Roof Drain Layout

Install a drain at most 50 ft.

Roof drain layout.

There are three types of drain systems on a flat roof. The next step is to determine each roof area that will be served by a separate leader drain pipe scupper or downspout. It is very critical to position drains for maximum effect. Most draining systems on flat roofs have a poor design or are not correctly installed.

Roof drains zurn plumbing products groupspecification drainage operation 1801 pittsburgh avenue erie pa 16502 phone 814 455 0921 fax. Following are some basic design guidelines to consider as part of your project courtesy of jay r. Factors which affect proper roof drainage are deck slope drain size and placement of drains. The roof is sloped towards the drain through either tapered insulation or through joist modifications below the roofline.

From a roof edge. The full flow capacity of a drain is not realized until the water reaches approximately 2 5 above the inlet in a four inch drain and 3 5 in a six inch drain. This form of roof drainage is preferred if a clean exterior appearance is desired. Limit roof area to 25 000 sq.

Sizing a roof water drain the first step in sizing a roof drain is to calculate the surface area of the roof that the drains will be covering as well as the average hourly rainfall rate at the building location. The sizing of roof drains must be large enough to quickly carry away all water entering the roof drains. General roof drain system guidelines. From the edge of a valley.

These will drain to somewhere near the center of the roof and down through the building to underground storm mains or a detention pond.