Flat Roofs: Strategies For Effective Water Drainage

Posted on: 31 August 2023

Flat roofs can be challenging when it comes to water drainage issues. The lack of an angled pitch can cause water to accumulate and form pools, leading to damage, leaks, and mold growth. To prevent these issues, you need to implement effective water drainage strategies. 

This article discusses the most common techniques for ensuring flat roofs have proper water flow. 

Use of Tapered Insulation

Tapered insulation is a well-recognized and effective method employed to enhance water drainage on flat roofs. This system is designed to create a subtle slope on an otherwise flat surface, which aids in channeling the water toward the roof drains. 

The insulation is typically made of polystyrene or polyisocyanurate foam, and the thickness varies across the roof to create the desired slope. This effectively eliminates the water pooling issue.

Implementation of tapered insulation is a fairly straightforward process. The insulation panels are arranged in a way that they incline towards the drain points. This process requires professional assistance to ensure correct installation and slope precision.

The precision in the slope is crucial, and the standard rule is an incline of less than an inch per foot to create an adequate flow of water toward the drains.

Installation of Roof Drains

Roof drains are essential for any flat roofing system to ensure excess water gets drained out properly. When installing these drains, proper spacing and positioning are important factors, because they can make or break a drainage system. 

Roof drains should be placed where water tends to puddle and accumulate. Furthermore, the drains should be placed where debris is unlikely to clog them up. Generally speaking, the ideal drain spacing for a flat roof is a couple of feet apart. However, this may vary depending on the roof size and shape. 

Installing these roof drains requires experience and expertise because it involves drilling holes in the roof membrane. To avoid any damage to the membrane, get an experienced professional to install them.

Installation of Rain Collars

A rain collar is an important element of a flat roof drainage system. It's a metal or plastic ring that fits around the base of the drain pipe and acts as a barrier against any leakage. This ensures that no water seeps through the hole where the pipe is inserted. This can cause significant damage to your roofing membrane.

Furthermore, it also provides an additional layer of protection against debris and leaves, which can clog up the pipe. 

When it comes to selecting a rain collar, make sure you get one that is compatible with your roofing membrane and fits snugly around the drain pipe. Moreover, always ensure it provides enough slope toward the drainage outlet. Get in touch with a professional roofer for more information on water damage on flat roofs.