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High performance, water based, waterproofing membrane

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NEWFLEX™ Grey is a single-pack, water-based, non-hazardous liquid polymer specifically developed as a tough, durable and elastic waterproof membrane for wide application in the construction industry.

Product Uses

  • Exposed roofing applications (combined with TUFFCOTE™ Grey top coat for foot-traffic and longevity)
  • Podium slabs
  • Gutters
  • Balconies
  • Internal wet areas
  • Non-chlorinated ponds and water features

Features and Advantages

  • Single-pack, no mixing
  • Complies with Green Star requirements
  • Excellent adhesion
  • UV resistant
  • Easy application
  • Non-staining, low odour
  • Flexible, durable and waterproof

Physical Properties

Colour Grey
Composition Water based polymer
Service Temperature -10°C to +80°C
Elongation (AS1145) >320% Class III
Tensile Strength
>1.4 MPa
Density 1.3 g/m3 at 20°C


Substrates must be structurally sound, smooth, clean and dry. Remove all dust, laitance, loose matter, oil, curing compound, form release agents, or other contaminants.

Concrete should have a minimum strength grade of 25 MPa, and be moist-cured as required by AS 3600. Minimum age of concrete at time of waterproofing application should be 14 -28 days depending on concrete thickness and GCP primer being used.

Use SILCOR® LM PU Sealant to fill joints, cracks, gaps and form angle fillets to internal corners or penetrations. Allow minimum 24 hours of curing for sealant.



To dry substrates, internal wet area floors, walls, sills or flashings with moisture content below 5%, apply NEWFLEX™ Primer S at minimum 0.3 kg/m2. Maximum recoat time for NEWFLEX™ primers is 24 hours at 22°C. Use EPOCOTE™ F100W Clear at minimum 0.3kg/m2 as primer on green concrete, and substrates with moisture content below 10%. Maximum recoat time of EPOCOTE™ F100W Clear is 24 hours at 22°C. Roughen any stainless steel or PVC surfaces then wipe with Xylene to remove any dust or debris. Prime with EPOCOTE™ F 100W Clear at minimum 0.3kg/m2.


To joints, cracks, outlets, penetrations and bond-breaker fillets previously detailed with PU sealant, apply a brush coat of NEWFLEX™ Grey centred over detail area at approximately 1.0mm WFT (wet film thickness).

Application of Continuous Membrane

Within 24 hours of priming, apply NEWFLEX™ Grey liberally by brush or roller in two or more coats to required minimum membrane thickness – see Coverage section.

Allow to dry between coats and to be fully cured a minimum 48 hours before flood testing, covering with mortar bed or tiling. Cure time may be extended during winter or in areas of poor ventilation.


All installation work is to be done fully in accordance with the NCC and requirements of AS3740 and AS4654.

  • Seal all external joints in cement and timber sheet or other movement joints, penetrations, etc with 100mm PE Reinforcing Fabric embedded between two wet-on-wet coats of NEWFLEX™ Grey at 0.5 litre/m2 – allow to dry.
  • If any reinforcing fabric is used in association with NEWFLEX™ Grey, it is recommended that the fabric is embedded between two heavy coats of standard NEWFLEX™ Grey. Roll vigorously into and through the fabric to totally saturate it giving a homogeneous, dense coating structure.
  • In hot weather, up to 10% clean water may be added to aid application


NEWFLEX™ Grey may be subjected to light applicator foot-traffic 24 hours after installation, but is not for use as a trafficable membrane. Use the following surfacing systems only after NEWFLEX™ Grey membrane system has fully-cured.


Ceramic tiles may be laid on a mortar bed or other appropriate adhesives or directly to the cured membrane. Ensure expansion joints are used.


Prior to installing backfill or landscaping, ensure system is fully-cured then cover with PROTECTOBOARD™ or RAPID-DRAIN™ membrane protection.

Other Rigid Surfaces

Use two layers of 250 micron slip-sheet under concrete toppings.

Decorative Coatings

Water-based paints and acrylic-based texture coatings may be applied directly to NEWFLEX™ Grey membrane.


Internal Wet Areas

Floors – minimum 2.1 kg/m2 to give a minimum 1.6mm total Wet Film Thickness (WFT) and minimum 1.0mm total Dry Film Thickness (DFT) Walls – minimum 1.5 kg/m2 to give a minimum 1.2mm total WFT and minimum 0.7mm total DFT


Water features, balconies and tanking apply at 2.6 kg/m2 to give a minimum 2.0mm total WFT and minimum 1.25mm total DFT Window or door reveals – apply at 2.1 kg/m2 to give a minimum 1.6mm total WFT and minimum 1.0mm DFT

Required application rates for specific projects may be higher or lower, dependent on structural design, area of application, project specification and product warranty period required. Please contact your local GCP representative or the GCP Technical Department for information specific to your project estimating requirements.


  • NEWFLEX™ Grey 18.75kg (packed in 15-litre pails)
  • NEWFLEX™ Primer S 18kg (packed in 20-litre pails)
  • EPOCOTE™ F100W Clear 20 litre and 4 litre sets

Shelf Life

Unopened pails of NEWFLEX™ Grey stored in a dry, cool place have a shelf life of 12 months.


Remove uncured product with water. Solvent may assist with the removal of cured product. Exercise care when using solvents. Review Material Safety Data Sheet (MSDS) before use.

Health and Safety

In case of spills and accidents, refer to the MSDS of the products or when in doubt contact your local GCP representative.

Always wear protective clothing, gloves and protective goggles when handling chemical products.

For full information, consult the relevant MSDS.


Information contained in this document does not cover all possible application scenarios or imply product suitability for an application. Please contact your local GCP representative or the GCP Technical Department for further information.


GCP and contractors recognised by GCP as experienced in the application of GCP products will provide product warranties for individual projects. Product warranty periods offered are dependent on project details and complexity. Requests for very long product warranty periods may necessitate increased membrane thicknesses to ensure longevity. Contact your local GCP representative for further details.


Release Date: 02/11/18. The information contained in this product data sheet supersedes all previous versions.

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