When it comes to roofing, one of the most critical components that often goes unnoticed is the underlayment. Specifically, the use of felt paper, also known as tar paper or roofing felt, has been a longstanding practice in the roofing industry. The question of whether you should put felt under shingles is a topic of discussion among homeowners, builders, and roofing professionals. In this article, we will delve into the world of roofing underlayment, exploring the benefits, drawbacks, and best practices of using felt under shingles.
Introduction to Roofing Underlayment
Roofing underlayment is a layer of material installed between the roof deck and the roofing material, such as shingles, tiles, or metal. Its primary purpose is to provide a barrier against water infiltration, protect the roof deck from damage, and ensure a smooth installation process. There are various types of underlayment materials available, including felt paper, synthetic underlayment, and ice and water shield. Each type has its unique characteristics, advantages, and disadvantages.
History of Felt Paper in Roofing
Felt paper, made from a combination of paper and asphalt, has been used in roofing for over a century. Its widespread adoption can be attributed to its affordability, ease of installation, and effectiveness in preventing water penetration. Traditionally, felt paper was installed in a single layer, with overlaps of 6-12 inches, to ensure a watertight seal. However, with the advancement of technology and the development of new materials, the role of felt paper in modern roofing has evolved.
Benefits of Using Felt Under Shingles
There are several benefits to using felt under shingles, including:
– Water Resistance: Felt paper provides an additional layer of protection against water infiltration, reducing the risk of damage to the roof deck and underlying structures.
– UV Protection: Felt paper helps shield the roof deck from ultraviolet (UV) radiation, which can cause degradation and damage to the wood.
– Fire Resistance: Felt paper can help slow the spread of fire, providing a critical barrier between the roof deck and the roofing material.
– Cost-Effectiveness: Felt paper is generally less expensive than other underlayment materials, making it a popular choice among builders and homeowners.
Drawbacks and Limitations of Felt Paper
While felt paper has been a staple in the roofing industry, it also has some significant drawbacks and limitations. These include:
– Permeability: Felt paper is not completely impermeable to water, and prolonged exposure to moisture can lead to degradation and failure.
– Installation Challenges: Felt paper can be difficult to install, particularly in windy or wet conditions, which can compromise its effectiveness.
– Limited Durability: Felt paper has a relatively short lifespan, typically ranging from 20 to 30 years, depending on the quality and installation.
Alternatives to Felt Paper
In recent years, alternative underlayment materials have gained popularity, offering improved performance, durability, and ease of installation. Some of these alternatives include:
– Synthetic Underlayment: Made from polypropylene or polyethylene, synthetic underlayment is more durable, resistant to wrinkles, and easier to install than felt paper.
– Ice and Water Shield: A self-adhering underlayment, ice and water shield provides superior protection against water infiltration and is ideal for use in valleys, skylights, and other vulnerable areas.
Best Practices for Installing Felt Under Shingles
If you decide to use felt under shingles, it is essential to follow best practices to ensure a successful installation. These include:
– Proper Overlap: Ensure that the felt paper overlaps by at least 6-12 inches to maintain a watertight seal.
– Tight Sealing: Use a suitable adhesive or fastening system to secure the felt paper to the roof deck, preventing wrinkles and air pockets.
– Adequate Ventilation: Ensure that the roof has adequate ventilation to prevent moisture buildup and reduce the risk of felt paper degradation.
Conclusion
In conclusion, the decision to put felt under shingles depends on various factors, including the type of roofing material, climate, and personal preference. While felt paper has been a traditional choice for roofing underlayment, its limitations and drawbacks must be considered. Alternative materials, such as synthetic underlayment and ice and water shield, offer improved performance and durability. By understanding the benefits and limitations of felt paper and following best practices for installation, homeowners and builders can make informed decisions about their roofing underlayment needs. Ultimately, a well-designed and properly installed roofing system, including a suitable underlayment, is crucial for ensuring the longevity and integrity of a building.
| Underlayment Material | Benefits | Drawbacks |
|---|---|---|
| Felt Paper | Water resistance, UV protection, fire resistance, cost-effectiveness | Permeability, installation challenges, limited durability |
| Synthetic Underlayment | Improved durability, resistance to wrinkles, ease of installation | Higher cost, potential for damage during installation |
| Ice and Water Shield | Superior water resistance, self-adhering, ideal for vulnerable areas | Higher cost, limited availability |
- Always follow the manufacturer’s instructions for the specific underlayment material being used.
- Ensure that the roof deck is clean, dry, and free of debris before installing the underlayment.
By considering the factors outlined in this article and selecting the appropriate underlayment material, you can ensure a successful roofing installation that provides long-term protection and durability for your building.
What is the purpose of felt under shingles?
The primary purpose of felt under shingles is to provide a layer of protection between the shingles and the roof deck. This layer, also known as roofing underlayment, helps to prevent water from seeping into the roof deck and causing damage. Felt paper, typically made from a combination of asphalt and fiberglass, is designed to be waterproof, allowing it to effectively shield the roof deck from moisture. By installing felt under shingles, homeowners can help to extend the lifespan of their roof and reduce the risk of costly repairs.
In addition to its waterproofing capabilities, felt under shingles also provides a smooth surface for the shingles to be installed on. This helps to ensure that the shingles lie flat and even, which is essential for maintaining their integrity and preventing damage. Furthermore, felt under shingles can help to reduce the risk of ice dams forming on the roof, which can cause significant damage to the roof and surrounding structures. By installing felt under shingles, homeowners can enjoy a more durable and long-lasting roof that requires less maintenance and repair over time.
What are the benefits of using felt under shingles?
