Roof Drainage System Plan

Secondary or emergency roof drainage is required wherever the buildup of water is detrimental to the roof structure.

Roof drainage system plan.

Green roof solutions offers many different drainage layer options depending on system goals regarding water retention. Functioning drainage system for steep slope roofs is to maintain a minimum roof slope. 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. The value of tcdepends upon the size and layout of the roof and the drainage system.

The most critical role of the drainage layer is to provide an adequate flow of water off the roof during and after rainfall. Design assistance services are offered as a courtesy to the roofing design professional and contractors to ensure the project s success. The drainage plane and drainage logic should encompass the entire building enclosure. In the case of a building with gutters tcwill usually be the sum of the time taken for water to flow down the roof and the time taken for it to flow along the gutter to an outlet.

Determine 100 year 1 hour rainfall rate used for location of building select number of roof drains and calculate the roof area sloped to each drain size horizontal storm drainage piping size vertical storm drainage piping. The design of the different drainage layers allows for a portion of the stormwater to be retained above where the water is allowed to flow freely off of the roof. Secondary drainage shall be provided through the use of sidewall scuppers or internal roof drains. The most critical of these issues is the flat roof drainage systems.

The main benefit of inner drains is that the system is hidden from view. Inner roof drains are used on flat roofs and include a low section or channel that collects water and feeds it into a concealed drain that leads to an underground drainage system. Along with the benefits of a flat roof come unique challenges. Your building and location can help determine which drain will fit your roof needs.

Of course the best designed flat roof has the correct amount of pitch to drain the water off naturally. Inner drains are resistant to freezing but can require careful maintenance to prevent problems. To prevent erosion make a rock bed around the end of the tube. Typically a steep slope roof slope is equal to or greater than 3 inches of rise per 12 inches of run 25.

Developing the design criteria for a roof drainage plan that will perform with the roofing system to drain the roof is critical priorto the bid process and roof system installation. Establishing a minimum slope is critical because most steep slope roofing as. Ipc provides four steps to size the roof drains on a building. In either case the discharge shall be located so that it is readily visible by building occupants.