When it comes to roofing, choosing the right materials is crucial to ensuring the durability and longevity of your roof.

One such material is roofing felt, which is a layer of material that is applied underneath the shingles or tiles of a roof. Roofing felt, also known as tar paper, is a thin, flexible material that acts as a barrier against moisture, wind and other elements that can damage your roof.

The question is:

What is the best roof felt to use?

At Good Build Superstore, we’re here to help!

In this buyer’s guide, we’ll walk you through the different types of roofing felt, the materials they are made from, the pros and cons of roofing felt and much more!

Let’s crack on!


Table of contents:


Roof felt types

Torch-on roofing felt, self-adhesive felt and shed felt are all roofing materials that are commonly used in the construction industry.

Let’s take a closer look at what makes each one of them stand out.

Torch-on roofing felt

IKO torch-on roofing felt

Torch-on roofing felt is applied using a propane torch to melt the bitumen backing of the felt, which then bonds to the roof surface. It’s made from a polyester or fibreglass base, which is coated with a layer of bitumen.

Torch-on roofing felt is durable, weather-resistant, and can last up to 25 years if installed correctly. It is commonly used in flat or low-pitched roofs.

Self-adhesive felt

Coldseal self-adhesive roofing felt

Self-adhesive felt, also known as peel-and-stick felt, is a roofing material that comes with self-adhesive backing. It is made of the same materials as torch-on roofing felt, but it does not require a propane torch to install.

Self-adhesive felt is easy to install, making it a popular choice for DIY enthusiasts. It is also lightweight, so it is suitable for shed roofs or other lightweight structures.

Shed felt

Shed felt kit

Shed felt is a type of roofing material that is commonly used in the construction of garden sheds and other small structures. It is typically made of a paper or fibreglass base, which is coated with a layer of bitumen.

Shed felt is available in a range of grades and thicknesses, making it suitable for a variety of applications. It is also easy to install, which is why it is a popular choice for DIY enthusiasts.


Materials

Roofing felt can be either organic or synthetic. Organic roofing felt is made from recycled paper and asphalt, while synthetic roofing felt is made from fibreglass or polyester and asphalt.

Organic roofing felt

Organic roofing felt is made from a base of recycled paper or other natural materials that are soaked in asphalt to make them waterproof. The main advantage of organic roofing felt is that it is biodegradable and environmentally friendly.

However, organic roofing felt is more prone to wear and tear over time than synthetic roofing felt.

Synthetic roofing felt

Synthetic roofing felt is made from fibreglass or polyester and asphalt. This type of roofing felt is more durable than organic roofing felt and can withstand harsh weather conditions better. Synthetic roofing felt is also more resistant to mould and mildew than organic roofing felt.


What is the difference between felt 15 and 30?

The most common types of roofing felt used in the UK are often referred to as 15 and 30 felt.

Here’s how they differ from each other:

15 felt, also known as Type 1F or BS 747:2000 Type 1F, has a weight of approximately 15kg per 10 square metres (1.5kg per square metre). It is a lighter-weight underlayment material typically used in roofing applications where the slope of the roof is steep, such as in residential construction.

30 felt, also known as Type 3B or BS 747:2000 Type 3B, has a weight of approximately 30kg per 10 square metres (3kg per square metre). It is a heavier-weight underlayment material typically used in roofing applications where the slope of the roof is lower, such as in commercial construction.

The main difference between 15kg and 30kg felt is their weight and thickness. 30kg felt is thicker and more durable than 15kg felt, which makes it better suited for use in areas with high foot traffic or where there may be a risk of damage to the roofing material. However, 15kg felt may be sufficient for many residential roofing applications where the slope of the roof is steep and there is little foot traffic.


Advantages and disadvantages of roofing felt

Flat roof felt

Overall, roofing felt can be a cost-effective and useful material for many roofing applications, but its suitability will depend on a variety of factors, including the climate, intended use and budget for the project.

Advantages

Water-resistant – Roofing felt is designed to be water-resistant, which helps to protect the roof from water damage.

Added protection – Roofing felt acts as an extra layer of protection between the roof decking and the shingles or other roofing materials.

Improved lifespan – When properly installed, roofing felt can help to extend the lifespan of a roof by providing an additional layer of protection against the elements.

Easy installation – Roofing felt is relatively easy to install, which can help to reduce the time and labour costs associated with roofing projects.

Cost-effective – Roofing felt is generally less expensive than other roofing materials, which makes it a popular choice for many roofing applications.

Disadvantages

Not suitable for all climates – In areas with extreme temperatures or high levels of moisture, roofing felt may not provide adequate protection against the elements.

Vulnerable to damage – Roofing felt can be vulnerable to damage from foot traffic or other sources, which can compromise its effectiveness as a protective layer.

Prone to wrinkling – When not installed correctly, roofing felt can become wrinkled or distorted, which can impact its ability to provide proper protection.

Environmental concerns – Some types of roofing felt contain asphalt or other materials that can be harmful to the environment, which may make them less desirable for environmentally conscious builders and homeowners.


Final thoughts

Roofing felt is a well-established and reasonably priced option for ensuring that your roof remains waterproof, with a proven track record of durability.

Its straightforward installation process has made it a popular choice for those who wish to complete the installation themselves.

What’s more:

There is a wide range of roofing felt options available on the market, so you can find the best roof felt for your specific needs without difficulty.

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