Flat Roofs: A Homeowners Guide

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Flats roofs give a home an unusual look that makes a house stand out from the other residences in the neighborhood. If you are looking to purchase a house with a flat roof, it's an excellent idea to know as much about it as possible before coming to any final decision.

This article offers more information about flat roofs.

How They Work

The key point to remember about flat roofs is they are not perfectly flat. If they were then water would not drain from your roof, which would cause damage over time. Flat roofs actually have a pitch or slope, but one that is far less steep than a typical residential roof. For example, Florida building codes require a flat roof with a slope of two percent. This works out to ¼ inch for every 12 inches of the roof. Such a small slope is almost unnoticeable to the eye but is enough to ensure water drains off the roof surface.

Roofing Systems

Flat roofs have different requirements than higher-pitched roofs, so traditional asphalt shingles are not acceptable as a roofing material. Typically, one of two is used for most flat roofs: a membrane system and modified bitumen roofing (MBR).

A membrane system consists of a layer of insulation board covered on top by a membrane, which can be made of various materials. The most common covering material for residential homes is known as ethylene propylene diene monomer (EPDM). Some advantages of EPDM roofing are that it rarely leaks and any necessary repairs are usually rather simple and inexpensive.

MBR roofing has the advantage of being fairly easy to install and not needing a lot of maintenance.

Drainage System

Every roof needs to drain water from its surface and flat roofs are no exception. One system is to have interior drains that carry water away from the foundation. The drains are located in the middle of the roof and carry the water through pipes under the roof. This system is more commonly found in commercial buildings but can be used in homes. Another option for drainage is using scuppers, which are square openings on the roofline that allow water to pass through. Scuppers are cost-effective and rarely get clogged, according to roofing professionals.  

Other flat roofs are drained by gutters, just as you typically see with higher-pitched roofs. 

If you are interested in learning more about flat roofs for residential homes, contact an experienced roofing contractor in your area.