How To Stop Ponding Water on Your Flat Roof 

If you’ve noticed standing water on your flat roof, you’re not alone. Flat roofs are great for a lot of reasons — they’re durable, cost-effective, and easy to maintain compared to some other roofing styles. But with flat roofs, there is a serious concern involved, which is known as ponding or standing water. 

When it starts to rain (which is fairly common in Mississippi), water can start to accumulate. If this standing water overstays its welcome, meaning that it lasts for more than 48 hours, it can lead to some serious problems. Don’t worry, though, this is what this blog post will address today. 

We are a roofing company with years of experience working on flat roofing systems. Seeing so many questions from homeowners, we decided to address one of them with a detailed guide. In this article, we’ll walk you through why ponding water happens, the risks it poses, and, most importantly, what you can do to fix it. Let’s dive right in!

Why Is Water Ponding On My Flat Roof? 

No roof is truly flat, even the ones called flat roofs have a slight slope so that it can shed rainwater away from the building. This gentle angle, while subtle, is crucial for allowing water to flow off the roof and into the drainage system. When everything is working as it should, water runs off smoothly, and your roof stays in great shape. But when there is too much rain, the slight slope might not be enough, and water starts to pool. This is what we refer to as ponding water, or pooling water. 

Ponding water refers to any water that remains on your flat roof for more than 48 hours after heavy rain or storm. It might look like a harmless puddle, but it’s actually a red flag. Your flat roof is only designed to handle minimal exposure to water, but there is a limit. 

Here are some of the main reasons ponding water might occur on your flat roof:

• Clogged Drainage Systems: Leaves, dirt, and debris can block your roof drains or gutters, leaving water nowhere to go.
• Settling Over Time: Roofs can develop low spots as they age, making it easy for water to collect.
• Improper Design or Installation: If your flat roof wasn’t installed with the right slope or drainage points, water might pool in certain areas.
• Structural Damage: Heavy equipment (like HVAC units) or long-term wear and tear can weaken the structure, leading to sagging areas.

Why Ponding Water Is A Big Deal And Why You Should Fix It Immediately

You might think that since it’s just water, it will evaporate, but don’t jump so quickly to that conclusion. Standing water on your roof can lead to a whole host of issues if it’s left unchecked. Here’s why you should take it seriously:

• Increased Risk of Leaks: Water finds its way into the smallest cracks and seams, especially if the roof’s protective layers are worn down.

• Structural Damage: Though not as common, frequent water pooling can cause damage to your structure. Over time, the extra weight of standing water can cause parts of your roof to sag, making the problems worse.

• Damage to Roofing Materials: Prolonged exposure to water can degrade certain roofing materials, like modified bitumen, leading to expensive repairs.

• Mold and Algae Growth: Stagnant water is a breeding ground for mold, algae, and other nasty stuff you don’t want near your building.

• Shortened Roof Lifespan: A roof that deals with frequent ponding won’t last as long as one that’s properly maintained.

How To Fix Ponding Water 

Now that we know what causes water to pool on your roof it is time to learn how to stop it from happening. Fortunately, there are some remedies for water ponding on a flat roof that you need to keep in mind. 

Inspect the Roof Regularly

First things first: you need to know what you’re dealing with. Schedule regular roof inspections (ideally twice a year) to catch potential problems early. After a heavy rainstorm, check for standing water and note where it collects.

During your inspection, look for:

• Clogged drains or gutters
• Sagging areas
• Visible cracks or damage to the roofing material

If you’re unsure what to look for, that’s where professionals (like us) come in. We’ll spot the issues you might miss.

Clear Out Drains: 

One of the major reasons why water pools on your flat roof is because the drains are not doing their work efficiently. This can be due to the drains being clogged, and if that’s the case, simply cleaning the drainage system thoroughly can do wonders.

Here is what you can do: 

• Remove debris, dirt, and leaves from drains, gutters, and scuppers.
• Consider installing drain covers or mesh screens to prevent future clogs.
• For persistent clogging issues, you might need to upgrade to a more robust drainage solution.

Reinforce Low Spots

For areas where the roof has sagged or settled, you’ll need to level things out. This can involve applying a specialized roofing material, like a self-leveling compound, or installing tapered insulation to create a slight slope.

Tip: Don’t DIY this unless you’re confident in your roofing skills. It’s easy to make things worse if you’re not careful. 

Improve Drainage Systems

If the issue is poor drainage design, you might need to make some upgrades to your system.

• Add More Drains or Scuppers: Increase the number of drainage points to give water more escape routes. You can do this by adding roof scuppers. These are openings created on the edge of a flat roofing system to let rainwater pass.  
• Redirect Water Flow: Use tapered insulation or roof crickets (small structures that guide water) to direct water toward drains. Tapered insulation also adds more of  a slope to your flat roof. 
• Install a Secondary Drainage System: As a backup, this ensures water doesn’t linger even if the primary system fails.

Apply a Waterproof Coating

Though most flat roofing materials such as TPO and EPDM have water-resistant capabilities, they can still fail when there is a heavy downpour. A good waterproof coating can act as an additional shield for your roof, protecting it from standing water. These coatings are especially useful if your roof is nearing the end of its lifespan but isn’t quite ready for a full replacement.

Here are the types of roof coatings that you can install on your flat roofing system to fix the problem of water pooling.

• Acrylic roof coatings
• Silicone roof coatings
• Polyurethane roof coatings

Consider Replacing Your Flat Roof

If your flat roof is older, severely damaged, or ponding water has become a frequent problem, it might be time to seriously consider a full roof replacement. While repairs can often extend the life of a flat roof, there comes a point when constant patchwork is no longer cost-effective. A replacement might seem like a significant investment upfront, but modern flat roofs are designed with improved materials and advanced drainage systems that offer better long-term performance and durability.

With options like PVC, TPO, or EPDM membranes, modern flat roofs provide enhanced resistance to standing water, UV rays, and temperature fluctuations. They’re also more energy-efficient, which can help lower heating and cooling costs over time.

Why Call a Professional?

You might be tempted to handle ponding water yourself, and while there are small fixes you can tackle, bigger issues are best left to the pros. Here’s why:

• We have the tools and expertise to pinpoint the root cause of the problem.
• DIY fixes might provide temporary relief but can lead to bigger issues down the line.
• Roofing systems are complex, and mistakes can be expensive.

At the end of the day, it’s better to have a professional assessment. That way, you know the job is done right the first time.

Trust Us For Flat Roofing Services In Mississippi

Struggling with constant damage to your flat roof? Look no further than the team of B & A Roofing and Gutters. We’ve helped countless homeowners and businesses address ponding water and extend the life of their roofs. Whether you need an inspection, repair, or full replacement, we’re here to help. Contact us today at (601) 520-3183.