Flat Roof Drainage System Design

Improper gutter drainage can cause erosion of soils and foundation issues.

Flat roof drainage system design.

Most draining systems on flat roofs have a poor design or are not correctly installed. Unlike other roofing types that are slanted or sloped to allow water to drain automatically flat roofs need a built in drainage system to help remove moisture and debris. It is important for architects plumbing engineers and civil engineers to work together to design a system that will properly drain rainwater from a building and site. To design a sloped or flat roof drainage system we need to know the anticipated maximum rainfall rate and the flat or projected roof area.

Each of these systems has its own pros and cons. There are roof coating products available if there isn t enough slant or slope to accomplish this. This manual provides comprehensive guidance on how roof drainage systems for buildings should be designed using information given in european standard 12056 3 2000 gravity drainage systems inside buildings part 3. Poor drainage can lead to serious issues with flat roofing from leaks to structural damage.

Screw a drain cover over the end of the tubing as it approaches daylight to keep critters out. Of course the best designed flat roof has the correct amount of pitch to drain the water off naturally. There are three types of drain systems on a flat roof. What is the general area of a flat 1 4 1 0 slope single ply roof for each roof drain ratio for the number of roof drains roof area.

The most efficient drain for flat roofs. The one challenge with flat roofing is ensuring proper drainage. Your building and location can help determine which drain will fit your roof needs. Roof drainage layout and calculation.

This is a video showing a drain inside a basin. Buildup of rainwater on a roof can cause structural damage and leaks. 6 24 2014 david howard aia said. Where the tube passes by the downspout from the gutter we installed a y fitting and drained the roof water from the gutter system directly into the main drainage line.

It is very critical to position drains for maximum effect. Check this page out about scuppers. To design a sloped or flat roof drainage system we need to know several things. The maximum rainfall rate anticipated in the area where the building is located the flow in liters per minute per square meter for some x number of minutes.

Flat roof drains on commercial flat roofs. There are three types of drain systems commonly used on flat roofs. This is the ultimate roof drain design. Flat roof drains are the most critical components of any commercial roof.

Flat roof drain types. 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. So often we find that inner drains are high on the roof causing water to pool around them.