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7 Common Problems With A Flat Roof & How To Prevent It

Posted on June 29, 2024

flat roof problems

Flat roofs have gained popularity in recent years due to their modern appearance and efficient use of space. However, they come with their own set of challenges, which you should know about. Learning about the potential issues beforehand can help you take care of your roof better and ensure that it lasts longer. 

In this blog post, we will explore seven common problems associated with flat roofs and provide practical tips on how to prevent them from occurring.

#1 Ponding Water

Ponding Water on Flat Roof
Ponding Water on Flat Roof

One of the most prevalent issues with flat roofs is ponding water. This occurs when water accumulates on the roof’s surface and fails to drain properly. Flat roofs aren’t entirely flat, but they do have extremely low slopes of about ¼ inches per 12 feet. This makes it difficult for water to drain off the roof, even more so if there are frequent rain showers.  

Over time, this standing water can cause leaks, damage the roofing material, and potentially lead to structural problems. The longer standing water stays on the roof the more damage your building will face. 

To prevent ponding water, it is crucial to ensure proper drainage. This can be achieved by maintaining the recommended slope (at least a quarter inch per foot) and keeping drains and scuppers clear of debris. Gutter health also plays an important role. Regular inspections and cleaning will help identify and address any drainage issues before they become severe.

#2 Shrinkage and Cracks On the Flat Roof

Flat roofing materials like single-ply membranes are susceptible to shrinkage. Even the best products can shrink and even crack due to temperature fluctuations and exposure to the elements. 

How does this happen? As the roofing material expands and contracts, it can develop cracks. Though most materials are resistant, cracks will still occur if your roof is exposed to harsh conditions and excessive UV rays. This can allow water to seep through and cause leaks and other forms of damage.

To fix cracks or membrane shrinkage on your flat roof, it is essential to use high-quality roofing materials made by top manufacturers. Proper installation techniques, including adequate overlapping and sealing of seams, will also help prevent these flat roofing problems. Additionally, regular inspections can identify and address any cracks or signs of deterioration before they become major issues.

#3 Blistering and Ridging

Roof blistering is a serious issue for both residential and commercial flat roofs. While cracks are common in single-ply roofing systems, blistering is common among built-up roofing (BUR) or modified bitumen membranes. These issues are often caused by trapped moisture or poor ventilation, which can lead to the separation of the roofing layers and the formation of bubbles or ridges.

To prevent blistering and ridging, it is crucial to ensure proper ventilation and the installation of vapor barriers. Regular maintenance, such as cleaning and repairing any damaged areas, can also help extend the lifespan of the roof and prevent these issues from occurring.

To learn more about this issue, check out our blog post on: What Is Roof Blistering And What To Do About It

#4 Roof Punctures

Roof Punctures
Roof Punctures

Flat roofs are susceptible to punctures and tears. These are holes in the roof that develop along the membrane and make the layers underneath vulnerable. Hailstones are the biggest culprit when it comes to punctures. However, this can also be caused by foot traffic, dropped tools, or other objects. Make sure the roofer you hire handles his tools properly as in most cases the roofing tools will cause the punctures. 

Even minor punctures can allow water to seep through, leading to leaks and potential structural damage.

To avoid punctures and tears, it is advisable to limit foot traffic on the roof and provide designated walkways or pathways. Using walkway pads or other protective materials can also help prevent punctures. Hiring an experienced and responsible roofer is a must! 

#5 Membrane Degradation

Over time, the roofing membrane on flat roofs can degrade due to exposure to UV rays, chemicals, and other environmental factors. This degradation can compromise the integrity of the roof, leading to roof leaks and other issues.

To prevent membrane degradation, it is crucial to use UV-resistant and weather-resistant roofing materials. Avoiding the use of harsh chemicals or solvents near the roof can also help prolong the life of the membrane. Regular inspections and maintenance, such as recoating or resurfacing the roof, can also help address any signs of degradation.

#6 Flashing Issues

Flashing is the material used to create a watertight seal around the vulnerable areas of your roof such as vents, pipes, and chimneys. Flashing is just a small piece of metal or rubber, but plays a crucial role in your roof’s overall durability and water resistance. 

Improper installation or weathering can cause flashing to fail, allowing water to penetrate and cause leaks.

To prevent flashing issues, it is essential to ensure that it’s properly installed by a professional roofer. Using high-quality flashing materials and following the manufacturer’s instructions is also important. Regular inspections and maintenance can help identify and address any failing or damaged flashing before it becomes a significant problem.

#7 Vegetation Growth

Flat roofs can sometimes become a breeding ground for vegetation growth, such as moss, algae, or even small plants. This growth can retain moisture, potentially leading to leaks and accelerating the deterioration of the roofing material.

Cleaning your roof regularly and making sure it is free of debris is the most effective way to avoid unwanted growth. Regular cleaning and the application of herbicides or biocides can help inhibit the growth of unwanted vegetation.

Additionally, ensuring proper drainage and addressing any areas of standing water can discourage vegetation from taking root.


Flat roofs have a modern and stylish look, but they need regular care to avoid common problems such as water pooling, cracks, blisters, and tears. It’s important to have your roof checked regularly and fix any issues as soon as possible. By staying on top of maintenance, you can keep your flat roof in good shape for a long time.

Fix Flat Roof Problems Today With Prestige Roofing 

If you neglect the possibility of these problems occurring when installing a flat roof, you may end up facing more problems than you originally expected, costing you more money in the end To avoid this, it’s important to hire the experts, like our team at Prestige Roofing LLC. 

We are a premier roofing company serving De Pere and the surrounding areas of Northeastern Wisconsin. We know that harsh weather conditions can take a toll on your roof, which is why we make sure that you get the most professional and durable commercial roofing services. 

Contact us today at (920) 791-0414 to speak with one of our professionals and find out how we can help you.  


Do Flat Roofs Have No Slope?

Flat roofs have a slight slope, usually between ¼ to ½  inch per foot, to ensure proper drainage. This minimal slope prevents water from pooling, reducing the risk of leaks and damage over time.

How Much Does a Flat Roof Cost?

The cost of a flat roof varies widely, typically ranging from $4 to $30 per square foot. Factors influencing the cost include materials, labor, roof size, and geographic location.

How Long Do Flat Roofs Last?

Flat roofs typically last 10 to 25 years, depending on the material and level of maintenance. High-quality materials like PVC or TPO can extend the lifespan, while regular maintenance helps prevent premature wear.