Platinum Roofing & Construction

Synthetic vs Felt Roofing Underlayment: Which is the Better Option?

When it comes to roofing, the first things that come to our mind are shingles and metal roofing. However, what many roofers normally don’t talk about are the underlayments, which are commonly found as a layer of protection directly above the roof deck & under the roof covering.

This underlayment plays a critical role in protecting your house from things like draftiness and moisture build-up and damage. If your roof doesn’t have a proper roofing underlayment installed, it can easily become vulnerable to water intrusion, leading to black mold development & other issues in the future.

What is Roofing Underlayment & Why Is It Important for Your Roof?

Roofing underlayments are commonly found between the roof sheathing and shingles. They are installed on the roof deck which adds a secondary layer of protection from the elements including rain, snow and wind. These are made of rubberized asphalt, non-asphalt and synthetic materials.

When it comes to roofing underlayment, we often ponder which underlayment will be best suited for our home. Basically, there are two types of roofing underlayments found in most houses and they are namely;

  • Felt
  • Synthetic


So which solution is best suitable for your house? In order to find out, we are going to measure the pros and cons of both in this article. In this way, it will be easier for you to decide which roofing material you should be using in your roof design & which one fits the budget.

Felt Roofing Underlayment

Being one of the oldest roofing underlayments, Felt is made up of saturated paper or fibreglass material mixed with asphalt. Felt roofing is commonly available in two different types: No. 15 and No.30. Comparatively speaking, the No. 15 Felt is relatively stronger & more robust and is significantly less prone to ripping or tearing. It’s one of the reasons why these underlayments often last for longer compared to No. 30.


The biggest advantage of using felt roofing underlayment is that it relatively cost less compared to the synthetic underlayment. So if you’re a budget-conscious homeowner you will like this option. Additionally, it also works great for withstanding both water and mildew issues.


Since it’s a relatively cheaper option, there are several disadvantages to using felt underlayments in your homes. If you leave the underlayment exposed for a prolonged time, the material can easily tend to dry out or leach oils, especially during the summer season.

  • If it’s a windy day and the underlayment is exposed, it can easily experience a tear.
  • When exposed to moisture, the mat can easily absorb water and you may find wrinkles in the felt.
  • If the Felt underlayment which you’ve installed weighs heavy, it can be difficult to lift for roofing contractors.
  • The surface can often become slippery which makes the underlayment hard to install.

The Synthetic Underlayments

Today, many roofing contractors often suggest homeowners get an enhanced water-resistant synthetic underlayment to be installed. Water resistance underlayments are a great option for most roofing because they can easily protect homes from water penetration, even during a heavy downpour. The synthetic underlayments are normally made of standard materials and offer better protection against harsh weather conditions.

However, there are plenty of synthetic underlayment materials which are available offering different levels of performance. Depending on your requirement & research, you can also select composite underlayments for your house roofing.


All synthetic underlayments offer four major advantages over felt roofing underlayments

  • Tough
  • Fast to install
  • Safe
  • Repels moisture


Compared to Felt underlayments, the synthetic underlayments are highly durable and can stand a great deal of foot traffic. At Platinum Roofing & Construction, we believe the right option is the one that offers maximum durability and does not take much impact on weatherization.

Although, our teams can install both kinds of underlayments we normally advise you to go for synthetic roofing underlayments rather than felt roofing underlayments.


Since there are different brands available, it can often become difficult to choose the right one. They are all very competitively priced, each offering its benefits and drawbacks. The upfront investment for the entire roof can be a big one, so it’s best you choose the one that’s perfect for your home requirements. After all, you don’t want to risk your peace of mind at any cost.

It’s why Platinum Roofing & Construction always stands by the customer and helps them in making the right choice. Our team of professionals will help you inspect your roof, assess its condition, evaluate your budget and you’re able to choose the best underlayment.

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