Flat Roof Drainage Design Guide

The result is the number of drains needed.

Flat roof drainage design guide.

Some pipes are too small to handle the volume of the water. Unless otherwise recommended by a geotechnical engineer lacrc. Size vertical storm drainage piping. Along with the benefits of a flat roof come unique challenges.

Take the roof s total square footage and divide by the total square footage handled by one drain. The most critical of these issues is the flat roof drainage systems. Your building and location can help determine which drain will fit your roof needs. Flat roof drain types.

Poor drainage can lead to serious issues with flat roofing from leaks to structural damage. There are three types of drain systems commonly used on flat roofs. Having sufficient drainage on a flat roof is vital. The drainage requirements for flat roofs on buildings present some special problems that we describe and illustrate here.

Determine 100 year 1 hour rainfall rate used for location of building. The flat roof drainage design guide can go up against different style that when nitty gritty right can ooze a cutting edge feel. Ipc provides four steps to size the roof drains on a building. Most flat roofs suffer from poor drain locations or drain levels that are high.

Show down spout and location of discharge to ground surface which shall be at least 5 feet from foundations walls or to an approved drainage system. Size horizontal storm drainage piping. Of course the best designed flat roof has the correct amount of pitch to drain the water off naturally. Drainage devices e g sizes elevations type of material inlet and outlet structures energy dissipators.

It is a requirement of building regulation part h that adequate provision is made for rainwater to be carried from the roof of the building. According to bs 6229 bs 8217 flat roofs should be designed with minimum falls of 1 40 to ensure a finished fall of 1 80 can be achieved allowing for any inaccuracies in the construction. Select number of roof drains and calculate the roof area sloped to each drain. There are roof coating products available if there isn t enough slant or slope to accomplish this.

Main features flat roof drainage design guide first off the flat roof drainage design guide is an extremely basic direct and utilitarian design every single current trademark. Watch for clogs blockage at the roof drain or scupper. When designing a roof it is essential to pay close attention to where the drains are. At page top and at left our photos show a low slope roof surrounded by a parapet.

Keep in mind all flat roofs have a slope of between five and 15 degrees to allow water to flow into drain systems such as eaves drainage holes or outlets. The one challenge with flat roofing is ensuring proper drainage. Or 12 drains required. On many occasions drains are too high and water cannot flow off.