Flat Roof Drainage Design Guide

Most flat roofs suffer from poor drain locations or drain levels that are high.

Flat roof drainage design guide.

To help you choose the right one here s a guide to the five best flat roof drainage systems and why they re such a vital part of keeping it in perfect condition. The result is the number of drains needed. 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. What is the general area of a flat 1 4 1 0 slope single ply roof for each roof drain ratio for the number of roof drains roof area.

The following outlines ways to build protect and reinforce your roof. Guide to flat roofing drainage systems and epdm. Having sufficient drainage on a flat roof is vital. They require a root barrier to stop the plants interacting with the waterproofing beneath and a flat roof in particular requires a drainage layer to retain water.

Along with the benefits of a flat roof come unique challenges. Some pipes are too small to handle the volume of the water. There are many advantages to using a flat roof. This guide explains the advantages and disadvantages of the three most common flat roof drainage solutions.

Interior drains gutters and scuppers. 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. There is a wide variety of flat roof materials available each with its own advantages and drawbacks. With a new structure in the design stages or part completed you need to know that your blueprint is going to work.

The most critical of these issues is the flat roof drainage systems. Built up roofing bur this multi layer roof design is a proven system that has been around for generations. The above sizing data is offered as a guide only. Here we ll discuss types of flat roofing.

Flat roofing does not drain naturally like sloped roofs that can rely on the force of gravity to remove water. This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table. By mark brinkley 26 may 2020. Calculate drains needed.

The good news is that there are a variety of drainage options for your flat roof each with their own benefits and drawbacks. Your building and location can help determine which drain will fit your roof needs. Take the roof s total square footage and divide by the total square footage handled by one drain. Of course the best designed flat roof has the correct amount of pitch to drain the water off naturally.

On many occasions drains are too high and water cannot flow off. 6 24 2014 david howard aia said. When designing a roof it is essential to pay close attention to where the drains are. Flat roof design guide some bauder waterproofing systems are bba approved for use with zero falls but back falls are not acceptable and should be corrected.

Choosing a flat roof design.