When installing a pitched roof, the right roofing felt is crucial for ensuring long-term durability and protection. Roofing felt serves as an underlayment beneath roof tiles or slates, acting as a secondary barrier against water ingress and weather conditions.
1. Traditional Bitumen Felt
Historically, bitumen-based roofing felt was the go-to choice for pitched roofs. Better known as "Sarking" felt, it consists of layers of asphalt-saturated paper or fiberglass, providing excellent waterproofing.
However with time it became evident that this type of felt was susceptible to deterioration, especially with temperature fluctuations. Another defect was its inability to allow the roof space to breathe - which has resulted in damp issues and shorter life spans for thousands of roofs across the country.
2. Modern Breathable Membranes
In recent years, breathable membranes have become the preferred choice for pitched roofs due to their superior performance. These synthetic materials are designed to allow moisture vapor to escape from inside the roof, preventing condensation buildup, while simultaneously keeping water out.
Breathable roofing felts are made from layers of polypropylene or polyester, making them highly durable and resistant to UV damage. They are lightweight and easier to handle compared to bitumen felt, which helps during installation. The breathable nature of these membranes ensures that your roof remains well-ventilated, reducing the risk of mold or rot in the roofing structure.
Key advantages of breathable membranes include:
- High vapor permeability, allowing moisture to escape
- Waterproofing capabilities to protect against external elements
- Longevity, with high resistance to weathering
5. Factors to Consider About Felt On a Pitched Roof
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Ventilation: Inserting adequate ventilation is essential for non-breathable membranes, like Sarking felt, to avoid condensation buildup inside the roof space.
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Local Building Regulations: Modern breathable membranes comply with Building Regulations. If you are not renewing the roof then ventilation tiles are adequate to improve the ventilation in the roof space.
6. Conclusion: Which Felt Should You Use?
For modern pitched roofs, breathable membranes provide excellent water resistance and vapor permeability. They help protect your roof from the elements while allowing moisture to escape, preventing issues like condensation or mold. However, in certain cases where sarking felt has already been used, ventilation can be restored by way of ventilation tiles.
Ultimately, there are solutions to which NSOA Roofing is happy to assist you find. Our expertise with ventilation will help you protect your home in a cost effective and efficient manner.
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