Because commercial flat roofs drain a bit differently than traditional sloped roofs, they are more prone to issues such as pooling water. Pooling water, also called ponding water, is when areas of a flat roof have standing water. The water can be several inches deep and takes more than 48 hours to drain or dry. Here, we take a closer look at pooling water on commercial roofing systems and how property owners can utilize regular commercial roof maintenance to minimize this common problem.
Understanding the Problem Behind Ponding Water
If you’re a property owner with a flat roof, chances are you’ve encountered the issue of ponding water. As noted above, this problem occurs when water pools on your roof’s surface and is unable to drain off within 48 hours. It can cause significant damage to roofing materials over time and even threaten the integrity of your building structure.
Pooling or ponding water typically occurs due to insufficient drainage or lack of slope in certain areas of the roof, leading to sagging roofs that hold rainwater instead of letting it flow away naturally.
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Causes and Consequences of Ponding Water on Flat Roofs
As with any roofing issue, it’s important to understand the causes of the problem and the impact it can have on your roof. Here are some potential causes and consequences of pooling water on your commercial roofing system:
What Causes Ponding Water on Flat Roofs?
- Crushed or compressed insulation
- Improper roof installation
- Malfunctioning drains
- Poor roof design
- Sagging roof deck
Consequences of Leaving Ponding Water
- Damaged roof structure
- Leaks and water damage
- Roof membrane tears
- Sagging roof deck
- Vegetation growth
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Prevention and Solutions for Ponding Water on Flat Roofs
It is possible to prevent standing water from becoming an issue on flat roofs. If your roof consistently has large, deep pools of standing water for over 48 hours after it rains, it’s time to call in a professional roofer to assess the problem.
Building owners can prevent pooling water by:
- Cleaning drains. Blocked drains often lead to rooftop pools after heavy rain. Ensuring your roof has sufficient drainage prevents the need for constant repair or even roof replacement.
- Ensure proper insulation. Tapered insulation plays a crucial role in controlling ponding water by providing built-in slope–an easy way to encourage water to drain off your roof surface quickly.
- Add roof crickets. Making alterations like adding crickets, or small slopes, towards existing drains may solve pooling problems without requiring a total roof deck reconstruction.
- Roof coatings. If these adjustments aren’t enough, consider consulting your roofer about waterproof membranes that cover vulnerable areas where stagnant excess water tends to build up over time.
The Role of Proper Installation and Design in Preventing Ponding Water
Proper roof design and installation go a long way in preventing ponding water on flat roofs. During installation, your roofing contractor should ensure a slight pitch or slope to properly drain water. High-quality roofing materials and expert installation can also help ensure seam integrity to prevent tears and leaks from heavy areas of pooling water.
A proper drainage system is also crucial. Smart design allows rainwater to flow off your roof without creating puddles. The right drainage system that is designed for your roof size and material combined with parapet wall scuppers can dramatically reduce instances of pooling water. Don’t forget to keep your drains clear and your roof maintained to prevent issues from ponding water.
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Hiring a Professional Roofing Contractor for Ponding Issues
When dealing with ponding water on your flat roof, the best course of action is to hire an experienced commercial roofing contractor.
The right professional can identify whether the issue lies in improper installation or if it’s due to age-related settling of the building foundation. This expertise helps save you time, money, and future headaches when dealing with a roofing issue.
Finding the Right Roofing Contractor
Look for local, certified commercial roofers who understand how flat roofs work and have experience with different issues and materials. They should also have experience with your particular drainage system to address ponding water issues effectively.
Maintaining Your Flat Roof Post-Repair
After repairs are done, regular maintenance becomes essential. Keep in mind that even small changes like removing debris from drains regularly can make a huge difference over time by preventing ponding issues from reoccurring. Your roofer can help set you up with a regular maintenance program to prevent issues and prolong the life of your roof.
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FAQs About Pooling Water on Flat Roofs
Is it normal for water to pool on a flat roof?
Water pooling can occur after rain, but if it stays longer than 48 hours, you’ve got a problem that needs fixing.
How do you fix pooling on a flat roof?
It depends on what’s causing the issue, but you may be able to fix pooling water by cleaning drains, improving the slope of the roof, or getting professional help from a local roofing contractor.
How much pooling is acceptable on a flat roof?
Standing water up to 36 hours post-rainstorm isn’t uncommon, but anything beyond two days requires attention.
Is it okay to have standing water on a flat roof?
Yes, but not for extended periods. Standing water that doesn’t go away can damage your flat roof and even compromise your building’s structure.
Get Your Roof Inspected With Us
If you’re dealing with pooling water on your commercial flat roof, contact CDS Roofing. As a professional commercial roofer, we can help you identify the source of the problem and correct the issue to ensure your roof properly drains water for a safe and effective system.
