If you’re installing a new metal roof, you have to check the local building code to ensure what type of roof underlayment your project can use. Once you’ve determined synthetic underlayment is suitable for your project, you still have different types and brands of synthetic underlayment to choose from.
At Western States Metal Roofing, we have been in the roofing industry for over 20 years manufacturing metal panels and work closely with roofing contractors everyday to help them find the products that will enable them to have a successful roof installation.
To make your buying decision easier, we go over the main types of synthetic underlayment in this article to help you choose which is best for your installation.
Synthetic underlayment is a layer of laminated polypropylene or polyethylene plastic material that goes over the roof deck. It’s purpose is to provide an extra layer of protection to the roof system. The synthetic material is resistant to moisture and can be left exposed to the element for an extended period of time, making it the right underlayment material to choose when drying in a roof.
Synthetic underlayment has a longer lifespan when compared to felt or asphalt roofing underlayment.
The best synthetic roofing underlayment is an underlayment that matches the lifespan of the roof. For example, if you have a metal roof that’s designed to last 50 plus years, then you should buy an underlayment that has a 50 year warranty.
A superior quality high temperature underlayment, such as the Sharkskin Ultra SA® or Sharkskin Ultra, is considered to be a high quality roof underlayment due to its durability and longevity.
The weight of the underlayment is an excellent indication of the quality of the underlayment. This is especially true with the non adhesive roofing underlayment. In an effort to cut cost, there are many synthetic underlayment on the market that boast about their mil thickness. This can be misleading though as some of these underlayment have a fuzzy top layer that’s a false indicator of the materials thickness.
It’s unusual to have a comparison chart that’s so lopsided, but there’s really only one significant disadvantage for synthetic underlayment. The short term costs are much higher than felt underlayment. However, the long term cost of having an asphalt underlayment that fails prior to the roof system will be catastrophic.
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PROS Of Synthetic Roof Underlayment |
CONS Of Synthetic Roof Underlayment |
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Greater Resistance To Mold And Mildew |
More Expensive Than Felt |
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Can Be Left Exposed For Long Periods Of Time |
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Safer To Walk On |
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Lasts Longer (25-50 years) |
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Lighter And Easier To Install/ Work With For DIY |
Synthetic underlayment is more lightweight than felt which makes it easier to carry and install. Synthetic underlayment also provides better traction for roofers than roofing felt in both wet and dry conditions, making it a safer product to work with during installation.
For a further comparison on the differences between synthetic and felt underlayment, we recommend reading:
Synthetic vs. Felt Roof Underlayment: Which Should I Use?
One of synthetic underlayment’s advantages is its long lifespan. Synthetic roofing underlayment will have a warranty that ranges from 25-50 years, while felt underlayment only lasts 12-20 years. In addition, synthetic underlayment can be left exposed for months. Conversely, felt cannot be left exposed for long periods of time. This becomes important if your project is not able to be completed immediately.
The price of synthetic roof underlayment will vary depending on the lifespan of the product and whether it’s non adhesive or self adhesive.
Though underlayment is a small expense when you look at the overall cost of your installed roof, it is one of the most important components of a long lasting roof.
While there are different types of roof underlayment, most manufacturers follow the model of having a “good, better, best” option that ranges in terms of quality and price.
For this article, we will use the Sharkskin manufacturer product line to discuss the types of synthetic underlayment.
Sharkskin Comp® is a quality high temperature rated non adhesive synthetic roofing underlayment that is a great choice for metal and shingle roofing. Though this is the entry level synthetic underlayment, it is considered throughout the roofing industry to be superior to felt underlayment. Sharkskin Comp® comes with a 30 year warranty under warranty.
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PROS |
CONS |
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Most affordable |
Least UV resistance (6 months) |
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Safer and easier to work with compared to felt underlayment |
Not suitable for all roofing materials |
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Shorter warranty (25 years) |
A roll of Sharkskin Comp® is 48” wide, 10 squares and weighs 40 pounds.
Sharkskin Comp® has UV resistance for up to 6 months.
