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PRECON®
Blindside/Underslab Membrane
DESCRIPTION
PRECON is a composite sheet membrane comprised of a non-woven fabric, elastomeric membrane, and W. R. MEADOWS’ exclusive, patented plasmatic core (U.S. Patent No. 7,179,761). The plasmatic core is a seven-layer matrix designed for toughness and provides the lowest water vapor transmission (WVT) rating on the market. Once concrete is poured against PRECON and the concrete cures, a mechanical bond forms that secures the concrete to the membrane.
USES
PRECON is used as a blindside membrane in vertical applications where access to the positive side is limited. The membrane can also be used for horizontal applications for underslab waterproofing and vaporproofing.
FEATURES/BENEFITS
- Provides a waterproof seal between the membrane and poured concrete wall.
- Helps prevent moisture migration into the structure.
- Acts as a barrier against termites.
- Reduces methane and radon gas intrusion.
TECHNICAL DATA
| Property | Test Method | PRECON Results |
| Color | Black | |
| Thickness | ASTM D 1000 | 73 mil (1.85 mm) |
| Low Temp Flexibility | ASTM D 1970, 180° @ -25° F (-32° C) | Pass |
| Resistance to Hydrostatic Head | ASTM D 5385-93 | 230′ (70 m) |
| Elongation | ASTM D 412-06 | > 400% |
| Tensile Strength, Film | ASTM D 882 | 9200 psi (63.4 MPa) |
| Crack Cycling | ASTM C 836 @ -15° F (-36° C) | Pass |
| Puncture Resistance | ASTM E 154 | > 210 lb. (> 934 N) |
| Peel Adhesion to Concrete | ASTM D 903 | 10 lb./in (1754 N/m) |
| Moisture Vapor Transmission | ASTM E 96B | 0.0011 perms |
| Resistance to Penetration by Termites | Texas A&M Method Percentage of Penetration | 0.0% |
| Resistance to Penetration by Pesticides | ASTM F 2130 Percentage of Penetration | 0.0% |
| Resistance to Fungi in Soil | GSA-PBS 07115 – 16 Weeks | No Effect |
| Minimum Application Temperature | 0° F (-18° C) |
PACKAGING
4′ (1.2 m) wide x 50′ (15.2 m) long rolls, one roll per carton.
STORAGE AND HANDLING
Store membrane cartons on pallets and cover if left outside. Keep materials away from sparks and flames.
APPLICATION
Surface Preparation … Inspect all surfaces for any conditions detrimental to the proper completion of the work. Surfaces should be structurally sound. Remove debris or any other foreign material that could damage the membrane.
Application Method … In vertical applications of PRECON, mechanically attach with fasteners every 12″ (31 cm) across the top, within ½” (13 mm) of the top edge of the membrane. Install the membrane with the fabric side facing toward the concrete pour.
Prior to application of the blindside membrane, attach MEL-DRAIN™ rolled matrix drainage system from W. R. MEADOWS to lagging or soil retention system.
Remove release paper on 4″ (102 mm) overlap. Apply membrane and roll press into place with a tile type roller.
End Laps … Overlap membrane 3″ (76.1 mm). Prior to overlap, apply POINTING MASTIC from W. R. MEADOWS in area to be lapped. Roll press membrane into POINTING MASTIC. At terminations of membrane, apply 12″ (305 mm) wide area of PRECON FABRIC TAPE with 6″ (152 mm) on each side of lap edge. For best results, use MEL-PRIME™ adhesive over 12″ (305 mm) area prior to application of tape.
Penetrations and Protrusions … Detail around all horizontal and vertical penetrations using MEL-ROL® LIQUID MEMBRANE (two-component) from W. R. MEADOWS. Apply MEL-ROL LIQUID MEMBRANE by forming a fillet around the pipe or protrusion, overlapping the fabric side of PRECON and the protrusion a minimum of 2 ½” (64 mm). If the gap between the protrusion and the membrane is greater than ½” (13 mm), apply PRECON FABRIC TAPE over the fully-cured MEL-ROL LIQUID MEMBRANE (minimum 24 hours cure required). All penetration and protrusion surfaces must be clean, rust-free, and sound prior to application of MEL-ROL LIQUID MEMBRANE.
For horizontal applications involving a cluster of penetrations, consider the use of MEL-ROL LM single-component membrane. Prior to application of MEL-ROL LM, prepare the surfaces of the penetrations as above and provide a block out using 2′ x 4′ (0.6 x 1.2 m) lumber or other in order to create a “pitch pan” area to receive MEL-ROL LM.
Patching … Prior to pouring, inspect membrane for punctures or damage and repair as necessary with POINTING MASTIC and/or PRECON FABRIC TAPE.
Underslab Application … Refer to ACI 302.1R.17 for sub-grade preparation prior to PRECON placement.
PRECAUTIONS
Concrete should be poured within 60 days of membrane installation. For installations below 32° F (0° C), contact W. R. MEADOWS technical services. When using bar supports, use those with a flat bottom.
LEED INFORMATION
May help contribute to LEED credits:
- EA Credit 1: Optimize Energy Performance
- IEQ Credit 3.1: Construction Indoor Air Quality Management Plan: During Construction
- IEQ Credit 7.1: Thermal Comfort – Design
- MR Credit 2: Construction Waste Management
- MR Credit 5: Regional Materials
Material last updated August 2012.
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