Your roof is one of the most important elements of your home. It keeps your possessions safe from the weather and shelters your loved ones in comfort. Underlayment is a vital part of your roof. You wouldn’t know it from looking at a typical roof. You shouldn’t ever see your underlayment, but it’s certainly there. Keeping everything waterproof. Adding to your home’s energy efficiency. Building layers of durability.

Pick the right underlayment, and you’ll have a roof that can stand against whatever nature throws at it for decades. So it’s a decision that’s worth getting right. The question? What is the best underlayment for roofing?

What Is Underlayment?

Before we begin to look at the specifics of the best underlayment, it’s important to understand what underlayment actually is and how it affects your roof. The underlayment forms one of the primary layers that make up your roof. It lies beneath the exterior layer (the tiles, shingles, or sheeting) and acts as a barrier.

The barrier is there to serve as protection should anything permeate the exterior layer. That includes the likes of rain, snow, hail, or the wind. It certainly helps you avoid the need for emergency roof repair. It also acts as a seal to maintain a comfortable temperature in your home. Forming a layer of insulation.

It also acts as a protective layer for the wooden structure that forms the interior section of your roof. Without protection, these beams could get damaged or rot, causing serious structural damage to your roof.

The Types Of Underlayment

There isn’t just one type of underlayment that would be used for every type of roof. There are three main versions; felt underlayment, synthetic underlayment, and rubberized asphalt underlayment.

Felt Underlayment

Felt underlayment is made from a combination of asphalt and organic materials. It’s what you’ll find in most homes and has been the traditional underlayment of choice for decades. You’ll likely find it in either 15 lb or 30 lb sizes when purchasing materials. It’s a great option thanks to the breathability that allows a great deal of moisture to escape. The main issue is that breathability means it isn’t quite as water-resistant compared to other options.

Synthetic Underlayment

Synthetic underlayment is, as the name suggests, made from synthetic materials. These include polypropylene or polyester, and it forms the more modern solution to felt underlayment. The materials are much lighter than felt, are easier to install, and are more durable. Due to the lack of any organic material, synthetic underlayment is resistant to mold. All of this, however, comes with a price tag considerably higher than its felt counterpart.

Rubberized Asphalt Underlayment

This is the gold standard of underlayment. It’s a combination of durable, strong asphalt and flexible, resistant rubber. It’s often easy to install, with an adhesive side that needs to be pressed in place to form an airtight seal. For properties that regularly face heavy rain or extreme weather, there really is no alternative. This does make it the most expensive option.

Factors To Consider When Choosing Underlayment

It’s not just budget that should be a consideration when picking your underlayment. There are a number of other factors to consider as well:


The underlayment that you can use will depend on the roofing material that you’ve chosen. You might have gone with asphalt shingles, a metal roof, or tiles. Different underlayments adhere better to different roofing materials. So bear that in mind and ensure that the two will work together rather than against one another.


Some regions are going to need considerably better water resistance than others. If you’re dealing with a region where the rain is relentless, make sure you get the most water-resistant underlayment that you can afford. On the other hand, some underlayment offers a higher grade of UV protection, which is ideal for sunny regions.

Roof Structure

The way that your roof slopes will be a factor in the underlayment that you can use. If you’re dealing with a steep incline, you’ll have less sitting water, which means you can deal with a lesser water-resistant underlayment. Flat roofs, however, often have water sitting for an extended period of time and require considerably more water resistance.


More expensive, higher-quality underlayment will come with a warranty to match. That’s an important factor when considering your roofing materials. The best warranties won’t only cover a long duration but also help you with common roof issues.

Building Codes

Some areas will dictate the underlayment that you have to use. Others will give you a freer rein. Check with your local authorities and see what they say about underlayment. This might tie your hands and offer no choice at all!

Investing In High-Quality Underlayment

The best advice is for you to get the best quality underlayment that you can afford. It’s a decision that you won’t regret. Yes, it’ll feel no different in the day-to-day periods of your life, but you’ll appreciate it during the storms you might have the weather. Here are some added benefits of high-quality underlayment:

  • Increases Lifetime Of Roof: A great underlayment protects the underlying roofing system, meaning it will last for considerably longer.
  • Improved Energy Efficiency: A thicker, more robust underlayment makes for a better layer of insulation. Better insulation means lower energy usage.
  • Extreme Weather Protection: If you live in an area that experiences extreme weather, you’ll be pleased that you have the added protection of high-quality underlayment.

Key Takeaways

The main takeaway from this article should be that you get the best underlayment that you can afford to install. It’s an important layer of protection for your roof and, therefore, your home. Make sure that you carefully select the underlayment that will work best for your home and get it installed by a professional.

  • There are various styles of underlayment that you can select based on budget and water resistance.
  • Remember that installing a good underlayment will improve your home’s energy efficiency.
  • You need underlayment to maximize water protection.

If you’re looking for a recognized, professional contractor to install underlayment, then look no further than Trenton Roofing.

Alex Valentino

Alex Valentino – Vice President

Leading the way for the company’s second generation of family and employee ownership, Alex’s mission is to create lasting relationships built on trust and respect by providing uncompromising workmanship and unparalleled customer service. With a focus on safety and consumer education, Trenton Roofing strives to set the bar for the advancement of the roofing industry and the betterment of our local communities. When he is not working, Alex can be found traveling with his fiancée, watching football or playing a relaxing round of golf with his friends.