Flat Roof Patio Drainage

Poor drainage can lead to serious issues with flat roofing from leaks to structural damage.

Flat roof patio drainage.

Keep in mind all flat roofs have a slope of between five and 15 degrees to allow water to flow into drain systems such as eaves drainage holes or outlets. Here the rubber roof will need to run up the walls and glue to the sheathing. However flat roofs suffer from poor drainage. To keep water from pooling at these inside corners tom rips 2x4s lengthwise on a 45 degree bevel with a table saw.

Unlike other roofing types that are slanted or sloped to allow water to drain automatically flat roofs need a built in drainage system to help remove moisture and debris. The one challenge with flat roofing is ensuring proper drainage. The most critical of these issues is the flat roof drainage systems. 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.

Patio drainage water pooling on a patio or deck can cause mildew growth can stain concrete and creates slippery conditions. Find concrete patio contractors near mewho can assess and fix my drainage problems. On two sides the roof abuts a parapet a short wall common around flat roofs as well as a wall for the third floor. To keep damage like leaks from occurring water should not stand on a flat roof for more than 48 hours.

Once all the parts of the drainage system were installed we covered the tubes with several inches of rock. The angle is not significant enough to prevent water from pooling on the surface. Your building and location can help determine which drain will fit your roof needs. Of course the best designed flat roof has the correct amount of pitch to drain the water off naturally.

For clarity flat roofs actually have a slight slope to allow rain water to drain off the roof but they seem flat when compared with more traditional steeply sloped roofs. The slope should be a minimum of 1 in 80 but in practice a minimum slope of 1 to 40 should be used to allow for deflection of the roof and for normal building tolerances. It is essential to install a drainage solution into your flat roof to remove debris and moisture that should not be there. It can suffer from water accumulation because of the lack of incline and therefore lack of forces of gravity that give way to natural water runoff.

If your patio is completely flat and has low spots where the water collects it needs to be angled or sloped slightly so the water will run off the surface much like a roof gutter is sloped to direct water to the downspout.