GRP Roofing Problems

Home Roofs GRP Roofing Problems
fibre glass roofing

GRP roofs, also known as glass-reinforced polyester roofs, fibreglass roofs, or flat roofing, is one of the most popular choices for a variety of reasons. It’s commonly used on extensions and garages and can be one of the most convenient and cost-effective roofing solutions since it takes much less effort and labour to install than the alternates. Like all types of roofing, however, problems can arise with them over time. Here, we’re going to look at some of the problems you might have with your GRP roof, as well a few tip and tricks to keep on top of them.


For one, all roofs have a certain life expectancy. For GRP roofs, this can reach up to 50 years, well over the average flat roof. However, when it reaches that age, it can lose its elasticity, causing it to look cracked and wrinkled like the skin of an alligator, hence the term. If you spot this problem, you’re most likely in need of a replacement.


GRP is highly water resistant, so it’s not as prone to leaks as felt flat roofs. However, water can still collect on the flat surface of the roof easily. If left there, it can potentially cause leaks and structural issues over time. This is known as ponding. You can use hoppers or install automatic pumps to drain any excess water or use tapered roof insulation to prevent water from infiltrating.


Sometimes, you may notice that lots of miniscule pinholes start to appear on the exterior surface of the roof. This is primarily down to insufficient resin being used during the building process. This can lead to problems like leaks over time, but it can be fixed by key sanding the roof and making sure that the proper amount of topcoat is applied this time.

Flaking or cracking

Similarly, reapplying the topcoat can fix any problems with flaking or cracking on the surface of the roof. This most often happens if the topcoat is applied too quickly or on top of still-wet laminate.

Splits or holes

A flat roof has to sustain a lot more pressure than other shapes of roof. Because of this, sometimes splits or holes can appear when that pressure becomes too much. So long as the wood underneath the GRP roof is dry, you can hire a professional to apply the fibreglass on top of it once more and it should be as good as new again.


Like all roofs, the gutters of your GRP roof can susceptible to problems if they are not regularly maintained. This is more common in flat roofs that are closer to the ground, as they are prone to debris, and leaves finding their way into the gutter. Ensure you clean out the gutter every season to stop blockages, which leads to water build-ups that can cause leaks into the roof.

Despite the issues above, GRP roofs remain popular thanks to the strength of fibreglass. With high tensile strength, great insulation, fire and water resistance, they could be the perfect solution for your property. If you want to know more about fibreglass roofing, take a closer look around Gee GRP’s website or get in touch.

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