Flat roofs, also known as low slope roofing systems, are not entirely flat. They may look horizontal or nearly horizontal, but they usually have a slight slope of about 10 degrees to allow water to drain off.
Flat roofs have been around for centuries and the old technology of using asphalt compounds to deflect water was being used until thirty years ago. New technologies minimize the use of asphalt where possible and also provide insulation properties, as well as waterproofing.
Benefits of flat roofs are that they are more accessible making it easier to inspect, maintain and clean. With a properly maintained flat roof, you can extend the longevity of your entire roofing system.
Flat roofs can potentially increase the insulation value of your home. Foam roofing systems, for example, have an inherent insulating value that can reduce your cooling costs and help the environment by reducing the heat reflected off your roof.