Flat roofs are a type of covering for buildings. They are not completely flat but generally incorporate a slight slope that aids in water drainage. Flat roofs are gaining in popularity because technology has eliminated previous disadvantages that have long been associated with them.
Flat roofs are generally found on historically styled modern buildings. They become a part of the architecture, used to reflect the horizontal lines of natural landscapes. Flat roofs are also used over sheds, porches and balconies of old and modern buildings. They are popular roofing options in the Middle East and American Southwest where water drainage isn't a huge concern.
The Built-up Roof, or BUR, is a traditional form of flat roof. It is built by layering tar, gravel and a waterproof membrane such as fiberglass or tar paper. Modified bitumen flat roofs are single-ply rolled roofs. They are built by heating the adhesive as the material is rolled onto the roof or by using the peel and stick variety. Rubber membrane flat roofs are glued, anchored or ballasted into place. They are designed to resist sun damage.
Flat roofs are characterized by their horizontal or nearly horizontal slope. Many different materials are used to cover them. Traditional flat roofs used a tar and gravel covering to prevent water penetration. Today, continuous membrane coverings are used for their superior leak prevention and resistance to water pooling. Sealed metal, decks, paving stones and even topsoil and grasses are also used to cover flat roofs.
Flat roofs are more economical and efficient than other roof shapes because all the space above and below the roof can be utilized. They supply space for outdoor living or recreational space such as roof gardens or decks. Flat roofs are easier to inspect than other roofs and are built to last. They can survive up to 25 years with proper maintenance.
When flat roofs are coated, they present another benefit. They are able to reflect up to 90% of heat from the sun. These coated flat roofs are known as "cool roofs" and can save money on air conditioning the home.
In tropical areas homes with flat roofs can become extremely hot and may require specialized coating to control the temperature. They also require more maintenance than traditional sloping roofs. Pooled water must be removed and not allowed to stand. Leaks are a common occurrence with flat roofs so extra care must be taken to prevent them. They are very sensitive to traffic as leaks can be caused by the slightest fissure. When using flat roofs as living space the membrane must be protected from cracks and punctures.