Flat Roof Drainage System Design

Size horizontal storm drainage piping.

Flat roof drainage system design. More attention should be given to the location of a drainage system to avoid future problems. 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. An interior drainage system makes use of several drains spaced across the surface of the roof most commonly near its center. Cities based on inches per hour that may fall during a storm of one hour duration and a 100 year return period.

In order to ensure a finished surface with zero fall a design fall of 1 80 should be used and a detailed structural analysis should account for construction tolerances settlement and for. Buildup of rainwater on a roof can cause structural damage and leaks. Appendix b in the ipc provides rates of rainfall for various u s. Improper gutter drainage can cause erosion of soils and foundation issues.

Please see roof drainage calculations for a detailed answer to your question. Of course the best designed flat roof has the correct amount of pitch to drain the water off naturally. If it hasn t that s a sign of a problem with roof drain parts or the drainage system. Flat roof drainage options.

The most critical of these issues is the flat roof drainage systems. Along with the benefits of a flat roof come unique challenges. To design a sloped or flat roof drainage system we need to know the anticipated maximum rainfall rate and the flat or projected roof area. To help see where any water might be collecting clean any debris from the flat roof surface including sweeping or gathering fallen leaves or branches and clearing any loose debris or gravel that may block drainage holes.

There are a few ways to make sure water drains away from the surface of a flat roof. Size vertical storm drainage piping. Below are the five best roof drains for flat roofs. The maximum rainfall rate anticipated in the area where the building is located the flow in liters per minute per square meter for some x number of minutes.

This data is available in excruciating detail for most countries in weather map form and as you ll read. I examined several roof drainage calculators and tables to see what they tell us. Select number of roof drains and calculate the roof area sloped to each drain. Your building and location can help determine which drain will fit your roof needs.