What Angle Should You Put Up for a Flat Roof?

Flat Roofs

• Any roof that looks flat may be referred to as a flat roof, regardless of the actual slope of the roof. Flat roof slopes vary in angle from very minimal, less than 1 percent slope, to up to 10 percent, which still generally appears flat from the ground. Roofs should never be installed completely flat on a building surface because debris and water can accumulate, leading to roofing problems. Even if you intend to keep up a dedicated maintenance schedule to clear debris from a roof, it may pile up quickly during storms.

Danger of No Slope

• The main danger of having a perfectly flat roof with no slope is the possibility of the roof collapsing. When water or heavy debris accumulates on the roof, the roof may be unable to support the weight and collapse. Anyone or anything inside may be crushed or damaged by falling debris. Even if the roof does not collapse, supporting heavy weights for a prolonged period of time can weaken the structure of the roof, making it more prone to collapse in the future.

Flat Roof Uses

• In most locations, flat roofs do not provide enough protection for residential buildings or structures. In areas of the country with little rain or snow, however, flat roofs do generally serve as a viable option. Some benefits of a flat roof include the ability to use the roof as outdoor living space in place of a patio or a deck and the ability to install solar panels without having to work around the slope of the roof to angle them toward the sun.

Flat Roof Angle

• A flat roof doesn’t require much of a slope in order to allow water and debris to slide off. This Old House and Southern States Roofing recommend a slope of at least 1/8- to 1/4-inch per foot, which is the equivalent of less than a 1-degree angle. The more angled the slope of a flat roof is, though, the more easily potential hazards slide off, so the more angle that you can give to a slope, the safer the roof will be.