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What Roofing Underlayment Should You Use?

Roofing underlayment is a crucial part of every roof so it’s important to get the right type. Here’s everything you need to know in order to find the best one for you.

Roofing Underlayment - All Climate Roofing

If you’re planning to have a new roof put on your home, you’ve probably put a lot of thought into what kind of roof to use. However, what you may not have thought of is the type of roofing underlayment you need. This is so important to your roof, so you need to ensure you’re picking the right type for you. Here’s everything you need to know before you have your new roof installed.

What is Roofing Underlayment?

Roofing underlayment is the barrier that’s laid on your roof before the top layer, such as metal sheets or shingles are placed on top. This is a crucial part of your roof, as it offers the best barrier against water. Your roof’s going to encounter a lot of water over its lifespan, such as rain, snow, and hail.

Having that underlayment ensures that you can avoid most damage that comes from water in your roof. It also helps avoid mold, which causes damage and leads to health issues. For example, rainwater leaking through a roof leads to wood rot in your timbers, which will require you to replace your roof entirely when left for long enough.

This is why it’s so crucial to find the right underlayment and have it installed with your roof.

Types of Roofing Underlayment

There are several different types of underlayment out there, so you’ll need to find the one that suits your needs best. Here are the most common types of underlayment that are available to you.

Asphalt saturated felt: This used to be the most common type of underlayment out there. It’s also known as tar or felt paper and uses asphalt, polyester, bitumen, and cellulose materials. The basemat of this underlayment uses asphalt to make it water-resistant.

Rubberized asphalt: This is one of the most expensive options, but it’s one of the most effective. It uses a high amount of rubber polymer and asphalt to create a 100% waterproof seal. As it’s so effective, it is more expensive than other options, so you’ll need to decide whether this is in your budget.

Synthetic underlayment: These days, this is the most common underlayment you’ll see in modern roofs. It uses an asphalt-saturated basemat like asphalt-saturated felt but also uses a mix of fiberglass too. This helps improve its water resistance, as well as making it stronger. This allows it to be less prone to tears or damage. You’ll also find some types of synthetic underlayment that have anti-slip properties.

What to Look For in Roofing Underlayment

As you can see, there’s plenty of choices when it comes to underlayment for your new roof. You’ll need to choose which kind of underlayment you’ll use, so you need to think about what you need from yours.

Firstly, you need to consider water resistance. This is the most important thing you need from your underlayment, so you need something that offers a good amount of resistance. If you live somewhere that gets a lot of snow or rain, you may want to invest in something with more resistance, such as rubberized asphalt.

Also, make sure you’re considering the tear and damage resistance that your underlayment has. Good underlayment will resist most damage, so you can be sure that water won’t be making its way through.

What you may not know about underlayment is that the right one can actually help lower energy costs. Some out there have UV protection, which will help reflect heat rather than let it get into your home. Because of this, you’ll be able to reduce cooling costs and protect the planet simultaneously. Look into this if you live in a warmer climate.

Finally, consider installation costs. Some types of underlayment are going to cost more to install. For example, rubber synthetics take longer to install, so you’ll pay more for the process. Synthetic underlayment is a quicker option so that it will keep the costs down.

There’s a lot to think about when you’re looking to pick the right underlayment. If you consider what you need when it comes to weather and pricing, you should be able to pick the right one for you.

How Roofing Underlayment is Installed

Once you’ve picked the right underlayment, you’ll need to have it installed. Like most roofing jobs, it’s always best done by a professional. Finding a good roofing company is crucial, as they will ensure that the underlayment is put down properly, giving you the best protection. You don’t want to take any risks with your roof, after all.

Your underlayment will be attached to the decking of your roof, becoming the last line of protection against the elements and working with your flashing and shingles. To start laying it, roofers will attach drip edge flashing to the roof edge, ensuring it’s straight. Many roofers like to do this in straight lines, as it gives them a straight line to use when attaching shingles. Using that straight line, they can start laying out the underlayment.

The underlayment will then be attached to the roof decking, with the roofers peeling off the paper backing to adhere it to the deck. As they do this, they will be smoothing it out to ensure no bubbles or gaps in the underlayment coverage.

To attach it to the decking, roofers will use one of many different attachments. Staples are popular as they’re simple to use and easy to drive into the roof. 1-inch roofing nails or nails with plastic washers can also be used. Once it’s all attached, the roof shingles can then be attached.


When planning your new roof, you’ll need to consider the underlayment. It’s an important part of your roof’s defense, so you’ll need to ensure that you get it right. Use this guide to find the right roofing underlayment for you, and get a reputable roofing company to handle the installation for you.