Roof Drainage Design Guide

The sizing of the roof drainage system must consider all components.

Roof drainage design guide. Type of roof construction 2. Rainfall intensity roof catchment area gutter size capacity gutter fall gutter outlets sumps rain heads nozzles downpipe size quantity and placement overflow consideration material. Inspect the roof surface and roof drains on a regular schedule to find and clear away any debris clogging the drains. Desired rate of drainage 6.

Design assistance services are offered as a courtesy to the roofing design professional and contractors to ensure the project s success. Pleasing dome shape with a low profile and adequate free drainage area corrosion resisting dome material effective debris protection overflow drainage to allow drainage during debris build up gravel stop positive flashing clamp seepage control channels. Slope of the roof. To select the proper roof drain the following information must be known.

Roof load requirement 7. Calculate total roof area. The greater the slope the less water build up and thus roof load. In either case the discharge shall be located so that it is readily visible by building occupants.

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. First and foremost be sure to comply with all local plumbing codes. Structural design of the roof and roof load. Maximum pipe flow.

In the design and detailing of a roof drainage system consideration must be given to a range of factors such as. Safety load requirement 8. Properly designed roof drain must have the following features. Secondary drainage shall be provided through the use of sidewall scuppers or internal roof drains.

2 3 4 5 6 and 8 in. From there consider the following. Ipc provides four steps to size the roof drains on a building. Determine 100 year 1 hour rainfall rate used for location of building.

The location and degree to which. Roofs inevitably serve as temporary rainwater reservoirs. Location of drains 5. Inspect the current roof drain s and the drain line through the building for leaks and assure that the materials are.

Determine leader or pipe size. Calculate the total roof area by multiplying its length by width. When selecting a roof drain note. Step by step instructions step 1.

The rain storm the flow of rainwater on the roof surface the ability of the roof drain to move the water from the roof to the piping the vertical piping the horizontal piping and the connection to the point of discharge. 2 3 4 5 6. Size vertical storm drainage piping. Size horizontal storm drainage piping.