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Synthetic Roof Underlayment vs Felt

When it comes to roofs, people initially think about metal roofing or shingles. Some people tend to miss out on the essential layer of protection that lays directly on top of the home’s deck and is placed under the roof covering. It serves a very critical role to protect any home from damage caused by moisture. This important layer of protection is called roof underlayment.

Source: peakroofingconstruction.com

Read along to learn more about this essential aspect of a roof’s system.

Roofing Underlayment 

A roofing underlayment lies just between the shingles and the roof deck or roof sheathing. It is installed on top of the roof deck and offers an added layer of protection from the different elements such as rain, wind, and snow. 

To further understand roofing, it is essential to know about its two major types: synthetic roof underlayment and felt underlayment. They both have their pros and cons. Choosing between them may depend on a homeowner’s needs such as location, roof design, roofing materials used, and budget.

Synthetic Roof Underlayment

Due to protection from the elements and enhanced water resistance, a lot of roofers choose this type of roof underlayment. These are typically made from polymers that offer added longevity and strength. This underlayment is moisture-resistant and when correctly installed, provides better protection compared to felt.

There are no standardized synthetic underlayment materials. Thus, manufacturers may create products differently and may have various performance levels.

Pros of Synthetic Roof Underlayment

  • Quick Installation
  • Tough
  • Repels Water
  • Safe

Synthetic roof underlayment has a more durable construction and a higher tear strength when compared to felt. It offers extreme durability and does not tear. This works best especially in areas usually exposed to UV and moisture. Another great feature of synthetic underlayment is that it is strong against boot traffic. This means that when someone walks on the roof, especially during installation or maintenance times, there would be no need to worry.

Synthetic roofing underlayment is also much lighter than felt underlayment. In most cases, it is even four times lighter

This type of roof underlayment is easier and faster to install because it comes in longer and wider rolls. This is due to the materials included per roll. Having a bigger roll means saving time to get the installation done. A longer roll can cover a bigger area of the roof.

When it comes to safety, synthetic underlayment offers an advantage because it typically comes with slip-resistant surfaces and lessens the risk of falls. It usually has overlap indicators or guides that are well-marked. These contribute to accuracy and consistency upon installation. 

Another advantage of synthetic roof underlayment versus felt is that it is moisture-resistant. It is created to repel water while felt roofing underlayment is made to absorb it. For homeowners who are concerned about moisture damage, it is highly essential to consider this as a basis for choosing the type of roof underlayment. Due to the plastic quality of synthetic roof underlayment, it is more resistant to mold growth.

Cons of Synthetic Underlayment

Majority of synthetic underlayments are competitively priced. When it comes to price, felt underlayment is the more favorable option. However, if homeowners would look into the higher quality materials utilized on synthetic roof underlayments then the price may not be a huge factor. 

Felt Roof Underlayment

Felt roof underlayment has been one of the longest-used types of roof underlayment. It is created via saturating paper or fiberglass mat with an asphalt material. It is usually available in 2 types: No. 30 and No. 15 felt. The No. 30 type is thicker and stronger compared to the No. 15 type. Thus, No. 30 felt is more recommended against tearing during severe weather.

Pros of Felt Roof Underlayment

The number one advantage of choosing felt roof underlayment is the cost. The price range of felt underlayment is more affordable compared to synthetic roof underlayment. Homeowners who have a very strict budget for their homes typically go for felt underlayment. 

Cons of Felt Roof Underlayment

Using felt roof underlayment has several disadvantages. One of these is that traditional felt underlayment cannot be left highly exposed for a very long time. The material may tend to leach oils or dry out in the heat. This could lead to affecting the ability of felt to protect the roof against moisture damage.

Felt roof underlayment is also prone to potential tearing during high winds. When it gets exposed to moisture, its mat can showcase wrinkles when the mat starts to absorb water. This would make the laying of the shingles harder as it would need to be flat. The shingles must be installed as soon as the felt underlayment is installed to achieve optimal protection. 

Another drawback of felt roof underlayment is its weight. Roofing contractors will have a harder time dragging the rolls up the ladder. In addition, the weight contributes to the less material each roll. More seams are required with shorter rolls. The surface of this type of underlayment is slippery and can make it harder to install as well.

Warranties are quite more complicated when felt roofing underlayment is used as manufacturer warranty may require synthetic roof underlayment and this could prevent a homeowner from being warranty-protected. 

Choosing the Right Roof Underlayment

Understanding the importance of roof underlayment is highly essential to have a durable roofing system. Knowing the two major types is important to compare the pros and cons of both. The factors mentioned above can serve as a helpful basis to assist any homeowner who may be embarking on a new home project or a re-roofing task. Understanding the advantages of synthetic underlayment against felt underlayment aside from cost can help homeowners realize why most professionals choose the former.

Choosing the roof underlayment may serve as choosing an investment for a home. Picking the best for long-term use can also save money in the long run. Nevertheless, homeowners may have their preferences. If cost outweighs everything then felt underlayment towers over synthetic. The important thing is that options are available and homeowners can weigh what works best for their needs.

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