Drainage Systems for Your Flat Roof

Drainage Systems for Your Flat Roof

The architectural style of commercial properties can vary from one building to the next. But while commercial buildings might look different from one another, many share a common feature — a flat roof. Flat roofing has been used for many years in commercial settings to help increase the amount of usable space within the building while keeping installation and maintenance costs low.

A flat roofing system depends on reliable drainage to retain its integrity and energy efficiency. Since flat roofs have minimal slopes, water can pool on the surface when proper drainage is not present. This pooling water can cause the roofing membrane to deteriorate, leaving your commercial building susceptible to leaks.

Choose the right drainage system for your flat roof to extend the life of the roofing materials protecting your commercial space.


One of the most basic types of drainage systems you can pair with a flat roof is a series of rain gutters. Gutters are attached to the edges of the roof. Water moves off the surface of the roof and into the gutters. Downspouts and leader pipes then funnel this water safely away from the foundation of your building.

Gutters only work if they are kept clean and clear. Any debris that builds up in the gutters can restrict the flow of water. Also, clogged and dirty gutters can lead to standing water on your flat roof, putting the integrity of the roof membrane at risk.

If you do opt to rely on gutters to drain water off your flat roof, be sure that you invest in regular gutter cleanings to keep the drainage system working efficiently.

Interior Drains

Larger commercial roofs can benefit from interior drains. This type of drainage system consists of drains that are placed at regular intervals near the center of the roof. These drains are connected to a series of gutters and pipes that help transport water from the center of the roof to the roof’s edges.

Interior drains can empty into the rain gutters, or they can be connected to a separate drainage system to ensure maximum drainage capabilities. Either way, the system is built into the roofing membrane. This means that they are virtually undetectable to anyone looking at your commercial roof. This feature helps to preserve the aesthetic of your commercial building.

Be sure that you incorporate protective screens if you opt to install interior drains so that dirt, debris, and animals cannot enter the drainage gutters and pipes and create clogs that will prevent proper drainage.

Selecting the right drainage system for your flat roof will have a direct impact on maintenance costs and the effectiveness of your roofing system. Contact A-1 Roofing Inc. for help selecting and installing the drainage system that will best meet your flat roof’s water removal needs.

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