Gripset Xpress Multi Pro Membrane

Gripset Xpress Multi Pro is a fast-cure, water-based elastomeric waterproofing membrane for exposed and under-tile applications. It is designed to resist early rain and ponding, remain stable in permanently wet conditions after cure and provide a UV-resistant, light-foot-trafficable finish on suitable external areas.

Compare waterproofing systems: Browse the full waterproofing membrane range to compare liquid, sheet, cementitious and trafficable systems. For this format, also compare our trafficable waterproofing membranes. Always match the membrane to substrate, exposure, movement, immersion, traffic and finish requirements.

How it works

Xpress Multi Pro Membrane uses rapid-drying technology to form a rain-resistant finish within 3 hours. It withstands early ponding water and permanently wet conditions without blistering or re-emulsifying. This water-based, solvent-free formulation exhibits high elasticity to bridge joints and junctions under constant weathering, preventing moisture ingress into sub-floor structures.

For projects with critical handovers, using this membrane alongside Xpress Primer H2O Plus allows fast priming over green concrete or damp mineral substrates containing residual moisture.

Where to use it

• Roofs: Suitable as an exposed, light-foot-trafficable membrane finish, or to be covered over with screeds and toppings.
• External structures: Balconies, decks, podiums, terrace floors, and parapets exposed to constant weather and UV.
• Internal wet areas: Bathrooms, laundries, and general tiled areas to prevent moisture ingress.
• Compatible substrates: Concrete, render, masonry, compressed fibre cement sheeting, plasterboard, wet area timber sheeting, external grade plywood, and aerated concrete panels or blocks.

Numbers that matter

• 3-hour rain resistance: The membrane resists early washouts and early ponding water within 3 hours of application under normal conditions (23°C and 50% RH).
• 1 to 2-hour recoat window: Allows multi-coat applications to proceed quickly on-site to build required film thickness.
• 24-hour full cure: Safe for flood testing or tiling over within 24 hours under standard drying conditions.
• >300% Elongation (Class III, AS 1145.3): High elasticity to accommodate structural movement without cracking or tearing the cured film.
• >1MPa Tensile Strength (AS 1145.3): Mechanical resistance to withstand light foot traffic and subsequent topping installations.
• 6g/m²/24 hours Water Vapour Transmission (ASTM E96): Low vapour permeability to restrict moisture vapour moving through the substrate.

Required coverage

Always verify wet film thickness during application using a wet film gauge to ensure compliance with the following minimum performance floors:

• Under-tile applications: Minimum of 2 coats at a total coverage of 1.5 litres/m² to achieve a minimum 0.8mm dried film thickness (DFT).
• Exposed, trafficable membrane: Minimum of 3 coats at a total coverage of 2.0 litres/m² to achieve a minimum 1.0mm dried film thickness (DFT).

Substrate preparation and priming

All surfaces must be clean, sound, dry, and free of laitance, curing compounds, and contaminants. Grind or abrasive-blast structurally unsound layers. Concrete must cure for 28 days; cement renders and screeds must cure for 7 days. Select and apply the appropriate primer before membrane installation:

• Porous/absorbent surfaces: Gripset GP Primer applied at 1 litre per 8–10m².
• Non-porous surfaces: Gripset OP Primer applied at 1 litre per 12m².
• Green/damp surfaces with residual moisture: Xpress Primer H2O Plus applied at 1 litre per 8m².
• Rising damp (>80% RH ASTM F2170 or >5% moisture ASTM F2659): Gripset E60 applied in 1–2 coats at 1 litre per 3m² per coat.

Detailing and joint preparation

All joints, junctions, movement zones, penetrations, and cracks must be sealed prior to membrane application:

• Bond breakers (AS 3740 & AS 4654.1): Install Elastoproof B50 Joint Band embedded into a wet first coat of membrane, lay BRW PF Tape centrally over the joint, or install a sealant fillet using RLA Max SMP 25.
• Pipes and penetrations: Fit Elastoproof Collars into the wet membrane, construct flanges using BRW PF Tape, or apply a bead of RLA Max SMP 25 sealant.
• Static cracks (1mm to 6mm) and screw/nail holes: Clean, fill flush with RLA Max SMP 25, and overlay with RLA Waterproofing Bandage, Elastoproof B50 Joint Band, or BRW PF Tape.

Tiling and topping integration

• Direct tiling: Must be performed using polymer-modified cement-based adhesives such as Gripset C-Lite, C-Mastic, or C-Rubber. Tiling must comply with AS 3958.
• Screeds and toppings: Incorporate Gripset 11Y as a bonding agent and water-resistant additive in the mix, or use Gripset C-Bed engineered screed.

Limitations

• Do not apply to areas when rain is imminent.
• Do not apply when the surface temperature is below 5°C or above 30°C.
• Do not use in areas where solvent or petroleum-based products may be spilled.
• Do not use in areas subject to negative hydrostatic pressure.
• All finish coatings applied over this membrane must be solvent-free.