Problems With an Almost Flat Roof

Life Span

• Flat and almost flat roofs have a shorter life span than other types of roofs, according to Michael Stern of the Preservation Alliance for Greater Philadelphia. A flat roof typically features tar paper or poured asphalt that typically lasts 12 years or less. A metal or slate roof might last for a century, while even asphalt shingles last up to 35 years. The design of the flat roof makes it incompatible with the tiles or shingles found on other types of roofs.

Environmental Dangers

• Other types of roofs have a slope that pushes water, snow and ice away from the roof and onto the surrounding ground. As heat rises, the warmer temperatures melt snow and ice. With flatter roofs, the moisture has nowhere to go. As it melts, it cannot slide off the roof, so it settles on different areas of the roof. Even a building with a low pitch can suffer from moisture problems. The water builds up, adding weight to the roof, which can result in a collapse. The roofing materials begin looking weathered or rusted within a few years of use. The moisture can lead to cracks, which create leaks inside the building.

Environmental Problems

• In addition to moisture on the roof, you might face other problems. With ice or snow, a roof risks developing ice dams. The melted snow and ice moves down the slope but freezes when it encounters the colder temperatures. This water creates icicles on the edges of the roof, which weigh down the eaves and low-hanging areas and might cause the roof to collapse. The roofs are susceptible to wind damage because the wind grabs the roof and carries it away, unlike sloped roofs where the shape blocks some wind. An almost flat roof is also at risk of damage from earthquakes, as the flat design cannot absorb the impact of the earthquake.

Other Problems

• Roofs with a partially flat design have higher maintenance costs than other types of roofs because of the potential damage facing the space. The cost rises when you consider the frequent replacement of the materials. The roofs also allow more burglary or theft. A thief can climb onto the roof and gain quick access to the upper floors of the building.