When it comes to installing or replacing a metal roof, ensuring proper underlayment is crucial. Underlayment acts as a protective layer between the metal roof panels and the roof deck, providing added insulation, moisture resistance, and protection against potential damage. One commonly used material for underlayment is roofing felt, also known as roofing paper or tar paper. In this article, we will explore whether roofing felt is a suitable choice for underlayment when installing a metal roof.
Understanding Roofing Felt
Roofing felt is a heavy-duty material made from a combination of petroleum-based products and cellulose fibers. It is typically manufactured in rolls and is available in different thicknesses. Roofing felt is commonly used in residential and commercial roofing projects as a temporary or permanent underlayment material.
Benefits of Using Roofing Felt as Underlayment
- Moisture protection: One of the significant advantages of roofing felt is its ability to provide a moisture barrier. It helps prevent water from penetrating the roof deck, protecting it from potential damage caused by leaks.
- Enhanced insulation: Roofing felt also acts as an extra layer of insulation, reducing heat transfer and potentially improving energy efficiency. This can be particularly beneficial in hot climates where maintaining a cooler interior environment is crucial.
- Improved noise reduction: The sound of rain, hail, or other external disturbances hitting a metal roof can often be quite loud. Roofing felt can help reduce the noise level, making the interior space more comfortable and peaceful.
Drawbacks of Using Roofing Felt as Underlayment
- Limited breathability: Roofing felt, especially the traditional asphalt-saturated type, has relatively low breathability. This means that it may trap moisture between the metal roof and the underlayment, potentially leading to mold, rot, or other moisture-related issues.
- Durability concerns: Compared to specialized underlayment materials designed specifically for metal roofing, roofing felt may not offer the same level of durability. While it can provide adequate protection in moderate climates, it may not withstand extreme weather conditions or provide long-term performance.
- Compatibility issues: Some types of metal roofs, such as standing seam roofs, may require specific underlayment materials that are tailored to suit the unique requirements of the roofing system. In these cases, using roofing felt as underlayment may not be recommended or compatible.
Alternatives to Roofing Felt for Metal Roofing Underlayment
- Synthetic underlayment: Synthetic underlayment materials, such as synthetic rubber or polypropylene, offer superior breathability, durability, and resistance to mold and rot. These materials are specifically designed to work well with different types of metal roofing systems.
- Self-adhering underlayment: Self-adhering membranes, such as peel-and-stick underlayment, provide a hassle-free installation process. They offer strong wind protection and enhanced waterproofing capabilities, making them suitable for areas prone to heavy rain or wind.
- Ice and water shield: In regions with harsh winters and ice dams, using an ice and water shield as underlayment can offer added protection against leaks caused by ice buildup. It provides a watertight seal around roof penetrations, such as vents and chimneys.
While roofing felt can provide some level of protection and insulation when used as underlayment for metal roofing, it may not be the best choice for all situations. It is important to consider factors such as climate, roof design, and compatibility with the specific metal roofing system. Consulting with a professional roofing contractor can help determine the most suitable underlayment material for a metal roof installation that ensures long-term durability and performance.