When it comes to protecting your home from the elements, roof underlayment is one of the most critical components of your roofing system. It serves as a barrier between your roof deck and shingles, providing an added layer of protection against moisture, wind, and temperature fluctuations. Choosing the right type of underlayment—whether felt, synthetic, or rubberized—can impact the longevity and durability of your roof. In this guide, we’ll compare the options, discuss their pros and cons, and help you make an informed choice. For professional installation and expert advice, explore our services in roofing windows and siding.
What Is Roof Underlayment and Why Is It Important?
Roof underlayment is a waterproof or water-resistant material installed directly onto the roof deck, beneath your shingles, tiles, or metal roofing. While shingles are the first line of defense against rain, wind, and debris, underlayment acts as a backup layer to:
- Prevent moisture from penetrating the roof deck.
- Protect the roof from leaks caused by ice dams, heavy rain, or wind-driven water.
- Provide temporary protection during the roofing installation process.
- Improve the overall performance and lifespan of the roofing system.
Choosing the right roof underlayment is essential to ensure your home remains protected, regardless of the climate or roofing materials you choose.
Types of Roof Underlayment: Felt, Synthetic, and Rubberized Options
When selecting roof underlayment, there are three main types to consider: felt underlayment, synthetic underlayment, and rubberized asphalt underlayment. Let’s compare their key features, benefits, and drawbacks.
1. Felt Roof Underlayment
Felt underlayment, also known as tar paper or asphalt-saturated felt, is the traditional choice for roofing projects. It is made by saturating a fiberglass or paper mat with asphalt, which makes it water-resistant.
Pros of Felt Underlayment:
- Affordable: Felt underlayment is one of the most cost-effective options available.
- Water Resistance: It provides a good level of protection against moisture for standard roofing projects.
- Readily Available: Widely used and available in two weights: 15-pound (lighter) and 30-pound (heavier).
Cons of Felt Underlayment:
- Shorter Lifespan: Felt underlayment is less durable compared to synthetic or rubberized options.
- Tears Easily: It can tear or wrinkle during installation, especially if exposed to moisture or high winds.
- Weight: Heavier felt can be difficult to handle during installation.
- Limited Waterproofing: While it is water-resistant, it is not fully waterproof.
Best For:
Budget-conscious homeowners or projects in areas with mild weather conditions.
2. Synthetic Roof Underlayment
Synthetic underlayment is made from polypropylene or polyethylene, offering a more durable, water-resistant, and lightweight alternative to traditional felt. It has become increasingly popular for modern roofing projects due to its enhanced performance.
Pros of Synthetic Underlayment:
- Exceptional Durability: Synthetic underlayment is tear-resistant and can withstand heavy foot traffic during installation.
- Water Resistance: Provides superior protection against water infiltration compared to felt.
- Lightweight: Easier to handle and install, reducing labor time and costs.
- UV Protection: Can remain exposed to sunlight for weeks without degrading.
- Mold and Mildew Resistant: Synthetic materials prevent moisture buildup that can lead to mold growth.
Cons of Synthetic Underlayment:
- Higher Cost: Synthetic underlayment is more expensive upfront compared to felt.
- Non-Biodegradable: Synthetic materials are not environmentally friendly.
Best For:
Homeowners looking for long-term durability, superior weather protection, and performance in extreme climates.
3. Rubberized Asphalt Roof Underlayment
Rubberized asphalt underlayment is a premium option made from a combination of asphalt and rubber polymers. It is fully waterproof and often features a peel-and-stick adhesive backing for a secure installation.
Pros of Rubberized Asphalt Underlayment:
- Waterproof: Provides complete waterproofing, making it ideal for areas prone to heavy rain or snow.
- Self-Sealing: The material seals around nails and fasteners, preventing leaks.
- Durability: Highly durable and resistant to extreme weather conditions, including ice dams and heavy winds.
- Versatile: Can be used under various roofing materials, including shingles, metal, and tile.
Cons of Rubberized Asphalt Underlayment:
- Higher Cost: Rubberized asphalt is the most expensive underlayment option.
- Heavy Weight: It is heavier and more difficult to install compared to synthetic options.
- Limited Availability: May not be as widely available as felt or synthetic options.
Best For:
Homes in areas with extreme weather, including heavy rain, snow, or ice dams. It’s also ideal for high-value roofing projects requiring premium protection.
Key Differences Between Felt, Synthetic, and Rubberized Underlayment
| Feature | Felt Underlayment | Synthetic Underlayment | Rubberized Asphalt |
| Cost | Affordable | Moderate | Premium |
| Durability | Moderate | High | Very High |
| Water Resistance | Water-Resistant | Water-Resistant | Fully Waterproof |
| Ease of Installation | Moderate (heavier material) | Easy (lightweight and tear-resistant) | Moderate (self-adhesive but heavy) |
| Weather Exposure | Limited | UV-resistant (weeks) | UV-resistant (longer exposure) |
| Best For | Mild climates | Extreme weather conditions | Heavy rain, snow, and ice |
How to Choose the Right Roof Underlayment
When selecting the best underlayment for your roof, consider the following factors:
- Climate: For regions with heavy rainfall, snow, or ice dams, rubberized asphalt is the most reliable option. For mild climates, felt or synthetic underlayment may suffice.
- Roofing Material: Some roofing materials, such as metal or slate, may require specific types of underlayment for maximum performance.
- Budget: If cost is a concern, felt underlayment is the most affordable option. However, investing in synthetic or rubberized options can provide long-term savings through durability and protection.
- Longevity: For homeowners planning to stay in their home long-term, synthetic or rubberized underlayment is the better investment.
Trust Boelter Is Better for Your Roofing Needs
At Boelter Is Better, we specialize in providing high-quality roofing solutions, including expert advice on roof underlayment. Whether you’re replacing an old roof or building a new one, our team can help you select the best materials to ensure your home stays protected. With our professional roofing, windows, and siding services, we deliver durability, value, and peace of mind for every project.
Final Thoughts
Choosing the right roof underlayment is crucial for protecting your home from the elements. While felt underlayment offers affordability, synthetic and rubberized asphalt options provide superior durability, weather resistance, and performance. By understanding the pros and cons of each type, you can make an informed decision that fits your budget, climate, and long-term goals.
Ready to upgrade your roof? Contact Boelter Is Better today to learn more about our professional roofing services and ensure your home has the protection it deserves!
