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W.R. MEADOWS Premoulded Membrane (PMPC )



Vaporproofing/Waterproofing Membrane

PREMOULDED MEMBRANE VAPOR SEAL WITH PLASMATIC CORE (PMPC) is a patented seven-ply, weather-coated, permanently bonded, semi-flexible vaporproofing/waterproofing membrane. It is composed of an exclusive PLASMATIC CORE suspended mid-point between two layers of a homogeneous, bituminous material, and then sealed under heat and pressure between liners of asphalt-impregnated felt and a glass-mat liner. An asphalt weather coat is applied to the glass-mat liner and covered with a polyethylene anti-stick sheet.


PMPC provides a positive, easy-to-install, economical, true vaporproofing and waterproofing system for horizontal applications. Properly applied, it stops moisture migration in footings, concrete floors, and structural slabs. PREMOULDED MEMBRANE VAPOR SEAL WITH PLASMATIC CORE is both waterproof and vaporproof.


It offers a perm rating of less than 0.002 perms, the lowest in the industry. The product is the ultimate when a true vapor seal is required. Among its unique features is the built-in protection course, which resists jobsite puncturing and the abrasive action of concrete placement. PMPC conforms to ASTM E1993-08.  The exclusive PLASMATIC CORE adds flexibility, greater tensile strength, and excellent handling characteristics, in addition to providing unequalled vapor barrier properties.  PMPC helps meet and maintain the maximum slab moisture transfer rate of 3 lb./1000 ft.2/24 hours (1.45 kg/100 m²/24 hours), as allowed by the flooring industry’s specifications.


PMPC, when properly applied, is designed to stop moisture migration (liquid or vapor) in footings, concrete floor slabs, and structural slabs, which greatly reduces fungus, mildew, and mold. It is especially useful under slabs overlaid with wood, tile, epoxy, and urethane coatings, carpeting, and resilient or seamless flooring systems, since it helps prevent warping and buckling caused by moisture migration.  PMPC also greatly reduces radon gas from entering the structure.



  • Offers a virtually impermeable vaporproofing system with a perm rating of less than 0.002 perms, the lowest in the industry.
  • As the only true vapor barrier for horizontal applications, it is both waterproof and vaporproof.
  • Provides excellent tensile strength and puncture resistance.
  • Helps prevent warping, buckling, or delamination of subsequent flooring systems.
  • Conforms to ASTM E1993-08 specification.
  • Greatly reduces fungus, mildew, and mold.
  • Greatly reduces radon gas from entering the structure.
  • Helps meet and maintain the maximum slab moisture transfer rate of 3 lb./1000 sq. ft./24 hours (1.45 kg/100 m²/24 hours), as allowed by the flooring industry’s specifications.

ASTM E1993 (2008)*
*Standard Specification for Bituminous Water Vapor Retarders used in Contact with Soil or Granular Fill under Concrete Slabs.



(1.22 m)
(2.44 m)
60 lb./100 ft.(27.22 kg)


Handling of PMPC is not critical because of its strength; however, it is advisable to stack sheets on smooth ground or a wood platform in storage or at the excavation site. This will eliminate the possibility of the material deforming or warping.



ASTM F1249

ASTM E154, Section 9

All technical data is typical information, but may vary due to testing methods, conditions, and operators.


Over 80% of moisture entering a structure originates in the site.  It moves from the grade into the structure both as a liquid (capillary) and as a gas (vapor). The only effective way to eliminate the costly problems of excessive moisture migration is to completely isolate the structure from the site during original construction with the installation of a true vapor seal membrane that is both waterproof and vaporproof. Material that is vaporproof is completely waterproof; however, not everything that is waterproof is vaporproof. PREMOULDED MEMBRANE VAPOR SEAL WITH PLASMATIC CORE is both waterproof and vaporproof.


While tremendously strong, even the best concrete is porous. Uncontrolled vapor will move through it, causing dank musty smells, rust, and condensation, damage to mechanical equipment, cracked plaster, chipped paint, efflorescence, warped floors, etc. The installation of a true vapor seal under the concrete floor slabs will stop moisture migration.


