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    Roofing Underlayments EXPLAINED by a roofer: Tar Paper, Synthetic, Ice and Water Shield

    When it comes to the roofing industry, many contractors and homeowners focus solely on the shingles being used

    Yet, there are so many more components to a roofing job that often get overlooked, like roofing underlayments.

    Just recently, Roofing Insights co-host Brent Simmons examined the different types of nails that contractors use when performing roof installations.

    Now, Simmons and Roofing Insights are diving into the oft-forgotten subject of underlayment, the goal being to inform homeowners of one more aspect of the roof installation process.

    Keep reading to learn about the different types of roofing underlayments and which one is best for your home!

    Before examining the specific types of underlayment, it is imperative that as a homeowner you understand what exactly underlayment does for your home.

    According to Simmons, underlayment simply serves to protect your home from water that the shingles situated above it cannot capture.

    “Underlayments are basically what the name implies,”

    says Simmons.

    “It’s an underlayment for the final roofing product.”

    “They go between the shingles and the roof deck. This is a second layer of protection for if something were to happen to the shingles.”

    Real quick: there are five different types of underlayments.

    Keep scrolling to learn more about each type of underlayment.

    1. Asphalt/felt/tar paper

    “There are a ton of different names for them, but this is one of the oldest forms of underlayment that’s still around,”

    Simmons says of asphalt, felt, and tar paper.

    This type of underlayment is made out of wood pulp and other organic materials, which acts as paper that is coated with an asphalt layer on top of it.

    “What the asphalt does is it actually helps the water shed off so the roof doesn’t absorb water, but you are not going to see a lot of roofing companies install these products,”

    explains Simmons.

    The reason for this is because this type of underlayment has been replaced by a more efficient product, which brings us to underlayment number two…

    2. Synthetic felt

    This is a polypropylene synthetic membrane. It serves the same purpose as tar paper and asphalt underlayment.

    Synthetic felt is considerably larger than felt paper, but with added benefits like strength and durability, the benefits of installing synthetic felt underlayment are noticeable.

    “You will find these underlayments on every single roof, or at least you should be finding them there,”

    Simmons says of the synthetic felt.

    3. Ice and water shield

    This kind of underlayment is a unique product that has a plastic layer which protects the backside of the underlayment, which is useful for roofs that have more complex designs.

    “The purpose of this underlayment is to actually go in areas that are more prone to leaking, so in the valleys of roofs, around chimneys, and end walls where the roof meets the wall,”

    says Simmons.

    “That’s where you’re supposed to put this underlayment. What’s so cool about it is that when it heats up it will stick to the decking really well, making it almost impossible to remove. Any nails that get driven through this product will actually seal around it when it gets hot.”

    4. High-temp ice and water shield

    You already know about the standard ice and water shield underlayment, but manufacturers have also designed an upgraded version that is still gaining traction in the roofing industry.

    This product is actually so new to the market, that Simmons says he has not yet seen it installed on a roof.

    “It almost looks like synthetic felt on the surface, but you still have that sticky backing,”

    Simmons says while examining the product, adding that the high-temp ice and water shield was designed for specific climates.

    “You are supposed to use this in areas where it gets extremely hot, like under metal roofs, copper roofs, and standing seam.”

    The high-temp ice and water underlayment is also compatible with synthetic tiles, clay tiles, and concrete tiles.

    5. Base sheet

    The last type of underlayments are base sheets.

    They are part of rolled roofing systems, which are granulated flat roofs that you usually see on very low-pitched roofs.

    In these instances, base sheets are installed before putting on the granulated caps sheet.

    This product also has markings on it so you can determine the spacing on the cap.

    “Base sheets are similar to ice and water shield because you have a sticky backing. It’s quite a bit thicker as well,”

    says Simmons.

    There are many other underlayment products on the market, but Simmons and Roofing Insights have found the five in this list to be the most common.

    If you know of any other types of underlayments currently on the market, let Simmons and Roofing Insights know in the comment section below!

    And before you go, don’t forget to subscribe to all of Roofing Insights’ social media channels so you never miss any of their upcoming content!

    Quentin Super
    Senior Copywriter at Roofing Insights, author of the internationally-selling book The Long Road North, founder of quentinsuper.com

    Recent Articles

    Roofing Online Business School
    Our school will teach you everything you need
    to know about the roofing business
    Roofing Process Conference
    December 9th - 10th, 2021
    Rosen Centre
    9840 International Dr, Orlando, FL 32819

    1 Comment

    1. I understand that some newer synthetic underlayments also provide a radiant barrier function. If that is true can you tell us more on how to reduce the heat in the attic.

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