Roof Underlayment: What is the Best Type for Your Home?

Man applying roof underlayment during roof replacement.

Choosing which roof underlayment to apply to your roof isn’t an easy decision. You want to make the right choice since your roof is one of the leading areas of protection in your home. It protects your home’s interior from harsh weather conditions. There are many options available when considering the underlayment you want.

Let’s review exactly what roof underlayment is, and then we’ll take a look at some of the different types available today.

What is Roof Underlayment?

Roof underlayment is the first layer of protection against water damage, fire, or high winds. Builders install it under your shingles or other roof material as a layer of defense against all types of weather as well as other unpredictable incidents.

Roof underlayment protects your roof deck in the event your roof needs to be replaced. When roofers remove your shingles, your home is still protected while the shingles get replaced.

Additionally, having a layer of underlayment has shown to raise the fire rating for roofing systems. It also gives workers traction when working on your roof, reducing the likelihood of an accident.

Using underlayment helps increase and maintain the value of your home because the added layer of protection means you are at less of a risk for an accident of any kind. You are also likely to pay less for homeowners insurance because the chances of damage are smaller and present less risk to the insurance company.

Men on Roof - Roofing Underlayment allows them to work without damaging the roof deck.
Image: CC BY 2.0, by Angel, via Flickr

Why Use Roofing Underlayment?

There are a lot of benefits associated with adding this layer of protection.

Repel water

It is possible for rain or snow to get under your shingles. This puts your roof deck at risk of water and moisture damage, mold, rot, and leaks. Using an additional layer of underlayment provides more protection. Instead of leaking into your home, the water drains away from the roof.

Additional protection from water and ice damage

If you reside in a northern environment, you’ll have snow and ice to consider. After a snow or ice storm, the heat from inside your home melts what remains on your roof. This which means the water can seep into small spaces and eventually, into your house. This can cause damage to your ceiling, insulation, or walls. Using the best underlayment for your home can provide an extra layer of protection.

Inclimate weather protection

If you live in an area where harsh weather conditions occur frequently, you’ll be glad you have the added protection of roof underlayment. In the event your shingles are torn loose from your home, the underlayment will protect your wood roof deck from water until you can get the shingles replaced.

Fire rating requirement

The fire rating of a shingle is determined using a small deck test with the roof underlayment in place. Without the underlayment, the shingle alone may not pass the necessary fire requirements. When selecting an underlayment, it is essential to ensure it is compatible with your shingle type. You also want to be sure they meet the appropriate building codes.

Protects while you work

If you have underlayment in place, your roof deck will have the coverage it needs. You want to be sure your roof deck has protection before or while you’re working on installing or replacing your shingles.

Roof Underlayment Ridge
Image: CC BY 2.0, by Brian Robinson, via Flickr


The chances are good that your roof deck does not lie in a perfectly flat or straight line. Using roof underlayment gives your home a uniform look and even surface, which can be used to install your shingles. Adding an extra layer on top of the uneven roof deck can prevent bubbles or wrinkles from forming in the shingles.

Resin stains

Depending on the type of wood used for your roof deck, you may run the risk of having small amounts of resin leach through over time. Putting down this layer will prevent and protect your shingles from staining.

Types of Roof Underlayment

There is a wide variety of roof underlayment. It is essential to have a solid understanding of each, so you can make sure you’re making the right decision for your home. Keep in mind that each type of underlayment also has different thicknesses from which to choose. Typically, thicker sizes provide more protection.


synthetic roof underlayment roll
Image via Amazon

Where felt is typically the roof underlayment of choice, synthetic rolls are quickly replacing it. Synthetic underlayment consists of weaved polymers, which creates a more dense barrier against rain, snow, and high winds.

If you have a slate or metal roof, synthetic underlayment may make more sense. Synthetic roof underlayment is superior to other types of underlayment in its vapor resistance level. Vapors can cause moisture to become trapped below the roofing on metal or slate roofs, and over the long term can cause decay and rot.

Rhino roof underlayment

One specific type of synthetic roof underlayment is RhinoRoof. RhinoRoof underlayment is attached mechanically to your roof deck. It provides the durability and strength needed to last the lifetime of your roof. RhinoRoof comes with a 20-year warranty and will provide the protection your roof needs.


If money is a concern, going with felt roof underlayment will let you stretch your money a little. Felt protects against water and moisture and usually comes in thicker layers than other types of underlayment.

It typically consists of wood cellulose. It has a protective layer that repels water. Using felt underlayment between your decking and shingles allows for a longer lasting roof.

Rubberized asphalt

Most rubberized asphalt roof underlayment is a peel and stick product that adheres to the roof deck. This type is best for metal roof underlayment since they protect in places you may not think to address.

In comparison to other types of roof underlayment, rubberized asphalt is capable of withstanding higher temperatures. Rubberized asphalt roof underlayment is also vapor impermeable. This means it can resist changes in air pressure to provide a barrier to protect your home and roof deck.

Roof Underlayment supports this Shingle Roof
Image: CC BY 2.0, by Inga Munsinger Cotton, via Flickr

Roofing Codes

Many jurisdictions have building codes that dictate requirements for roof construction, including the type of underlayment and shingles. Check your homeowner’s association bylaws or city code for specific details when choosing which type you need. Below are a few of the options.


The most common types of underlayment in residential areas are felt and synthetic. They are lightweight and cost-effective, so they fit more easily into a homeowner’s budget.

However, some residential areas allow for tile and slate roofs, in which case you need an asphalt underlayment. It can be more cumbersome than other types and a bit more challenging to work with, but you need the increased moisture buildup prevention that comes with it. Tile and slate roofs tend to have more leaks than other types of roofs because they allow for moisture buildup.


Metal roofs, such as those found on commercial buildings or barns, require synthetic underlayment. Heat gets trapped under metal roofs, and when it builds up over a long period of time, the synthetic underlayment retains moisture, keeping it from drying out. This provides better slip resistance during installation and has a high fire rating. It’s also stronger than most other types of roof underlayment.

What is the Best Roof Underlayment for Your Home

No matter what type of roof you have, it is highly recommended that you use some kind of roof underlayment. But which type is the best for your home? Well, it all depends on the type of roof you have.

At the end of the day, you need to make the decision that is right for you and your home. Do your research and ask the roof manufacturer or home builder if there is a recommended type of roof underlayment that you should use. Hopefully, some of the information provided in this article gave you a good starting point for what is best for your home.


Featured Image: CC BY 2.0, by Brian Robinson, via Flickr


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