Flat roofs on a residential home create a unique challenge. First, flat roof knowledge and technology are typical in the commercial roofing industry. Many residential contractors do not posses either the experience or knowledge to properly install a flat roof. Second, many of these residential contractors will use 90# rolled roofing which is cheap and easy to install as a solution. The problem with 90# rolled roofing is that, in Weathercraft’s experience, it will typically only last four to six years in the Midwest before it disintegrates.
Weathercraft defines a flat roof as any roof that is 2-inch in 12-inch slope or flatter. Depending on how flat the slope is and the desire of the homeowner will often determine which systems best suits the situation.
If the slope is around 2/12 and the roof is visible from either a higher story window from the house or from the front of a home, using a moisture-guard underlayment and matching shingles — or whatever roof system is being used — can be used.
Once a 1/12 slope or flatter is reached, a commercial flat-roof system should be used. The most economical system is to install a mechanically fastened modified bitumen system, with a special underlayment, a specific edge, and slope tie-in details. This system typically lasts as long as a sloped asphalt shingle system would. Other options include a BUR system or a single-ply system.
Because of Weathercraft’s long experience with commercial roofing, we are uniquely suited to solve residential flat roofing problems. We have been installing residential flat roofing since 1976.