finding a reliable roofing company, do your homework and get the assistance of an architect for the best advice. A legitimate roofing company should provide you with local references and roofing testimonials, business license, roofing credentials, workers compensation insurance, general liability insurance and written manufacturer warranties.