Can You Use Synthetic Roof Underlayment as House Wrap?

When it comes to protecting your home from the elements, you might be looking for an alternative to traditional house wrap.

In this case, one option to consider is synthetic roof underlayment.

Synthetic roof underlayment boasts an impressive ability to act as a barrier between your home's exterior and its interior living space.

However, is it a suitable choice to replace traditional house wrap?

The short answer is NO.

While synthetic roof underlayment may seem like a viable option for house wrap, it's not recommended.

It is not designed to allow water vapor to escape, which can lead to moisture buildup inside the walls. 

In this article, we'll explain why using synthetic roof underlayment as an alternative is not the best idea and guide you toward better choices.

What is a Synthetic Roof Underlayment?

Caucasian Roofing Worker Installing EPDM Membrane Material Using Hot Air Blower and a Roller

Synthetic roof underlayment, made from polypropylene and polymer, adds an extra protective layer to your roof.

It's typically installed underneath the shingles or other roofing materials, serving as a barrier against water, wind, and other weather elements.

Synthetic underlayment is popular among homeowners due to its superior water resistance and better durability than felt underlayment.

What is a House Wrap?

New house construction on a lot in the Huffman Historic District.

A house wrap is a crucial element of your home's construction, acting as a barrier that keeps moisture out while allowing your home to breathe.

During rain or snow, a well-installed house wrap acts as a second line of defense, safeguarding walls from moisture and significant water damage.

Think of it as a protective jacket for your house, helping to keep it dry and comfortable throughout the year.

Another essential function of house wrap is allowing excess moisture from inside your home to escape.

You might be surprised to learn that everyday activities like cooking, showering, and doing laundry release moisture into the air.

If not properly addressed, it can get trapped in your walls, potentially leading to mold and mildew growth.

A breathable house wrap allows this moisture to leave your walls, helping maintain a healthy living environment.

Continue reading: Can House Wrap Get Rained On? Debunking Weather-Related Myths

So, Can You Use Synthetic Roof Underlayment as House Wrap?

Caucasian Roofing Worker Preparing a Roll of EPDM Roof Membrane Material. Construction Industry Theme.

No, despite the tempting idea of using synthetic roof underlayment as house wrap, it is not a suitable or recommended practice.

Synthetic roof underlayment and house wrap may look similar, but they serve different purposes with unique properties for specific applications.

First, it's essential to understand the main roles of synthetic roof underlayment and house wrap.

Synthetic roof underlayment acts as a protective layer on roofs, blocking moisture and supporting roofing materials.

On the other hand, house wrap is specifically designed to offer more extensive protection to a home's exterior walls.

While some synthetic underlayments are breathable, not all can release trapped moisture in wall assemblies.

In short, using underlayment as a house wrap can lead to unforeseen damage in your home.

Reasons Why You Can’t Use Synthetic Roof Underlayment as House Wrap

Moisture Concerns

One of the main reasons you can't use synthetic roof underlayment as house wrap is moisture concerns.

Synthetic roof underlayments often lack breathability, which can result in trapped moisture, leading to rot, mold, and mildew growth.

The compromised breathability can ultimately affect the structural integrity of your home.

Functions and Requirements are Different

The function and requirements for synthetic roof underlayment and house wraps are different.

While both of these materials can function as weather-resistant barriers, you should not use synthetic roof felt as a house wrap for siding.

Each material's specific properties are tailored to its purpose, so using them interchangeably leads to inadequate protection for your home.

Implications from Building Codes and Regulations

Another reason is that many local building codes and regulations specify the type of materials that can be used as house wrap.

These codes and regulations ensure that buildings are constructed safely with materials tested and proven to provide the required protection.

Using an unapproved material like synthetic roof underlayment might lead to compliance issues and potentially risk your home's safety.

Related article: What Deck Height Requires A Railing? [Code Requirements]

Warranty Concerns

Lastly, using synthetic roof underlayment as house wrap may void the warranties of both the underlayment and the siding products.

Manufacturers often provide warranties based on the assumption that their products will be used as intended.

In short, using synthetic roof underlayment as house wrap can potentially void future warranty claims.

What are Better Alternatives to Synthetic Roof Underlayment as House Wrap?

Closeup of Rolls of new black roofing felt or bitumen. Selective focus and blurred background

Let's look at some better alternatives than synthetic roof underlayment as house wrap.

Synthetic House Wrap

Using a synthetic house wrap specifically designed for this purpose is a better alternative than trying to adapt roofing materials.

Synthetic house wraps offer protection against wind-driven rain, hail, and moisture infiltration, preventing mold growth and structural damage.

Felt Paper or Building Paper

Another alternative you can consider is using felt paper or building paper.

These materials have traditionally been used as house wraps and hold up well in many situations.

Felt paper (asphalt-saturated paper) is an effective house wrap with customizable options in weights and thicknesses to suit your specific needs.

On the other hand, building paper is made from untreated kraft paper, designed to restrict moisture and shed water.

It offers some protection but is less effective in severe weather or high humidity compared to synthetic wraps.

Pros and Cons of Synthetic Roof Underlayment

Waterproofing and insulation at construction site, roof sealing process of synthetic membrane with Hot Air Hand Tool.

Below, we've shared the pros and cons of synthetic roof underlayment.

The Pros


Made from polyethylene and polypropylene, synthetic roof underlayment provides excellent resistance to water and moisture.

With this, you can protect your home against leaks and water damage during its lifespan.

Safety and Traction

Synthetic underlayment offers better traction for roofers during installation, making it safer to work with in various weather conditions.

The Cons

Higher Cost

Synthetic roof underlayment is generally more expensive than traditional felt materials.

However, the benefits of durability and safety often outweigh the initial investment for many homeowners.

Environmental Concerns

The synthetic composition of these materials means they take longer to degrade, potentially contributing to landfill issues over time.

If eco-friendliness is a priority, this may be a factor to consider.

Pros and Cons of House Wrap

House wrap on a new-build house

Here are some of the key pros and cons of using house wrap.

The Pros

Weather-Resistant Barrier

House wraps effectively block rain, snow, and wind from entering your home.

They extend the lifespan of structural components and insulation, ultimately saving you money in the long run.

You might also like: Does House Wrap Stop Wind?


House wraps have a higher perm rating, allowing water vapor to pass through and preventing moisture buildup.

The feature helps prevent issues like rot, mold, and mildew from affecting your home.

The Cons

Vulnerable to Tears and Punctures

House wraps can be susceptible to damage, potentially compromising their effectiveness if not installed correctly.

Climate and Construction Limitations

In extremely cold or humid environments, house wraps might not adequately vent moisture.

Unique construction features, like high exterior foam insulation, may require alternative weather-resistant barrier options.

Be sure to read: Typar Vs. Tyvek Which House Wrap Is Best?

Wrapping it All Together

In conclusion, while synthetic roof underlayment offers excellent protection for your roof, it is not suitable to replace traditional house wrap.

Synthetic underlayment lacks the breathability required for proper moisture ventilation, leading to potential issues like rot, mold, and mildew.

Adhere to codes and regulations; unapproved materials risk jeopardizing your home's safety and warranty coverage.

We hope this article has provided valuable insights into the differences between synthetic roof underlayment and house wrap.

If you have any thoughts or questions, we'd love to hear from you.

Let us know what you think and how we can further assist you in making informed decisions for your home's protection.

A well-protected home ensures a comfortable and secure living space for years to come.

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