Gripset BRW HD

Gripset BRW HD is a self-adhesive butyl-rubber sheet membrane with an HDPE face for protected structural waterproofing. Its cold-applied system provides immediate sealing for retaining walls, basements, planter boxes, roof gardens, podiums and under-pedestal systems and must be protected from long-term UV exposure.

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How it works

BRW HD uses a high-tack butyl backing that bonds directly to porous masonry and concrete or non-porous metal and plastic surfaces. This chemical configuration eliminates the safety hazards of solvent-based adhesives and the burn risks of torch-on bitumen membranes, while preventing the bleeding or yellowing common with traditional asphalt sheets. It handles continuously ponding water in roof gardens, planter boxes, and plaza decks. To ensure watertight continuity, each roll features an in-built sealing strip along the sheet edge for reliable lap joint sealing.

Numbers that matter

• Class III membrane: High elasticity and elongation capacity (<300% to AS1145.3) to absorb structure settling and ground vibration in basement walls and retaining systems without cracking.
• >3MPa tensile strength: Tested to AS 4654.1 Appendix A, providing the puncture, tear, and impact resistance needed to survive backfilling and screed placement.
• -30°C to 80°C service temperature: Maintains structural stability and rubber flexibility across extreme thermal cycles without losing adhesion or becoming brittle.
• 1g/24h/m² water vapour transmission: Tested via ASTM E96 (desiccant method) to prevent moisture vapour migration through subterranean concrete walls.
• 0mm drying time: Self-adhesive backing seals instantly on contact, eliminating the standard 24-to-48-hour cure window of liquid-applied membranes.

Where to use it

This membrane is suitable for installation over concrete, sand-cement screeds, concrete block, masonry, compressed fibre cement sheeting, structural plywood, and timber sheeting. It also bonds without primer to non-mineral surfaces, including:

• Most metals such as galvanised iron, zincalume, stainless steel, copper, and aluminium.
• Glazed surfaces, ceramics, marble, and granite.
• Soft and rigid plastics, PVC, and DPC films.
• Existing epoxy coatings.

Limitations

• Must not be used for applications subject to direct, permanent UV exposure. Under pedestal paver finishes, it must be completely covered and protected from sunlight.
• Not suitable as a trafficable surface.
• Do not apply over expansion joints.
• Do not use for applications required to support direct-stuck tiles, screeds, paints, or other decorative coatings. For applications requiring direct-stick finishes, refer to the BRW PF Tape TDS and the BRW Installation Manual for capping details.

System priming and preparation

While priming is generally not required for clean, prepared metals, plastics, and glazed surfaces, mineral substrates must be primed according to the site conditions:

• Porous and absorbent surfaces: Prime with Gripset GP Primer at a minimum coverage rate of 1 litre per 8–10m².
• Non-porous and non-absorbent mineral surfaces: Prime with Gripset OP Primer at a minimum coverage rate of 1 litre per 12m².
• Green, damp surfaces or external floors: Apply 1 to 2 coats of Gripset E60 at a minimum coverage rate of 1 litre per 3m² per coat.
• Cure times: New concrete must cure for at least 28 days; cement renders and sand-cement screeds must cure for at least 7 days before application.

Installation detailing

• Vertical and side overlaps: Align sheets using the guide lines, remove the release tape from the integrated sealing strip, and press firmly with a handheld vinyl roller to fuse the butyl backing.
• Horizontal and roll-end joins: Apply BRW FG Tape centrally over the joint line. Overlap the bottom roll 25mm onto the tape, then overlap the starting roll 300mm over the existing sheet as marked by the perforated squares. Roll firmly to seal.
• Wall and floor intersections: Detailed wall/floor junctions require BRW HD Tape. Center the tape over the joint, returning half up the wall and half onto the floor sheet with a minimum 50mm overlap.
• Planter boxes: Where vertical wall sheets overlap onto floor sheets, maintain a minimum overlap of 150mm.
• Penetrations and floor wastes: Cut a "+" aperture to slide sheets tightly over pipes and fixtures, rolling the edges firmly. Bridge the interface between the substrate and leak control flanges before cutting out the waste opening.