What is flat felt roofing? [Infographic]

Posted on 17 March 2021

Flat felt roofing has been a popular choice for property owners for many years. Made from a combination of bitumen, sand, and fibrous membrane, it is a strong and robust roofing solution. Flat felt roofs benefit from a long lifespan of around 30 years or more. They’re also one of the most affordable options. So what is flat felt roofing? Read on to find out more about flat felt roofing.

What is flat felt roofing? [Infographic]

Flat felt – one of the top roofing solutions

Flat Roofs in Grimsby

Felt roofing is very common in the UK. Not only do flat felt roofs look appealing, but they’re also extremely durable, remaining resistant not just to moisture, but rips and movement too. Small metal fibres are used in the construction of felt roofs. This makes them stronger and even more hardwearing. They’re weatherproof, repelling heat as well as water. This is important as it helps to avoid potential issues such as leaks, water pooling, and deterioration of the roof. Modern felt roofs made with bitumen are able to contract and expand better. This ensures they don’t lose their elasticity as easily as felt roofs in older properties. As long as you hire experienced roofers in Grimsby or Louth to install your flat felt roof, there’s no reason why it shouldn’t last you 30 years or more.

What is roofing felt made from?

Bitumen is mixed with fibreglass or polyester to construct felt roofs. Polyester is tough and difficult to tear. This material also copes well with the usual movement related to flat roofs. The combination of polyester and modified bitumen ensures that felt roofing is tough and long-lasting. Whilst these two materials create a robust roof, a final layer is required to protect it from the elements. Very cold temperatures can impact a felt roof, but strong sunlight is even more harmful. It causes the oils to dry, causing it to become hard and brittle. Heat expansion movement can occur too. 

To provide valuable protection, we add a surface layer. There are various options to choose from for this layer, including lead flashings or even solar reflective paint. Often, we use a mineralised cap sheet to give a smart and easy to maintain finish.

More benefits of flat felt roofs

There are so many benefits to using felt for flat roofs. Not only does it consistently perform, offering aesthetic appeal as well as withstanding the effects of the elements, but it also offers fantastic value for money. Felt is one of the most low-cost roofing solutions, making it a popular option with cost-conscious homeowners. Flat felt roofs are generally easy to maintain too, meaning they’re unlikely to require many significant repairs. They tend to last between 20-30 years, however, we can often recycle them at the end of their lives. This makes them a very eco-friendly roofing choice.

When should a flat felt roof be replaced?

Flat Roofing Grimsby

A flat felt roof that’s been installed to a high standard by experienced roofers in Louth or Grimsby should last in the region of three decades. However, you shouldn’t always wait until the end of a roof’s expected lifespan to replace it. There are some big signs that a felt roof needs replacing, from weather damage to organic growth such as moss and algae.

Tears and cracks.

Often caused by weather damage or even simply due to age, tears and cracks can be easy to identify. Whilst smaller tears can often be fixed easily and affordably, larger splits across the surface of the roof are more serious, and could indicate it’s time to replace it. Failing to replace a roof with serious cracks could lead to water entering your home.

Bubbling and blistering.

This problem can sometimes arise in felt roofs if the adhesive fails. It’s often easily repairable. However, sometimes the blisters can become so large that there’s no option but to replace the roof. Blisters can occasionally pop, leaving a hole in the roof. So, if you do notice bubbling or blistering on your flat felt roof, it’s important to address the problem sooner rather than later. These issues can either be fixed by repairs or replacement.


The problem of ponding can seriously reduce the lifespan of a flat felt roof. Standing water causes stress to the roof, potentially leading to cracking and even water making its way into the home. If you do notice ponding on your roof, you need to call a local company specialising in roofing in Grimsby or Louth right away. They may be able to fix it, however, replacing the roof may be the only option if the problem has been going on for some time.

Organic growth.

You might not feel particularly worried when you spot moss or algae on your felt roof. However, it’s actually a sign of water retention and is often the result of not being maintained properly over time. If unaddressed, a build-up of organic growth can cause larger problems with water damage. In this case, we may need to completely replace the roof.

If you notice large tears and cracks, bubbling and blistering, ponding or organic growth on your flat felt roof, it may be time for it to be replaced. Although these roofs are relatively easy to install, in most cases, professional roofers in Grimsby will be required. We can install your new roof to the highest possible standards. 

Contact Raven Roofing and Repairs

Raven Roofing are on hand to assist, whether you’re looking for a flat felt roof replacement or you require repairs carried out to your existing felt roof. We’re one of the first-choice firms for roofing in Louth and Grimsby, building up a fantastic reputation throughout the region. To discuss your roofing needs with our team, call us on 01472 565 084 (Grimsby) or 01507 640 072 (Louth). You can also send us a message via the contact form on our website and we’ll get back to you right away.

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Fantastic professional and friendly service. Used Raven roofing for a full new roof. Very happy and extremely satisfied with the work that has been carried out. Would definitely use again and also highly recommend :)

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