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Underslab Vapor Barrier
Perminator Vapor Barrier
The premier underslab vapor barrier — low permeability, high puncture resistance, and available in 10 mil and 15 mil thicknesses. Engineered to reduce moisture, water vapor, and radon gas through the slab, while limiting fungus, mildew, and mold.
Free shipping, all orders
10 mil & 15 mil thicknesses
Made in the USA
Perminator is an underslab vapor barrier. It comes in 10 and 15 mil thicknesses and is made to reduce the penetration of moisture, water vapor, and radon gas through the slab of the structure. Perminator also reduces the growth of fungus, mildew, and mold.
The Product
Underslab Vapor Barrier
Perminator underslab vapor barrier is the next generation of polyolefin-based resin chemical technology. It offers one of the best vapor barriers in the industry — an extremely effective, economical option for reducing the penetration of moisture and water vapor from the slab into the structure. In turn, it reduces the growth of fungus, mildew, and mold, and limits radon gas from getting into the structure.
It's available in two thicknesses, 10 mil and 15 mil, both offered in 200-foot (61m) long rolls. The barrier prevents uncontrolled moisture from getting into the slab, allowing the slab to maintain the maximum moisture emission rate and humidity level allowed by the flooring manufacturer's specifications.
The 12-foot-wide 15 mil and 15-foot-wide 10 mil rolls require fewer seams during application, making installation faster and easier. All side and end seams should overlap 6 inches, then be taped with 4-inch-wide P-Tape from W.R. Meadows. The rolls move quickly and smoothly over level, tamped soil or compacted fill.
Strength
Puncture Resistance
This resin technology provides greater puncture resistance while maintaining one of the lowest perm ratings in the industry. It won't crack, tear, snag, puncture, or split easily — strong enough to stand up to normal construction jobsite conditions and traffic.
Available in 10 mil and 15 mil thicknesses in 200-foot rolls.
Reduces moisture and water vapor penetration through the slab into the structure.
Reduces fungus, mold, and mildew.
Reduces radon gas from entering the structure, and is resistant to methane gas.
Strong enough to withstand normal construction conditions and traffic — won't crack, snag, puncture, tear, or split easily.
Installs quickly over tamped grade — no sand, gravel, or fill needed.
Wide rolls require fewer seams; thickness is clearly marked on the membrane for on-site identification.
VOC content is 0 g/L, and the product is made in the USA.
How Perminator Is Installed
Perminator is designed for underslab construction over tamped, leveled, or compacted fill. The 200-foot sheets can be unrolled as-is or cut to size, then installed using the overlapping approach. Follow ASTM E1643 practice for installing vapor retarders in contact with earth or fill under concrete slabs.
1
Prepare the surface
Level, tamp, or roll the earth or granular material beneath the slab base per the architectural drawings, following ASTM E1643 practice and procedure.
2
Roll out and overlap
Unroll the barrier over the pour area and cut to size so it fully covers the area. All side and end seams overlap 6 inches, then are taped with 4-inch-wide P-Tape. Keep the tape's adhesion area free of dust, dirt, and moisture for maximum bond.
3
Tie into the footing and wall
Place the roll onto the footing and against the wall to sandwich the barrier between footing, vertical wall, and the poured floor. Where local codes prohibit placement over the footing, W.R. Meadows approves the alternative method when required by building code.
4
Seal all projections
Cut a slit around pipes, ductwork, wire penetrations, and rebar, then add a collar around each pipe. Cut a piece at least 12 inches wide and 1.5× the pipe circumference, cut "fingers" halfway across, wrap, and tape the collar and fingers to the base layer.
5
Repair any damage before the pour
Cut a patch large enough to cover damage with a 6-inch minimum overlap in all directions, clean the adhesion area, and tape down all edges. Confirm all penetrations, block-outs, and damaged areas are repaired before placing concrete.
Caution
This underslab vapor barrier does not eliminate the need for relief of hydrostatic heads. A complete drain-tile system should be placed on both the exterior and interior of the footing. For best concrete performance and durability, the floor slab design should use the lowest possible slump while ensuring complete hydration. You don't need to overlay the rolls with gravel or sand — the product is strong enough to withstand normal construction traffic, and most flooring companies recommend placing the slab directly onto the barrier to avoid the blotter effect.
Perminator Tape
Perminator P-Tape is the correct 4-inch-wide tape for sealing seams when installing this underslab retarder.
Frequently Asked Questions
Where is this product made?
The Perminator product line is made in the USA.
How do I install it?
See the installation steps above, or watch the installation video below for a walkthrough.
Can I buy one roll instead of 12?
At this time we only sell full pallet sizes of 12 rolls.
Specification Guide
Vapor Retarder or Vapor Barrier?
Underslab vapor retarders (or barriers) are a productive, cost-effective way to control moving moisture in concrete. Correct installation beneath the slab has proven to reduce or eliminate the problems that arise when moisture reaches interior spaces — damage to floor coverings and coatings, and compromised indoor air quality from fungus, mildew, and mold. The two terms are used interchangeably in the industry, so it's the material's function and performance that matter, not the label.
Under the International Building Code, vapor retarders are separated into three general classes based on permeance:
Class I
A vapor retarder of 0.1 perm or less.
Class II
1.0 perm or less and greater than 0.1 perm.
Class III
10 perms or less but greater than 1.0 perm. Anything over 10 perms is a vapor-permeable membrane.
Most people consider a "vapor barrier" to be a Class I vapor retarder. ACI 302.1R notes that many retarder materials are mistakenly called barriers; true barriers are described as having a permeance of 0.00 perms per ASTM E96. ACI 302.2R adds that where extremely moisture-sensitive flooring is involved, materials with 0.01 perms or less may be the better choice. The lower the perm rating, the better the protection — but a low perm rating alone does not make an effective retarder.
Three ASTM standards govern underslab vapor retarders — two material specifications and one for installation:
ASTM E1745
Plastic water vapor retarders used in contact with soil or granular fill under concrete slabs. Classified A, B, or C by tensile strength and puncture resistance — not permeance, which is consistent at 0.1 perms across classes.
ASTM E1993
Bituminous water vapor retarders used in contact with soil or granular fill under slabs, specifying water vapor permeance, tensile strength, puncture resistance, and thickness.
ASTM E1643
Standard practice for selection, design, installation, and inspection of water vapor retarders used in contact with soil or fill under slabs.
Beyond permeance: during construction, materials face foot traffic and conditions that cause punctures and tears. Even small holes can dramatically increase water-vapor emissions through the slab. One Aberdeen Group study found a 1/8-inch nail hole raised the average emission rate enough to equal a retarder with a 0.93 perm rating, and a 5/8-inch stake hole pushed it to a 2.2 perm equivalent — well beyond recommended performance. The takeaway: you need a balance of low vapor permeance and high puncture resistance for a retarder that performs during installation and provides long-term protection. Always confirm the permeance and puncture properties on the manufacturer's datasheet have been independently tested by an accredited lab on samples from the same production roll, per Section 1.1 of ASTM E1745.