As more modern designs become popular in home construction, the residential flat roof is gaining a following among some homeowners. Even traditional homes may have some sections of flat roofing incorporated into their design. And a flat roof is not truly flat; they are always slightly sloped – about one-eighth of an inch per foot or rise, to ensure that water does not gather and stand on the surface.
Despite the obvious weather-resisting advantages of the sloped roof, most experts agree that a properly built flat roof with good flashing can stand up as well as a traditional roof. With improvements in flat roofing materials over the decades, some now carry warranties of up to 20 years, though 15-year warranties are more common.