What is the Best Underlayment for Roofing? Discover Your Options

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Aug 7, 2023

When planning a roofing project, whether it’s a brand-new installation or a replacement job, your choice of underlayment is as crucial as the visible roofing materials themselves. But with the myriad of options available, you may be asking yourself, “What is the best underlayment for roofing?” This article seeks to demystify the complexities surrounding roofing underlayment and helps you make the right decision for your roofing project.

As a protective secondary layer, roofing underlayment acts as a barrier, enhancing your roof’s durability against the elements and providing extra insulation. It’s also a vital component in maintaining your roof’s integrity and extends the lifespan of your roofing system. Given its critical role, it’s crucial to choose the best underlayment for your particular needs.

There are three main types of roofing underlayment: asphalt-saturated felt, rubberized asphalt, and synthetic underlayment. Let’s delve into the details of each option.

Asphalt-Saturated Felt

For decades, asphalt-saturated felt has been the traditional choice for roofing underlayment. It’s made from either organic or fiberglass substrate, which is then saturated with asphalt to enhance water resistance. While it is less technologically advanced than other types of underlayment, its affordability and reasonable performance make it a popular choice among homeowners and contractors. It’s particularly effective in mild climates and when installed beneath heavy roofing materials like slate or tiles.

Rubberized Asphalt Underlayment

Rubberized asphalt underlayment is a premium choice that offers the best waterproofing capabilities. It consists of a layer of asphalt saturated with rubber polymers and added adhesive backing, which gives it a seal around the roofing fasteners, providing an airtight and waterproof barrier. This underlayment is typically more expensive than the others, but it’s ideal for roofs prone to severe weather conditions or those that need additional waterproofing, such as low-slope roofs.

Synthetic Underlayment

Compared to traditional asphalt-saturated felt, synthetic underlayment, made from polypropylene or polyester, is a high-performing and durable option. It’s less likely to tear, more water-resistant, and more resistant to fungus and UV damage. Additionally, synthetic underlayment is lighter and easier to install, making it a popular choice for contractors. While it is more expensive than asphalt-saturated felt, it offers superior performance and durability, making it a cost-effective option in the long run.

To choose the best underlayment for your roofing project, consider the following factors:

Roofing Material

Some underlayment materials work better with specific roofing materials. For example, asphalt-saturated felt is often paired with heavy roofing materials like slate or tiles.


If you live in an area prone to harsh weather conditions, a more robust underlayment like rubberized asphalt or synthetic material would be better suited.

Roof Slope

Low-slope or flat roofs often require a more water-resistant underlayment, such as rubberized asphalt.

Local Building Codes

Check your local building codes before selecting an underlayment. Some regions have specific requirements for fire resistance, wind resistance, or other factors.


While cost should not be the only deciding factor, it’s essential to balance performance and cost.

Installation Factors for Roofing Underlayment

The best underlayment for roofing isn’t just about the product itself, but also how well it’s installed. Factors like proper installation, adherence to local building codes, and the underlayment’s compatibility with the overlying shingles can all significantly impact the underlayment’s performance and lifespan.

1. Proper Installation

Regardless of the type of underlayment, professional installation is crucial. Even the highest-quality underlayment can fail if installed incorrectly. For instance, underlayment must be laid flat and smooth to prevent buckling or tearing that could compromise its integrity. Also, sufficient overlapping of the underlayment sheets ensures a water-tight barrier.

2. Local Building Codes

Ensure your chosen underlayment meets local building code requirements. These rules vary by region and might have specifications for wind resistance, fire resistance, and other safety factors. Adhering to these guidelines is not only a legal necessity but also essential for the safety and durability of your roof.

3. Compatibility with Roofing Material

Different roofing materials may require specific underlayment types. For example, metal roofs often pair best with synthetic underlayment due to its heat-resistant properties, while asphalt shingles may perform well with any of the three types, depending on the local climate and roof slope.

Maintenance and Lifespan of Roofing Underlayment

The best underlayment for roofing is designed to withstand years of exposure to various weather conditions, but no underlayment lasts forever. Regular roof inspections can help identify and address issues such as underlayment deterioration or damage before they escalate.

The lifespan of your roofing underlayment largely depends on the material type, the climate, and the roof’s overall maintenance. Traditional asphalt-saturated felt tends to have a shorter lifespan, generally around 20 years. On the other hand, synthetic and rubberized asphalt underlayments can last up to 40 years or more, provided they’re well-maintained and subjected to average weather conditions.

Additional Considerations

Choosing the best roofing underlayment for your home is a decision that can significantly impact your roof’s longevity and performance. Whether you opt for synthetic roof underlayment, rubberized roof underlayment, or traditional felt underlayment, it is essential to consider your specific circumstances, from the type of roofing – be it asphalt shingle roof or metal roofing – to the local climate and your budget.

Remember, the best roof underlayment is the one that fulfills all these criteria while providing a solid, protective barrier for your roof deck. Synthetic and rubberized underlayment often provide a more durable and weather-resistant choice, proving to be a robust companion to your roofing deck. However, asphalt roofing or felt underlayment can be a suitable alternative for those seeking a more cost-effective option.

Ensuring your roof underlayment is installed professionally is vital to optimize its functionality. Regardless of the underlayment you choose, the installation process can dictate how effectively your roof withstands environmental stressors. So, consult with experienced professionals when you’re ready to install roof underlayment, because a well-chosen and correctly installed underlayment can contribute to a sturdy, long-lasting roof over your head.


synthetic roofing underlayment stands out as one of the best roofing underlayment materials available today, offering advantages over traditional roofing materials like asphalt saturated felt underlayment. As homeowners and contractors become more discerning, the shift towards synthetic underlayments is palpable. It’s crucial to get your roof underlayment installed correctly, and while many might be tempted to stick with what they know, like felt roof underlayment, the benefits of synthetic roof underlayments cannot be ignored. With enhanced durability, resistance to water, and overall superior performance, those looking to install synthetic roof underlayment can expect a longer-lasting barrier between their roof decking and roof shingles.

For homeowners and contractors alike, choosing the right underlayment material is paramount to a roof’s longevity and performance. Brands like Owens Corning continue to innovate, leading the charge in producing top-tier synthetic roofing underlayment options. It’s essential to weigh the pros and cons of both traditional and synthetic options, but as technology progresses, it becomes clear that synthetic roof underlayments are steadily becoming the preferred choice for those who prioritize lasting quality.

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