• Flat roofs offer ample space for greenery and environmental consciousness.on roof image by cherry from Fotolia.com
  
  A flat roof is horizontal or nearly horizontal, with only slight inclination to allow for water runoff. A continuous membrane is the most common method of applying a flat roof. This will ensure the most protection from the elements. In the Modern period of architecture, a flat roof was seen as an ideal living space, such as a rooftop terrace. Now, green roofs take advantage of the flat surface for planting.
  
  

Built Up Roofing (BUR)

• This is the most common flat roof material. This system is comprised of alternating layers of asphalt and reinforcing materials, which are usually glass fiber or mineral-surfaced sheets. The asphalt is heated and applied hot, mopped onto the entire roof surface to form a continuous membrane. The surfacing material is gravel, which continues the waterproofing of the layers below.
  
  

Thermoset Single-ply Membranes

• EPDM is the most common thermoset membrane. Thermoset implies it permanently sets once heated. EPDM stands for ethylene propylene diene monomer, a synthetic rubber roofing membrane. According to Conestoga Roofing, which specializes in industrial and commercial roofing, this method is the simplest to install, least expensive and most energy-efficient and environmentally conscious. It is the material most used to prevent leaks, has a long lifespan of 15 to 25 years and stands up well to harsh weather. It can be applied using only water-based adhesives.
  
  

Thermoplastic Single-ply Membranes

• These membranes can be heated and cooled repeatedly for maintenance and repositioning, making them more flexible. TPO, or thermoplastic olefin, is flame-retardant, absorbs UV rays and is constructed of polypropylene and polyester. PVC sheets come in a variety of colors and adapt to each roof specifically by conforming to its shape.
  
  

Metal Roofing

• Flat metal roofs are expensive, but effective in terms of protecting your home from the elements and any interior accidents, such as fires. They can be constructed of copper or tin, and are soldered together in interlocking panels to form a continuous membrane. They are flame-retardant and have a distinctive aesthetic appeal as well.