Roof Rainwater Drainage Design

Approved document h makes basic provisions for adequate disposal of rainwater from roofs and paved areas minimising the risk of blockages or leakage and ensuring access is provided for maintenance.

Roof rainwater drainage design.

The number and position of downpipes. Box gutter with rain water head at end of box gutter. You can view information on the design of roof drainage systems in the brochure for your state. The above sizing data is offered as a guide only.

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 flow characteristics of the gutter system. Rainwater drainage is covered by building regulations part h3. Last updated 23 jan 2019.

Take the roof s total square footage and divide by the total square footage handled by one drain. Lysaght rainwater solutions nsw guide pdf 2 8 mb. Jun 28 2020 explore casdesigns s board roof drainage on pinterest. Determining the exact roof area and the number of drains is precise work so it requires coordination.

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. Buildup of rainwater on a roof can cause structural damage and leaks. Lysaght rainwater solutions vic tas guide pdf 1 6 mb. To prevent erosion make a rock bed around the end of the tube.

You also must include half of the area of any vertical walls that may divert rain to the roof. The next step is to determine each roof area that will be served by a separate leader drain pipe scupper or downspout. Screw a drain cover over the end of the tubing as it approaches daylight to keep critters out. To assess the suitability of a gutter system to drain the roof of a building the following factors need to be taken into consideration.

Improper gutter drainage can cause erosion of soils and foundation issues. 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. As we will see in steps 3 4 the size of the roof drain lines is dependent on the square feet of the roof area being served by each roof drain. See more ideas about rain water collection rain water collection system roof.

Simplified suitable for flattish roofs with little or no vertical faces or steep roofs draining to one side of box gutter only or any roof if you are in a hurry and make the necessary allowances for all catchments. Rainwater calculations are carried out in accordance with bs en 12056 3 2000 and. This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table. The result is the number of drains needed.

Lysaght rainwater solutions qld guide pdf 2 2 mb. Sizing a roof water drain. For further rainwater design advice view our rainwater design and installation guide. Last updated 26 aug 2016.