Felt roofing is a common and practical choice in the UK, especially for flat roofs on homes, garages, and sheds. It’s popular because it’s both affordable and easy to install. With proper maintenance, felt roofing can last around 10 years, offering reliable protection from the elements. Though it may require occasional upkeep, this ensures your roof stays in good condition, preventing weather-related issues like cracking or warping.
Understanding how to care for your roofing membrane is essential for keeping your home safe and extending the roof’s lifespan. In this article, we’ll explore the types of roofing felt, their benefits, and what factors influence the cost of refelting, giving you the knowledge to make smart decisions for your property.
Key Takeaways
- Roofing felt is essential for securing tiles and protecting against weather damage.
- The lifespan of roofing felt varies depending on the material, ranging from 15 to 50 years.
- Costs for refelting a roof can vary significantly based on size, condition, and material choice.
- Alternatives to traditional roofing felt include GRP and EPDM, offering different benefits.
- Professional installation is recommended to ensure durability and effectiveness.
What is Roofing Felt?
Roofing felt, also known as underlay, is an essential layer when it comes to roofing supplies for a new roof. It is usually placed beneath tiles or slate and helps secure the roofing in place. Felt provides stability, and supports the locking systems between planks. It also reduces noise and allows the flooring to “float,” ensuring added sturdiness.
Primarily, roofing felt stabilises tiles, especially during winds or storms, and protects against rain, preventing leaks and water damage. This roofing material also helps insulate your home by retaining warmth during the colder months, reducing the need for constant heating and helping to lower energy costs.
Advantages of Using Roofing Felt
- Proven Reliability: Roofing felt is a well-established material, commonly used in both residential and commercial roofing projects.
- Effective Waterproofing: Its effectiveness in waterproofing roofs has been demonstrated over many years.
- Cost-Effective: Felt is an affordable option that offers excellent value for money.
- Quick Installation: It can be installed relatively quickly.
- Long Lifespan: Roofing felt can last over 25 years.
- Strong Warranties: Manufacturers often offer warranties ranging from 20 to 30 years.
- Easy to Repair: Repairs are straightforward if needed.
- Fire Protection: Using a fire-rated top layer can provide a good level of fire resistance.
- Durable in Harsh Conditions: It can withstand ponding water and is resistant to UV rays, strong winds, and rain.
Types of Roofing Felt
- Asphalt Saturated Felt
Asphalt-saturated felt is a common type of roofing felt. It is made by soaking a base material—usually organic or fibreglass—in asphalt. This type typically lasts about 15-20 years. While it is affordable and easy to install, it is not as durable as some newer options. It can tear easily, especially during installation or in bad weather, and may wear out more quickly when exposed to UV light or moisture. - Fibreglass roofing Felt
Fibreglass roofing felt is a stronger version of asphalt-saturated felt, using fibreglass as the base material. This type lasts longer, usually between 20-30 years, and offers better fire and tear resistance. Its improved durability makes it a great choice for projects needing a longer-lasting material. - Synthetic Roofing Felt
Synthetic roofing felt is made from materials like polyethylene and offers a modern alternative to traditional options. With a lifespan of 25-40 years, it is very durable. Synthetic felt resists tearing, water, and UV rays well, making it ideal for roofs in harsh weather. Its lightweight nature also makes it easy to handle, making it a popular choice for long-term roofing solutions. - Rubberised Asphalt Roofing Felt
Rubberised asphalt roofing felt combines rubber and asphalt for high performance. It can last anywhere from 30-50 years, thanks to its excellent waterproofing and self-sealing properties that help prevent leaks. This type is very durable and is especially useful in areas with extreme weather. - Bitumen Roofing Felt
Bitumen roofing felt is similar to asphalt-saturated felt but has a coating of bitumen, which can be either oxidised or modified. It typically lasts between 20-35 years and is very resistant to water, UV rays, and temperature changes. The modified versions offer extra flexibility and longevity, making this type a strong option for durable roofing.
Estimating the Lifespan of Roof Felt
The lifespan of your roof felt largely depends on the type of tiles used, as they come in various styles and textures. Traditional roof felt under tiles can last around 30 years, depending on the conditions it is exposed to, as it is not as durable as granite. In contrast, modern roofing materials may not last as long due to a decrease in quality. Although they tend to be more durable, they can also be more expensive than in the past.
