Roof Rainwater Drainage Design

Sizing a roof water drain.

Roof rainwater drainage design.

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. Calculate drains needed. Improper gutter drainage can cause erosion of soils and foundation issues. Buildup of rainwater on a roof can cause structural damage and leaks.

Lysaght rainwater solutions nsw guide pdf 2 8 mb. 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. For further rainwater design advice view our rainwater design and installation guide. To assess the suitability of a gutter system to drain the roof of a building the following factors need to be taken into consideration.

Determining the exact roof area and the number of drains is precise work so it requires coordination. The above sizing data is offered as a guide only. This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table. Jun 28 2020 explore casdesigns s board roof drainage on pinterest.

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. Take the roof s total square footage and divide by the total square footage handled by one drain. You also must include half of the area of any vertical walls that may divert rain to the roof. Last updated 26 aug 2016.

The result is the number of drains needed. See more ideas about rain water collection rain water collection system roof. The next step is to determine each roof area that will be served by a separate leader drain pipe scupper or downspout. Lysaght rainwater solutions vic tas guide pdf 1 6 mb.

To prevent erosion make a rock bed around the end of the tube. Lysaght rainwater solutions qld guide pdf 2 2 mb. Box gutter with rain water head at end of box gutter. The effective roof area to be drained.

The flow characteristics of the gutter system. 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. Last updated 27 feb 2019. Rainwater drainage is covered by building regulations part h3.

The number and position of downpipes. Screw a drain cover over the end of the tubing as it approaches daylight to keep critters out. Last updated 23 jan 2019. You can view information on the design of roof drainage systems in the brochure for your state.