Gripset 38FC

Gripset 38FC is a fast-curing, fibre-reinforced SBR latex waterproofing membrane for internal and external areas that will be covered by tiles, toppings or other approved finishes. Gripset lists recoat from about one hour, tiling or toppings from about four hours and flood testing from about 24 hours under standard conditions.

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Waterproofing and vapour barrier protection

38FC Membrane cures to form a durable, seamless elastomeric barrier that accommodates normal substrate movement without cracking. Formulated with fibre reinforcement for enhanced tensile strength and workability, the SBR latex formulation withstands continuously wet environments and ponding water without re-emulsifying. It functions as both a liquid vapour barrier and a waterproofing membrane when sandwiching between concrete substrates or applied under screeds, toppings, and tiles on balconies, decks, and bathroom floors.

Numbers that matter

• 4-hour tile-over time: Allows rapid progression to tiling with polymer-modified cement-based adhesives under standard conditions (23°C and 50% RH).
• 1-hour recoat window: Speeds up multi-coat application to horizontal and vertical surfaces.
• >300% Class III elongation: Meets AS 1145.3 high-elasticity standards to absorb movement across joints and sheet transitions.
• 1.0mm minimum dried film thickness (DFT): Achieved by applying 2 coats at a total minimum coverage of 1.5 litres/m² (750 microns WFT per coat) to ensure a reliable waterproofing barrier.
• 24-hour full cure: Enables rapid flood testing and early commissioning of the waterproofing system.

Where to use it

38FC Membrane is suitable for commercial, industrial, and residential applications on the following substrates:

• Concrete, render, and masonry
• Compressed fibre cement sheeting and plasterboard
• Wet area timber sheeting and external grade plywood
• Aerated concrete panels and blocks

Limitations

• Not to be used as a trafficable surface or left exposed to UV as a finished membrane.
• Do not apply to areas when rain is imminent.
• Do not apply when surface or ambient temperatures are below 5°C or above 30°C.
• Not to be used in areas subject to rising damp or negative hydrostatic pressure.
• All finish coatings applied over this membrane must be water-based and solvent-free.

Surface preparation and priming

Surfaces must be clean, dry, sound, and free of laitance, curing compounds, and contaminants. Concrete must cure for at least 28 days, and screeds or renders for at least 7 days. The membrane must be applied to primed surfaces using one of the following systems:

• Porous substrates: Gripset GP Primer applied at 1 litre per 8–10m².
• Non-porous substrates: Gripset OP Primer applied at 1 litre per 10m².
• Green or damp surfaces (residual moisture): Xpress Primer H2O Plus applied at 1 litre per 8m².
• Damp surfaces subject to rising damp: Gripset E60 applied in 1–2 coats at 1 litre per 3m² per coat (for mineral surfaces with >80% RH or >5% moisture content).

Detailing and system components

Before applying the overall membrane, all joints, junctions, penetrations, and cracks must be detailed:

• Joint transitions and bond breakers: Install Elastoproof B50 Joint Band bedded into a wet 150mm wide strip of 38FC Membrane, use self-adhesive BRW PF Tape, or apply a fillet of RLA Max SMP 25 sealant.
• Pipes and penetrations: Fit Elastoproof Collars into a wet coat of the membrane, seal with BRW PF Tape, or apply a bead of RLA Max SMP 25 sealant around the base.
• Static cracks (1mm to 6mm): Fill flush with RLA Max SMP 25 sealant and overlay with RLA Waterproofing Bandage, Elastoproof B50 Joint Band, or BRW PF Tape.