Your roof is the first line of defense for your home. While shingles get the most attention, the underlayment beneath them protects against the elements. If you aim to save time and money on your next roofing project, selecting the proper underlayment makes a significant difference. This guide will explore the different roof underlayments—including pros and cons—to help you make an informed choice for your next roofing project.
What Is Roof Underlayment?
Roof underlayment is a protective layer installed directly onto the roof deck. Shingles are applied directly on to the underlayment and function as a barrier against water.
Roofs can have one of three types of underlayment—asphalt-saturated felt, rubberized asphalt, or non-bitumen synthetic. Each type has benefits and drawbacks.
Types of Roof Underlayment
Knowing the different types of roof underlayment helps you choose the best option for your home. All underlayments aim to extend the lives of roofs by preventing excess moisture from seeping past.
Asphalt-Saturated Felt
Asphalt-saturated felt, commonly known as tar paper, is a traditional choice for roofing underlayment. This material is made from an organic base mat saturated with asphalt, offering several benefits.
Pros of Asphalt-Saturated Felt
Asphalt-saturated felt provides a layer of protection from rain if shingles are compromised, helping to shield a home from potential leaks. It also serves as a barrier between asphalt shingles and the plywood below, protecting shingles from any resins that may seep out of the wood. For homeowners on a budget, asphalt-saturated felt is a cost-effective option.
Cons of Asphalt-Saturated Felt
Asphalt-saturated felt lacks UV resistance, so you must cover it quickly after installation to avoid damage from sunlight. This material can tear easily during installation, making the process more challenging and potentially leading to future issues. Compared to other underlayment options, asphalt-saturated felt also has a shorter lifespan, meaning it may need replacement sooner if durability is a top priority.
Top Manufacturers of Asphalt-Saturated Felt
Atlas Roofing and Gardner Coatings are leading producers of high-quality asphalt-saturated felt. For instance, Atlas Roofing’s Gorilla Guard incorporates additives and glass fibers to outperform typical felt underlayments.
Rubberized Asphalt
Despite its name, rubberized asphalt underlayment contains little to no asphalt. It’s a more modern option with enhanced waterproofing.
Pros of Rubberized Asphalt
Rubberized asphalt offers solid advantages for roofing projects. It provides outstanding waterproofing, effectively protecting your home from moisture. With its resistance to UV rays, rubberized asphalt can handle prolonged sun exposure without degrading, making it a reliable choice for durability. This material also comes in different options, including fire-resistant properties.
Cons of Rubberized Asphalt
Rubberized asphalt costs more than traditional felt, making it less appealing for those on a tight budget. Installation often requires professional expertise, adding to the overall expense of a roofing project. The seams between rolls can create weak points that need extra attention to maintain a fully sealed surface.
Top Manufacturers of Rubberized Asphalt
Grace Select and MB Technology are renowned for their rubberized asphalt underlayments. Grace Select’s products feature a unique composition that meets industry standards for fastener sealability, usually reserved for much thicker materials.
Non-Bitumen Synthetic
Contractors often prefer non-bitumen synthetic underlayment, which manufacturers create from polymers like polyethylene or polypropylene. This lightweight and durable option has gained popularity in the industry.
Pros of Non-Bitumen Synthetic
Non-bitumen synthetic underlayment offers several substantial advantages. It’s highly durable, giving roofs long-lasting protection. Its lightweight design makes installation straightforward, reducing labor time, effort, and costs. The material also resists fungal growth, making it a sound choice for damp or shaded environments. It also resists water, protecting against leaks and ice dams that damage a roof.
Cons of Non-Bitumen Synthetic
Non-bitumen synthetic underlayment can come at a higher cost than traditional felt, which might impact budget-conscious projects. Certain types of this material can become slippery when wet, making installation more challenging, especially in damp or rainy conditions.
Top Manufacturers of Non-Bitumen Synthetic
Epilay and Owens Corning are leading producers of non-bitumen synthetic underlayments. Epilay’s products are known for their innovative features and lightweight design, while Owens Corning offers underlayments with high tear strength and improved walkability.
Factors To Consider When Choosing Roof Underlayment
Selecting the right roof underlayment involves balancing various factors. Here are important considerations.
Climate and Weather Conditions
The local weather plays an important role in underlayment selection. Areas that experience high winds, heavy rain, or ice dams may require more robust underlayment options. Understanding how conditions affect your roofing requirements can guide you toward the right choice.
Roof Pitch and Design
The slope of the roof and its design impact underlayment choice. Steeper roofs benefit from more slip-resistant options, while low-slope roofs might require enhanced waterproofing. The underlayment selection should match your home’s architectural characteristics, maximizing design appeal and performance.
Budget Constraints
While choosing the cheapest option is tempting, investing in quality underlayment saves money in the long run by preventing costly water damage and extending the roof’s lifespan. Evaluating the long-term benefits against immediate costs helps you make an informed financial decision.
Installation Tips for Roof Underlayment
Proper installation maximizes the effectiveness of roof underlayment. Here are tips for homeowners tackling this DIY project:
- Ensure the roof deck is clean and dry. Clear any protruding nails or debris.
- Start at the roof’s lowest point and work upward, overlapping each course.
- Use proper fasteners and follow manufacturer guidelines for spacing.
- Pay special attention to areas around chimneys, vents, and valleys.
- Ventilate fully to prevent moisture buildup.
Following these guidelines helps you achieve a smooth installation process while protecting your roof from issues caused by improper handling. When you pay attention to the details, you can tackle any challenges during installation.
Maintenance and Longevity
I recommend conducting regular inspections to maintain roof underlayment. After severe weather, check for damage or wear. Address any issues promptly to prevent water infiltration. Scheduling professional inspections every few years also helps catch potential problems early. By staying on top of maintenance, quality underlayment can last as long as the roofing material above it.
Environmental Considerations
You might worry about the ecological impact of various underlayment options. Some manufacturers create synthetic underlayments from recycled materials that you can use again at the end of their life cycle. Certain underlayments reflect heat and lower cooling costs, making your home more energy efficient. Choosing materials you value can support the environment while enjoying long-term energy savings.
Cost Comparison
The cost of roof underlayment varies significantly based on type and quality. Here’s a general price comparison, according to Angi*:
- Asphalt-saturated felt: $5 to $55 per square foot
- Rubberized asphalt: $50 to $75 per square foot
- Non-bitumen synthetic: $18 to $60 per square foot
While synthetic options have a higher up-front cost, their durability and performance offer better long-term value for many homeowners. Evaluating the connection between costs and benefits helps you find the most cost-effective option for your specific situation.
*We sourced costs for this article from contractor estimates used by Angi.
Final Thoughts About Roof Underlayment
Choosing the best roof underlayment is a decision that affects how your roof performs and how long it will last. Traditional asphalt-saturated felt is a practical choice for those on a budget, but rubberized asphalt and non-bitumen synthetic underlayments provide improved protection against severe weather. These advanced options come with features that enhance their durability. If you’re considering more robust roof underlayment solutions, these options deserve your attention.
Consider your local climate and budget when selecting an underlayment. Invest in high-quality materials and install them properly because they protect your home from water damage. The right underlayment is an investment in your home’s future.
