How To Divert Water On A Flat Roof

How to redirect rain off a roof.

How to divert water on a flat roof.

Place a piece of standard metal drip edge onto a table or between a pair of sawhorses. A french drain uses a perforated pipe placed in a gravel filled trench to direct water flow while allowing slow seepage along the drain s path. They catch rainwater as it rolls off the edge of the roof and divert the water into a downspout that dispenses it a safe distance from the foundation of the building. When it comes to pooling on your flat roof you might find that the water ponds in specific areas.

Turn it upside down so the lip edge faces upwards. One of the more intricate methods of controlling water flow around a building or property is by using french drains. The best way to battle water ponding in these areas is to install roof crickets in those areas. Gutters are the most commonly used and most cost effective drainage solution for flat roofs.

The clark county extension recommends using french drains to divert roof rain water to ponds or a perforated pipe system to slow the water flow. Score the surface of the drip edge with 80 grit sandpaper. For a large roof it is recommended to have drains placed at multiple locations within the area of the roof. On a performing flat roof ponding water is not a problem as it will drain or even evaporate away.

These areas typically are near chimneys or around large vents. Trench drains are concrete lined channels that help direct water flow while filtering out debris using grates or filters to reduce clogging. However when your flat roof has uneven areas due to sagging an insufficient slope or drainage issues the ponding water doesn t dissipate. For flat roof drainage where you place your drains scuppers and the final material of the roofing is more important.