When purchased through a manufacturer, the price of a synthetic underlayment roll decreases as quantity purchased increases. It will cost between $.15 to $.20 per square foot.
Sharkskin Ultra® is a quality high temperature rated, non-adhesive synthetic underlayment that is suited for metal, shingles, tile, and slate roofing systems. It’s heavier and more durable than Sharkskin Comp®. Sharkskin Ultra® comes with a 50 year warranty. It’s the best non peel and stick underlayment.
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PROS |
CONS |
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Suitable for most roofing materials |
More expensive than Sharkskin Comp® |
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50 year warranty |
Non adhesive |
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12 month UV exposure |
Sharkskin Ultra® is 48” wide and 250 lineal feet. Each roll weighs 50 pounds and is 10 squares.
Sharkskin Ultra® can be left exposed for up to 12 months.
When purchased through a manufacturer, the price of a synthetic underlayment roll decreases as quantity purchased increases. It will cost between $.20 to $.25 per square foot.
Sharkskin Ultra SA® is a “state of the art” high temp rated peel and stick roof underlayment. As the underlayment with the most superior quality in the Sharkskin series, it is the ideal underlayment material for all roofing types including asphalt shingles, metal, tile, and slate roofs.
Ultra SA provides durable secondary moisture protection in high velocity wind zones and is an excellent choice for areas with extreme weather and snow conditions. Sharkskin Ultra SA® comes with a 50 year warranty.
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PROS |
CONS |
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All weather barrier- maximum durability |
Most expensive |
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Suitable for most roofing materials |
Less coverage per roll |
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Requires fewer rolls to comply with “ice barrier” codes |
Sharkskin Ultra SA® is 48” wide and 125 lineal feet. Each roll weighs 65 pounds and contains 5 squares per roll.
8” mini rolls are also available. These are used to cover the valleys and eaves of a roof.
Sharkskin Ultra SA® can be left exposed for up to 12 months.
When purchased through a metal roofing manufacturer, the price of a synthetic underlayment roll decreases as quantity purchased increases. It will cost between $.55 to $.65 per square foot.
Ice and water shield is another name for peel and stick underlayment. It’s an excellent underlayment choice, especially for roofs that have low slopes and in climates that experience heavy rain, winds, and snow. The durability of peel and stick roof underlayment makes it more effective at minimizing the risk of water penetration which would result in damage to the roofing system. In fact, building codes in heavy rain and snow country areas often require the installation of ice and water shield underlayment.
Self adhesive roof underlayment can also be used in conjunction with a non adhesive underlayment. In these instances it’s used along the areas of a roof that pose the greatest risk of ice damage or water intrusion such as the eaves, rakes, ridges, and valleys. The 8” rolls are used in these areas which saves installation time.
Peel and stick underlayment is a flexible material that is preferred by roofing contractors because it’s easy to work with and makes for a simple installation. It also lays flatter on the roof deck than non-adhesive underlayment, making for a smooth foundation for your roofing material.
Synthetic underlayment is available for purchase through most metal roof suppliers including big box stores such as Home Depot or Lowes. However, you are limited to the quantity and quality of what they have in stock.
If you are working with a roofing contractor, most will provide all accessories for the installation, including the underlayment, and roll the cost of the materials into the installation quote.
If you are installing the roof yourself and have a materials list, you can purchase underlayment and all the materials you need for your installation through a metal manufacturer. As mentioned in the cost sections above, the more quantity you buy with a manufacturer, the cheaper the underlayment is per roll.
Synthetic underlayment is a sturdy, dependable type of underlayment that will outlast any felt material. When choosing your underlayment, you want to make sure you consult the local building code so that the type you choose meets area standards. Also make sure that the selected underlayment is permitted by the metal manufacturer so that you do not void the metal panel warranty.
Other considerations to make when choosing underlayment:
At Western States Metal Roofing, we understand how important using quality products is to having a successful roof installation and we take pride in the products we offer.
Choosing the right underlayment for your roof can be confusing. Our team is happy to answer any questions you have. We have roofing underlayment ready to be shipped immediately in addition to all of our other roofing products and accessories. We can also provide you with a free quote for any of our products.