Modern flat roofing systems are manufactured in membrane form which can be welded or fused together at seams.  Fully welded or fused membranes can last up to 20 years or more and do not require the maintenance of roof cement and coatings.  Granulated surfaces can match shingle colors where flat roofs are visible.  White roofs are available for heat reflection and temperature control.  PVC "walkable" roof surfaces are textured for balcony roof areas.  Walkable roof surfaces are tough enough for furniture, cool enough for bare feet and come in many appeasing colors.