Hail Damage on Flat Roofs

The Risks of Hail Damage on Flat Roofs in Shoreview, Minnesota: What Homeowners Need to Know

It has become quite the trend for people to use flat roofs for their homes. In the past, this was common for commercial roofing. However, that has changed with time, and people are now embracing flat-roof houses as part of modern architecture. 

A flat roof property is often preferred because this type of roof is cheaper and offers more functionality compared to a house with a roof pitch. Being broad and obstructed can benefit the owner but also mean the roof is prone to hail impacts. Hail varies a lot, from small pellets to big golf-ball-sized stones. So, if the area tends to receive hail stones, they can impact the flat roof structure. 

Flat roof hail damage could also mean water damage, which is the hardest to deal with. You might consider having proper drainage on the flat roof, but there is more to this. We want to look at that below and also, how a flat-roof house insurance policy can benefit you.

Understanding Flat Roofs and Hail Damage

If you are a real estate agent, you might have quickly noticed how flat roofs in residential areas have grown in popularity. People can now use their flat roofs as additional space to set up gazebos, chill spots, and much more. As much as this is the case, if the design and construction are not done correctly, water damage issues can occur.

Most flat roofs slightly slope around ¼ to ½ inches per foot. This is enough for water to run off so the roof does not have water damage issues. Also, maintenance of flat roofs is easier since you can just walk on them, identify where the issues are, and start working on them. The same cannot be said for pitched roofs. 

Common materials used in flat roofs include;

  • Built-Up Roof (BUR): This traditional flat roof material combines several layers of bitumen with reinforcing fabrics, leaving you with a strong membrane as part of the flat roof. 
  • Modified Bitumen is similar to the BUR mentioned above but easier to install. It also includes layers of asphalt and fiberglass or fiber matting, which are key to strengthening this roof material. 
  • EPDM rubber roof: This rubber membrane is one of the most common options today for your flat roof and an alternative to a metal roof. Since you will be layering several sheets of rubber, it becomes easy to achieve. Also, the material is resistant to various weather elements. 
  • Thermoplastic Membrane (TPO and PVC): These are lightweight reflective membranes used on flat roofs. The construction of these membranes makes them resistant to UV light, bacterial growth, and chemicals, ensuring the best durability. 

There can be many other types of flat roof materials. It all depends on the contractor and what you want to achieve. Ensure the material is good enough to withstand elements such as hailstones. 

Cons of Flat Roofs in Hail Prone Areas

We are already aware of the pros of flat roofs; however, this could also be a downside, especially in places where hailstones are quite common. Below are some of the cons of having flat roofs in hail-prone areas. 

  • The flat roof surfaces are more susceptible to direct hailstone impact. This can seriously damage the membranes used to cover the flat roof. This damage is now what leads to other roof issues later.
  • As much as flat roofs would have a slight slope to aid drainage, sometimes too much rain and hail stones can lead to water pooling. This then leads to structural damage or leaks if not well handled. 
  • If you live in a hail-prone area, you might need regular maintenance on your flat roof to mitigate such problems compared to those living in less hail-prone areas. 

How Hail Can Affect Flat Roofs

Hailstones could hit the flat membrane roofing while traveling 45 to 70 miles per hour, showing that damage is possible at such an impact. Commercial properties have long used various methods during flat roof installation to mitigate this issue. However, can a commercial flat roofing keep up with time?

That is why we want to see how hailstones affect different materials used for flat roofing, whether residential or commercial. 

EPDM rubber is quite resilient when used in commercial roofing, but experiencing consistent large hailstones can puncture the EPDM roofing. It is possible for this membrane roofing to absorb the impact of the small hailstones, but it is not the same when you have bigger hailstones. 

As for modified bitumen, you will notice that the material would resist hail impacts better; however, the material can still suffer surface bruises or structural damage in the case of larger hailstones. 

TPO and PVC membranes are strong against hailstones but can shatter or crack in case of extreme hail impacts. This is common in colder weather when the material is less pliable. 

BUR membranes can work well if you add several layers of this material to the flat roof. However, in the case of continuous hailstones, the top layer can be stripped away, exposing the underlying materials and causing further damage. 

Early Signs of Hail Damage

Before starting the whole process of flat roof replacement, it is good to know the visual indicators of hail damage to better understand the problem. 

Dents are the most obvious indicator that your residential or commercial flat roofs are experiencing hail damage. The dents’ size and depth depend on the dents’ size and depth. The deeper the dent, the larger the hail stones. 

Sometimes, punctures can occur in EPDM rubber or other flat roofing materials. The punctures or deep gouges are easily visible to the naked eye, and when this happens, the roof loses its waterproof integrity. 

Consistent hail storms also cause a lot of surface damage. Commercial roofing contractors easily identify cracked or shattered areas on the roof, mostly for TPO or PVC roofing material. In addition to dents, you can also see patches on the roof where the hail stones have stripped away the granules on the roofing material. 

Those are just the most common visual signs of hail damage. However, hidden signs can also occur. These include water leaks, structural weakening, and mold and mildew growth. The contractor usually determines these during the inspection process. 

Long Term Considerations 

Repairs remain the best thing you can do for your residential or commercial flat roof. You must always take the first step in inviting the flat roof contractor to inspect and repair the roof when necessary. It helps you mitigate the issues faster before they become an issue later. 

The age of flat commercial roofing systems can also be a factor. When the roofing material reaches the end of its lifespan, no amount of roof repair will help. It even becomes more cost-effective to replace the flat roof rather than repair it again. 

The extent of the damage is also an important factor. A full replacement is better if the damage could affect the roof’s structural integrity.

Consider the frequency of roof repairs. If you find yourself having a roofing contractor over more often, it means the roof is failing, and you are better off replacing it to avoid incurring more costs in repairs and still replacing the roofing membrane eventually. 


Flat roofs look good and can be more practical in some cases rather than having the pitch roof type. You must understand which material was used to protect the flat roof from elements such as hailstones. If you live in hailstone-prone areas, make sure that you always take a step further to reinforce the flat roof and still have scheduled inspections to check if your roof is still in good condition.

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