A true vapor seal must also be durable and tough enough to withstand normal handling, foot traffic, aggregate impact, and backfill abrasion. One tear or a few pinholes will destroy the entire purpose of the installation. Plastic films, laminated film, paper combinations, reinforced building papers, and saturated roofing felts are semi-permeable at best, and will permit the passage of air (vapor) through them.


PMPC offers the construction industry a positive, easy to install, economical, true vaporproofing system solution.


Wet insulating materials lose much of their R factor performance characteristics, reducing the energy efficiency of the structure. W. R. MEADOWS thermal and moisture protection products play a key role in maintaining the structure’s energy efficiency and aiding in the integrity of other structural systems, such as insulation.



When estimating the amount of PMPC required, figure the actual area plus 20% for overlap.



PMPC can be cut with a roofer’s or linoleum knife, using a straight edge.



Normally to facilitate bending at a change in plane, such as at corners or footings, a two-by-four can be used to make the bend.  In cold weather conditions, lightly heat the bending area and make the bend.



Pointing with POINTING MASTIC from W. R. MEADOWS should be done wherever an edge is exposed to prevent water from traveling under a sheet.


Horizontal Installation (On- or Below-Grade)

By installing PMPC on the ground prior to placing the concrete floor, moisture will be prevented from coming through the floor slab.  



In addition to the horizontal on- or below-grade application, PMPC can be placed on the intermediate structural slab, forming a “sandwich slab” installation. As a result, moisture is prevented from filtering downward from mechanical floors dedicated to heating and air conditioning equipment. This helps prevent damage to lower floor levels.


AdhesiveJoint MethodPer MSF of
 Membrane (Approx.)
Hot-Mop Asphalt*Complete400 – 500 lb. (180 – 230 kg)
PMPC TAPE**Butt-Joints/Overlap416 linear ft. (126.8 m)
POINTING MASTIC***Detail Strip, Edge Terminations2000 lineal ft./gal. (161.0 m/L)
*Based on minimum of 1/16″ (1.59 mm) film thickness
**Water Vapor Perm Rating is .0011
***1/8″ x 1″ x 200 lineal feet (3.18 mm x 25.4 mm x 60.96 m)


Application Method (Butt-Joint Method)

After the sheets are tightly butted together, remove the polyfilm from the joint area.  After removal of the polyfilm, center the PMPC TAPE over the butt joints and roll down with pressure for a positive seal.


Sealing Procedures

All protrusions through the concrete slab, such as sewer pipes, water pipes, and utility inlets, must have a positive seal between the protrusion and PMPC. Place a collar of PMPC at least 12″ (31 cm) larger than the protrusion around the protrusion. Seal in place with PMPC TAPE and point around the protrusion with POINTING MASTIC.



Joints in concrete surfaces should be addressed with MEL-PRIME.  MEL-PRIME is available in solvent-, water-based, and Northeast formulations.

Packaging: 1 Gallon (3.79 L) Units, 5 Gallon (18.9 L) Pails



Used for sealing top horizontal terminations or slab protrusions.
Packaging: 5 gallon (18.93 L) pails or 29 oz.

(857.65 ml) cartridges.



 A sturdy, self-adhering, reinforced tape of polymeric membrane that requires no additional adhesive. Tape is also made using the patented core material giving it superior WVT properties.  Provides a simple, easy, and economical method of effectively sealing horizontal and vertical butt joints. Each strip is nominally 6″ (152.4 mm) wide and 50′ (15.24 m) long. Has quick-strip release paper for ease of handling and application. Packaging: 6 rolls per carton.


Butt-Joint method of applying PMPC

Seal in place with PMPC


PMPC does not negate the need for relief of hydrostatic heads. A complete drain tile system should be placed on the exterior of the footing and, in severe cases, on the interior of the footing as well. If applied to concrete surfaces, repair any spalled areas, fill all voids and remove sharp protrusions.


Adhesive coverage ratios must be adjusted to compensate for surface irregularities and additional coats may be required to provide proper adhesion. For maximum concrete performance and durability, the floor slab concrete design should provide for the lowest possible slump and yet assure complete hydration of the concrete.