16 May The benefits of felt & fibreglass roofing

Felt and GRP fibreglass roofing systems are the most popular systems for flat roofs. They are also suitable for pitched roofs in some applications.

The popularity for both systems stems from different requirements, however. Felt is a cheaper material, fibreglass is more expensive. Felt typically lasts for less than 10 years, fibreglass lasts for over 20. So, there are key differences between them, although both have benefits which we will take a closer look at below.

Felt roofing systems

• Cheap
• Effective
• Easy to replace

Felt is traditionally a flat roofing system. It is impenetrable when installed correctly and viscous. It’s been used for over fifty years in the roofing industry, and although the membrane itself has changed slightly over the years, it largely remains a product made from bitumen (asphalt or coal-tar pitch).

The benefits of felt roofing for the consumer are its low cost and good performance. Roof felt is on average much cheaper than newer roofing systems, such as fibreglass, and offers performance that is comparable when installed properly. It’s also quick to install and can be replaced quickly if needs be.

The benefits of felt roofing for the roofer are its pliability and easy transportation. Felt is extremely pliable and easily manipulated which makes it easier to work with. Felt is rolled up in transport which means a van is often all that’s needed to get the job done.

The downside to roofing felt is its lifespan. Typical roofing felt will last for 5-8 years, depending on the weather it experiences.

Did you know?

Did you know that today’s roof felts typically have a 3-layer membrane system? The new 3-layer membrane system is far superior to the bitumen and stone chip system of old. It uses a system of underlay, waterproof membrane and polyester to offer a perfect finish and excellent waterproofing performance.

Fibreglass roofing systems

• Durable
• Excellent longevity
• High performance

Fibreglass is a newer roofing system that lends itself best to flat roofing but is also suitable for pitched roofs in some applications. Fibreglass is much more durable than felt and stronger too. It has no seams, so it’s less likely to fail and let water in, and it’s relatively easy for a professional to repair if damaged.

The benefits of fibreglass roofing for the consumer are its durability, longevity and high performance. A fibreglass roof will last for more than 20 years and it’s less likely than felt to develop a fault. The fact it has no seams, and is also easy to repair, means that any issues can be quickly identified and nullified by a professional.

The primary benefit of fibreglass roofing for the roofer is that it’s prefabricated (it often comes pre-cut from the factory, allowing for quick installation). There’s also no wastage at all, which reduces the need to go to the local skip. This is also more environmentally friendly, since roof felt is not widely recycled.

The downside to fibreglass roofing is its cost. It typically costs 10 times more than felt, depending on the brand used.

Did you know?

Did you know that fibreglass roofing systems manufactured in the UK and Europe use corrosion resistant laminates and fire-retardant resins? High quality fibreglass is therefore one of the most heat and chemical resistant roof materials on the market. This makes it a prime candidate in applications where safety is a priority.

Which is the best material for my roof?

This is a matter of application.

Small outbuildings, such as single garages and porches, can make do with a felt roof. A felt roof is highly affordable and will give you the performance you need.

Larger outbuildings, such as double garages and converted workspaces, will be better served by a fibreglass roof because you’ll be using them more. Therefore, a more durable roofing material will serve you for longer.

In terms of comparison, both felt, and fibreglass, are equally waterproof. However, fibreglass is a stronger roof material. This makes it a better choice in areas that see intense rainfall and wind. So, for buildings that will experience severe weather, we recommend GRP or fibreglass roofing as the best roofing system.

It’s also important to note that some newer felt roof systems offer greater longevity than 5-8 years. Some systems come with a guarantee of at least 10 years. So, despite the durability of fibreglass, it isn’t necessarily a slam dunk in its favour. We recommend speaking to an experienced roofer for personalised advice about your project.