The benefits of using felt under shingles are numerous and well-documented. One of the most significant advantages is the added layer of protection it provides against water damage. By preventing water from seeping into the roof deck, felt under shingles can help to prevent rot, mold, and mildew from forming, which can weaken the roof’s structure and lead to costly repairs. Additionally, felt under shingles can help to reduce the risk of ice dams forming on the roof, which can cause significant damage to the roof and surrounding structures.
Another benefit of using felt under shingles is that it can help to improve the overall performance and longevity of the roof. By providing a smooth surface for the shingles to be installed on, felt under shingles can help to ensure that the shingles lie flat and even, which is essential for maintaining their integrity and preventing damage. Furthermore, felt under shingles can help to reduce the risk of shingle blow-off, which can occur when high winds cause the shingles to lift and separate from the roof. By installing felt under shingles, homeowners can enjoy a more durable and long-lasting roof that requires less maintenance and repair over time.
Can I install shingles without felt underlayment?
While it is technically possible to install shingles without felt underlayment, it is not recommended. Felt underlayment provides a critical layer of protection against water damage and helps to ensure that the shingles are installed smoothly and evenly. Without felt underlayment, the shingles may be more prone to damage and the roof deck may be more susceptible to water intrusion. Additionally, many roofing manufacturers require the use of felt underlayment in order to validate the warranty on their products.
Installing shingles without felt underlayment can also lead to a range of other problems, including reduced roof performance and longevity. Without the added layer of protection provided by felt underlayment, the roof may be more prone to ice dams, shingle blow-off, and other forms of damage. Furthermore, installing shingles without felt underlayment can also void the warranty on the roofing materials, leaving homeowners with significant financial exposure in the event of a problem. For these reasons, it is generally recommended that homeowners install felt underlayment as part of their roofing system.
What types of felt underlayment are available?
There are several types of felt underlayment available, each with its own unique characteristics and benefits. The most common type of felt underlayment is asphalt-saturated felt paper, which is made from a combination of asphalt and fiberglass. This type of felt underlayment is relatively inexpensive and provides a good balance of waterproofing and durability. Another type of felt underlayment is synthetic underlayment, which is made from a combination of plastics and other materials. This type of underlayment is more durable and resistant to tears and punctures than asphalt-saturated felt paper.
In addition to these two types of felt underlayment, there are also several specialty products available, including rubberized asphalt underlayment and self-adhering underlayment. These products are designed to provide additional benefits, such as improved waterproofing and easier installation. When selecting a type of felt underlayment, homeowners should consider factors such as climate, budget, and personal preference. It is also a good idea to consult with a professional roofing contractor, who can provide guidance and recommendations based on their experience and expertise.
How do I install felt under shingles?
Installing felt under shingles is a relatively straightforward process that can be completed by a professional roofing contractor or experienced DIYer. The first step is to prepare the roof deck, which involves cleaning and inspecting the surface to ensure that it is free from debris and defects. Next, the felt underlayment is rolled out and installed, starting at the bottom edge of the roof and working upwards. The felt underlayment should be overlapped by at least 6 inches to ensure a watertight seal, and it should be fastened to the roof deck using roofing nails or staples.
Once the felt underlayment is installed, the shingles can be applied on top, following the manufacturer’s instructions and recommendations. It is essential to ensure that the felt underlayment is smooth and even, and that the shingles are installed in a way that prevents water from seeping underneath. Additionally, the felt underlayment should be installed in a way that allows for proper ventilation and drainage, which can help to prevent the formation of ice dams and other forms of damage. By following these steps and taking the necessary precautions, homeowners can ensure that their felt underlayment is installed correctly and provides long-lasting protection for their roof.
What are the common mistakes to avoid when installing felt under shingles?
There are several common mistakes to avoid when installing felt under shingles, including improper overlap, insufficient fastening, and incorrect installation of the felt underlayment. One of the most common mistakes is to fail to overlap the felt underlayment by at least 6 inches, which can create a gap that allows water to seep underneath. Another mistake is to use too few fasteners, which can cause the felt underlayment to lift and separate from the roof deck. Additionally, installing the felt underlayment in the wrong direction or with the wrong side facing up can also compromise its performance and effectiveness.
To avoid these mistakes, it is essential to follow the manufacturer’s instructions and recommendations, as well as to consult with a professional roofing contractor if necessary. Homeowners should also ensure that the felt underlayment is installed in a way that allows for proper ventilation and drainage, and that the shingles are installed on top in a way that prevents water from seeping underneath. By taking the necessary precautions and avoiding common mistakes, homeowners can ensure that their felt underlayment is installed correctly and provides long-lasting protection for their roof. Regular inspections and maintenance can also help to identify and address any issues before they become major problems.
How long does felt underlayment last?
The lifespan of felt underlayment can vary depending on several factors, including the type and quality of the underlayment, the climate and weather conditions, and the level of maintenance and upkeep. On average, felt underlayment can last for 20 to 30 years or more, although it may need to be replaced sooner if it becomes damaged or compromised. The lifespan of felt underlayment can also be affected by the type of shingles used, as well as the overall condition and integrity of the roof.
To maximize the lifespan of felt underlayment, it is essential to ensure that it is installed correctly and that the roof is properly maintained and inspected regularly. This can include tasks such as cleaning the gutters and downspouts, inspecting the roof for damage and wear, and making repairs as needed. Additionally, homeowners can consider using higher-quality felt underlayment products, such as synthetic underlayment, which can provide longer-lasting protection and durability. By taking the necessary precautions and maintaining their roof regularly, homeowners can help to extend the lifespan of their felt underlayment and ensure that their roof remains safe and secure for years to come.