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20 Mil Crawl Space Moisture Barrier
  • 20 Mil Crawl Space Moisture Barrier
  • Crawl Space Vapor Barrier
  • 20 Mil Crawl Space Encapsulation
  • 20 Mil Crawl Space Liner
  • 20 Mil Crawl Space Plastic
  • Crawl Space Insulation
  • Foundation Pins™
  • Foundation Pins™
  • Crawl Space Foundation Pins™ - FP-
  • Foundation Seal Tape™
  • Foundation Seal Tape™ - FST-100
  • Waterproof Pro Seam Tape™  - WST-PRO

The SilverBack™ is an actual thickness crawl space vapor barrier that is roughly 30% thicker than other "20 mil" products. This is the premium quality 20 Mil SilverBack™ crawl space vapor barrier for crawl space encapsulation.

This price includes SHIPPING! (some restrictions apply)

This product is subject to a UPS large package handling fee of $9.28 for the first roll of each vapor barrier kind/size.

For more information visit SilverBack™ Product Page

Price: $337.50
In stock
    Availability: In Stock
    Ships Next Day or Sooner™
    • 13

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    Item #: 20MSB-50
    Availability: In Stock
    Ships Next Day or Sooner™
    Item # Description/Size Availability Qty Break Price Quantity
    Plastic fasteners to hold the vapor barrier permanently to the foundation wall
    In Stock 1 $19.99 $18.99
    Super tacky moisture gasket for sealing the vapor barrier to the foundation wall. Does not stick to damp foundations and requires FP-100 to work properly.
    In Stock 32+
    Made with our proprietary adhesive, this seam tape is waterproof and matches our barriers exactly. The Waterproof Pro Seam Tape™ is the tougher, stronger, and more durable choice for your crawl space encapsulation.
    In Stock 12 - 23
    Premium polyurethane caulk for sealing the vapor barrier to the foundation wall in wet locations
    In Stock 1 $6.20 $5.80
    Crawl space moisture meter, reads RH% and air temp
    Sold Out 1 $18.99

    20 Mil Reinforced Vapor Barrier for Crawl Space Encapsulation

    The 20 Mil SilverBack™ is made from 100% virgin polyethylene resin and reinforced with a 1000 denier polyester cord. This crawl space vapor barrier is idea for use on the crawl space floor because it is an actual 20 mil. We say it is an actual 20 mil because it is measured at the plastic and not across the raised reinforcement threads like other brands are. This makes the SilverBack™ 20 Mil 30% thicker than the competitors 20 mil.

    Comparing product weights the 20 Mil SilverBack™ comes in at 110 pounds per 1000 square feet of product or 110 MSF while the closest competitor's 20 Mil is only 83 MSF and another 74 MSF.

    The SilverBack™ brand is Made in America and does not contain unnecessary additives. There is no odor or off-gassing with this crawl space floor liner.


    The SilverBack™ is easly identified by it's bright white face and silver colored back.

    The 20 Mil SilverBack™ is available in 3 roll sizes:

    • 6'9"x100' (675 sq ft) No welds or seams
    • 13'4"x50' (675 sq ft) One weld/seam
    • 13'4"x90' (1200 sq ft) One weld/seam


    20 Mil SilverBack™ is thick enough and strong enough to allow for medium to heavy storage, heavily traveled areas and to cover stone/concrete floors. We still recommend the use of the Felt550™ if the floor has objects that are sharp and can not be removed.
    Use the 20 Mil SilverBack™ on the floor and the 12 Mil SilverBack™ on the walls to keep the costs inside the budget.
    20 Mil= .020 inches

    The 20 Mil SilverBack roll size is approximately 86" for all three roll sizes. We take the wider rolls and fold them in half before rolling them on a thick cardboard core. This 20 Mil product will measure at least 20 mil (.020 inches) at the center of the diamond pattern and approximately 26 mil at the string reinforcement.

    Expect that these rolls are heavy and may need two people to carry them, especially the 90' roll size (145 pounds). Due to its large size, UPS charges a large package handling fee of $9.28 each to deliver to your door.

    Overall Customer Rating of 78 Reviews:

    Initial findings

    This product appears to be everything it says it is. Time will tell. Would recommend this material to anyone for this application.

    Great Experience

    The staff @ was very helpful in helping select the right materials and quantities to do the job right the first time. I highly recommend them.

    S.E. Michigan

    Very durable surface for Radon control.

    • Durable
    • Clean look
    • Radon control
    • Heavy
    • Stiff
    Encapsulated my crawl space with the 20 mil product and I am very pleased with the finished result. The 20 mil thickness is stiffer and a bit harder to work with than the thinner barrier but it has allowed me to use the space for storage as well as a Radon mitigation using a radon fan. I installed over Felt 550 to provide extra protection for the vapor barrier and ensure the ground gasses would be able to move to the pipe under the vapor barrier. The vapor barrier pulled against the crawl space floor when the fan was turned on. Radon levels reduced to <1.

    Gunner insulation

    Product is great to work with and is much better then the old 6mill
    Makes for a much better job

    Atlanta, Ga

    20 Mil Silverback

    I used this 20 mil Silverback on the floor of our crawl space due to the excessive rocks. It was the perfect choice as it is tough and won't wear through. The folks at did an excellent job of guiding me through the installation process. Very easy.