Home Home Improvement Synthetic Roofing Underlayment: An in-depth Guide With Facts You Should Know

Synthetic Roofing Underlayment: An in-depth Guide With Facts You Should Know

Synthetic Roofing Underlayment

Given all the advantages, it is not surprising that synthetic underlayment is dominating the roofing sector. In between the shingles is the roof deck, which is typically constructed of plywood or OSB. It provides an extra line of protection from the elements, such as wind, rain, and snow. It is constructed right on the roof deck.

The majority of shingle manufacturers mandate underlayments, and everyone recommends them. Synthetic underlayment is a high-tech, high-performance layer of material installed before the shingles on areas of the roof decking that are not covered by ice and a water shield. With higher performance and additional benefits, synthetic underlayment is the best option. They exist in many forms, and each has advantages and disadvantages. It is suggested to seek guidance from a professional roofer before installing synthetic roofing.

This article provides complete information and a guideline to the readers about the types of rubber roofing for different sheds, their pros and cons, and their conclusion.

Why do you need synthetic roofing underlayment?

There are multiple reasons someone uses synthetic roofing for his house roof. Following are some reasons for applying synthetic roofing to your home.

  • Let’s say your goal is to keep your roof safe from decay, mold, leaks, and moisture damage. In that case, roofing underlayment offers an extra layer of defense that shingles alone can’t. Strong gusts occasionally force singles off course, leaving them open to water contamination. You may fix and rely on your underlayment to stop snow, ice, and rain from damaging your home’s roof deck. The underlayment will provide the necessary defense until the shingles are repaired or replaced.
  • The water-resistant underlayment will form a tight seal around the frame, ensuring water flows off the roof and defending it from leaks caused by seepage when the snow melts onto it and turns to water.
  • Using roofing underlayment that is compatible with the shingles above it and has been certified by industry-standard compliances will help your roof obtain a Class A fire rating.
  • The underlayment offers a homogeneous, flat surface on which you can attach your roofing shingles. When the pattern or uneven areas of the roof deck show through your shingles, it creates the “picture framing” impression. Underlayment, whether synthetic or felt, can assist prevent this from happening.

Types of roofing underlayment

According to the way they are made and the chemicals they contain, there are two primary kinds of roof underlayment. Their ingredients may be similar, but you can fine-tune the manufacturing process and thickness to produce different properties. The types are listed below,

  • Synthetic roofing underlayment
  • Felt roofing underlayment

Synthetic roofing underlayment

Synthetic underlayment is frequently used by roofers to improve weather resistance and water resistance. These items are frequently made of durable polymers, which provide strength and longevity. When laid properly, this underlayment provides superior weather protection since it is often moisture-resistant.

Since the materials used in synthetic roofing underlayment are not specified, different producers may produce their products differently, resulting in products with varying degrees of performance. Do your homework and consult a reputable contractor before choosing the roofing materials that will best protect your home.

Felt roofing underlayment

One of the original kinds of roofing underlayment is felt. It is made by soaking fiberglass mat or paper in asphalt.

The No. 15 felt and the No. 30 felt are the two most popular types of felt roofing underlayment. No. 30 felt is usually thicker, tougher, and possibly less prone to shredding or peeling off during installation or weather events than No. 15 felt.

If felt underlayment is installed, the advantage of the manufacturer’s warranty can’t be taken properly because it might call for synthetic underlayment.

Cost of synthetic roofing underlayments

Because replacing a roof is an expensive investment, cost is always the first item owners consider when they learn it’s time for a new roof. Weight and performance determine how much a synthetic material costs. Greater walkability, durability, and exposure times are among the high-performance characteristics of heavier items. Felt underlayment costs about $5.00 per square (100 square feet), but synthetic underlayments costs between $7.00 and $10.00 per square. Costs for thicker synthetics typically increase by 30% to 40%.

Pros and Cons of synthetic roofing underlayments


There are four key benefits to replacing felt with synthetic underlayment for roofs. Synthetic roofing underlayment is less expensive than felt and has further advantages such as:

  • It is more rigid.
  • It installs on roofs more quickly than felt since there is more material per roll. Three rolls of a synthetic underlayment, for instance, could be needed for a standard 2700 square-foot home.
  • For worker safety, synthetic underlayment is also useful. Indicators of where fasteners should be put and overlap guides are frequently included in well-marked overlaps.
  • Synthetic roofing underlayments are designed to repel water, in contrast to felt products, which tend to absorb it. It is essential for homes worried about moisture intrusion.
  •  It repels water much better than other underlayments.
  • It is usually resistant to tearing and excellent for prolonged UV and moisture exposure. Additionally, synthetic underlayment is resistant to foot traffic.


  • The biggest disadvantage of synthetic roofing underlayment is its high cost and weight, which pushes up labor costs. The more the weight of the roofing material, the higher the labor cost of it.

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How to choose the proper underlayment for your roof?

There are numerous things to consider when choosing the sort of underlayment to utilize, whether you’re starting a new house construction project or a reroofing project. If you want to safeguard your roof and house from the threats of water and moisture intrusion, synthetic roofing underlayment has numerous advantages over felt.


There are numerous things to consider when deciding what underlayment to use, regardless of whether you are starting a roof repair project or building a new home. Let’s say your goal is to prevent potential water damage to your roof and house. In that case, synthetic roofing underlayment has numerous benefits. It is required to consult an experienced roofer before installing the synthetic roofing at home. This article is comprehensive guidance to spread knowledge about the facts everyone needs to know about synthetic roofing underlayment.

Frequently Asked Questions (FAQs)

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