3 Causes of Water Pooling on Your Flat Roof 

As homeowners, we tend to overlook roofing issues until it starts to leak. You may have a flat roof and noticed water pooling.  

What is water pooling? Water pooling is standing water on your roof, after a heavy rain that won’t evaporate by 48 hours mainly related to a variety of roofing problems. 

Below, we share the three main causes of water ponding and simple tips to prevent them.  

1. Malfunctioning Drainage System

Three ways a flat roof drains water: 

• Water can be drained through the roof scuppers which allows water runoff to exit through a metal edge, parapet wall, or through the deck into a downspout.  
• A slope/ pitched part towards the gutters to allow positive water flow.  
• A faulty drainage system is the most common cause of water pooling on your flat roof. When you have a poor drainage system, the water will not drain effectively and therefore will stand on your roof, especially since there is no slope that tends to drain the water away naturally.  

A simple way to prevent water from standing on your flat roof would be to have your drain and gutter system cleaned and maintained consistently for the water to flow out effectively.  

2. Bad Roof Design

The structure of your roof should also be an element to consider. For example, a roof that’s poorly designed or has low spots due to a variety of reasons can attract water ponding.  

Water pooling additionally happens when your roof gutters are improperly installed, which makes your drainage system inefficient.  

3. Damaged Roof Insulation

When installing heavy construction materials on your flat roof (e.g. HVAC equipment), that will compress the roof insulation layers.  

Flat roofing insulations tend to be sensitive and worsen when exposed to water. When that happens, the insulation layer loses its shape and creates indentation/ low spots on your flat roof where water stands.  

Water pooling can become a threat to your home as it can lead to a leak over time. Therefore, it’s important to act as soon as possible before the issue worsens.  

If you have a flat roof and have noticed water ponding on it, you can contact us to determine the cause of the issue and the best suggestion to immediately overcome it.