In the world of roofing, there are components that, while not immediately visible, play a pivotal role in the overall performance and longevity of the roof. One such component is roofing felt, a material that serves as a critical underlayment in roofing systems. Often concealed beneath the outer layer of roofing shingles, roofing felt is a breathable, waterproof barrier that lies between the roof deck and the shingles, providing an essential layer of protection for the structure beneath.
Roofing felt, traditionally made from a base of natural materials like wood cellulose, is now predominantly manufactured using fiberglass or polyester fleece that is impregnated with bitumen. This evolution in materials has enhanced the durability and water-resistant properties of the felt, making it an even more effective component in roofing systems. The primary function of roofing felt is to serve as a secondary barrier against moisture. It helps to protect the roof deck from rain, snow, and ice, which can seep through the shingles due to wind-driven rain or melting snow. This barrier is crucial in preventing water damage and rot in the wooden structure of the roof deck, which can compromise the integrity of the entire roof if left unprotected.
Another important function of roofing felt is its role in providing a smooth, even surface on which to install shingles. This can be particularly important in re-roofing projects where the surface of the roof deck may be uneven or damaged. The layer of felt helps to ensure that the shingles lay flat and uniform, contributing to the aesthetic finish of the roof and its overall effectiveness in shedding water.
Roofing felt also offers additional protection during the construction phase. In the event of sudden weather changes, where a roofing project might be interrupted by rain, the felt provides temporary protection against water ingress, safeguarding the building’s interior and the roof structure until the project can be resumed.
The installation of roofing felt is a meticulous process that requires attention to detail. The sheets of felt are rolled out and secured to the roof deck, typically using roofing nails or staples. It is essential that the sheets overlap sufficiently to ensure a continuous, watertight layer. Care must be taken to avoid any gaps or wrinkles that could compromise the effectiveness of the felt as a moisture barrier.
There are different types of roofing felt available, varying in thickness and quality. The choice of felt usually depends on factors like the type of roofing shingles being used, the climate, and the specific needs of the building. In regions with high rainfall or snow, a heavier, more durable felt may be necessary. Similarly, in areas prone to high winds, a stronger felt that can withstand wind uplift is preferable.
In recent years, there has been a significant development in roofing underlayments with the introduction of synthetic products. These synthetic underlayments offer advantages over traditional felt, such as being lighter, stronger, and more resistant to tearing. They also tend to be more resistant to mold and rot, providing a longer lifespan. However, traditional bitumen-based felt continues to be widely used due to its proven track record and cost-effectiveness.
In conclusion, roofing felt is a fundamental component of a roofing system, offering a vital layer of protection against moisture and contributing to the longevity and durability of the roof. Its role, although largely unseen, is indispensable in ensuring the structural integrity of the roof and, by extension, the entire building. Whether in traditional bitumen-based forms or modern synthetic variants, roofing felt remains a key player in the complex and crucial world of roofing.