When replacing roof underlay, opt for a more breathable option. Breathable roofing underlay works better with traditional materials and is a superior replacement for felt. Using the wrong type of felt increases the risk of condensation, which can damage your home and lead to higher costs. If the air in the roof space is warm and contains moisture, the roof can become cold during the winter months, causing water to condense on the underside of the roof.
How to Tell if Your Roofing Felt Needs Replacement
If your roofing felt becomes damaged or broken, it will require repair or replacement, as it will no longer provide adequate protection and may lead to a cold, musty environment. One of the most common reasons for replacing roofing felt is leakage. If your house experiences significant leaks after heavy rainfall, this is a clear indication that it needs to be replaced.
Another sign to watch for is if your tiles are shifting or becoming dislodged more easily. This may indicate that the tiles are no longer securely fastened underneath the felt, and replacement is necessary to prevent potential hazards. Additionally, if there is leaking or condensation seeping through, it can negatively impact your health by clogging airways and causing other health issues.
Cost of Refelting a Roof
The cost of refelting a roof can vary quite a bit, depending on the size of the roof and its condition. Generally, felt roofing costs between £30 and £45 per square metre. For a medium-sized shed, you might spend around £250 to £450. Labour costs will also add to the total, usually around £200 per day.
For those needing to replace a flat felt roof, the costs are different. Refelting an average-sized flat roof garage costs a ballpark of around £1,500.
If you need to replace the roofing felt under tiles, it’s important to assess how much of the existing felt requires replacement. For a small patch, the cost can be as low as £200, which covers about 4m². However, if the damage is extensive and the entire roof needs refelting, the cost will be significantly higher. On average, refelting an entire roof under tiles can cost around £4,800, though this can vary depending on the roof size, the type of tiles, and the other factors mentioned earlier.
Alternative Options to Roof Felt
While felt roofing is a reliable choice for flat roofs, there are several other alternatives available. Two popular options in the market are GRP (glass reinforced plastic) and EPDM (rubber roofing)On the other hand, EPDM rubber roofing boasts an impressive lifespan of approximately 50 years. It effectively repels moisture and offers an attractive appearance. However, its installation can be complex and. GRP has gained significant traction in the UK, but it generally has a lifespan of around 20-25 years and can be up to £30 per metre more expensive than traditional roofing felt.
usually requires the expertise of a roofing professional. For those considering a DIY approach, self-adhesive grey roof felt is a more affordable and simpler alternative to install.
Conclusion
Roofing felt is a reliable and cost-effective option for protecting your home’s roof, with different types offering various levels of durability and weather resistance. Whether you are refelting a roof or exploring alternative materials like GRP or EPDM, understanding the options available will help you make the best choice for your property. Regular inspections and timely replacements of roofing felt can prevent significant damage and extend the lifespan of your roof.
Frequently Asked Questions
How long does roofing felt typically last?
The lifespan of roofing felt depends on the type. Asphalt-saturated felt lasts around 15-20 years, fibreglass felt about 20-30 years, synthetic felt between 25-40 years, rubberised asphalt felt 30-50 years, and bitumen felt 20-35 years.
What are the signs that my roofing felt needs replacing?
Signs include leaks after heavy rain, dislodged or moving tiles, and visible damage or wear. If your roof underlay is causing condensation or dampness, it might be time for a replacement.
How much does it cost to refelt a roof?
The cost of refelting a roof varies depending on factors like the size and condition of the roof, the type of felt used, and accessibility. On average, costs range from £30-£45 per square metre, with full roof refelting potentially costing around £4,800.
Are there alternatives to traditional roofing felt?
Yes, alternatives include GRP (glass reinforced plastic) and EPDM (rubber roofing). These materials offer different benefits, such as longer lifespans and greater durability, though they may come with higher upfront costs.
Can I refelt my roof myself?
While it’s possible to refelt a roof as a DIY project, it is recommended to hire professionals. They have the expertise, tools, and materials needed to ensure the job is done correctly, preventing future issues with wind and water damage.
How can I determine the number of felt layers my roof requires?
The ideal number of felt layers depends on factors such as climate, roof slope, building usage, and manufacturer guidelines. It’s advisable to consult with roofing professionals before starting a project to receive tailored advice on the best layering strategy for your roof.
Are there UK regulations on the number of felt layers?
In the UK, building regulations don’t universally dictate the number of felt layers required. However, in Scotland and Northern Ireland, at least three layers are typically required for new commercial buildings. Local planning authorities may also have specific material requirements based on building codes or permits, so it’s essential to check the rules relevant to your area and project.
