Gripset BRW PF Square

For sealing leak control flanges, waste outlets, and joint intersections before waterproofing, Gripset BRW PF Square provides an instant moisture seal. This self-adhesive butyl rubber square sticks directly to the substrate and can be tiled, rendered, or coated over immediately, eliminating the drying time required by liquid detailing compounds.

How it works

The square utilises a high-tack butyl rubber backing combined with a fabric face. The butyl layer deforms around penetrations, PVC pipes, and metal flashings to absorb vibration and substrate flexing without rupturing. The fabric-faced top layer is compatible with cement-based finishes, tile adhesives, renders, and Gripset liquid waterproofing membranes, allowing you to maintain system continuity across the joint or flange.

Where to use it

• Puddle flanges and penetrations: Bridges the connection between the waste flange and substrates like concrete or compressed fibre cement sheeting.
• Metal repairs: Patches pinholes and pitted sections on galvanised iron, zincalume, copper, aluminium, and Colorbond surfaces before coating.
• Joint intersections: Works as a reinforcement bond breaker over movement-prone internal and external corners.
• Compatible substrates: Sticks to timber, plasterboard, masonry, plastics, polycarbonate, glazed surfaces, marble, granite, and ceramics.

Numbers that matter

• 250mm x 250mm x 0.8mm: Pre-cut dimension providing sufficient coverage to bridge flanges and adjacent floor substrates.
• 70% elongation at break (EN 12311-1): Accommodates joint movement and vibration in both longitudinal and transverse directions.
• >80N peel adhesion (ASTM D1000): High-strength mechanical bond prevents edge peeling under subsequent screeds and adhesives.
• 1.0N/mm² cement adhesion (EN 12004 – EN1348): High bond retention when using cement-based finishes like Gripset C-Bond adhesive over the fabric face.
• -40°C to 100°C service temperature: Resists thermal cycling from cold floors to hot pipes without losing adhesion or softening.

Installation and priming

On clean, stable, and dust-free non-porous surfaces like glazed tiles, PVC, metals, and dense concrete, BRW PF Square can be applied without a primer. Highly porous or dusty substrates must be primed first using Gripset GP, E60, or Xpress H20 Primer Plus.

To install, peel away the release paper from the butyl backing and press the square into place using a spatula, sponge, or cloth to eliminate air pockets. When sealing puddle flanges, cut an aperture in the centre of the square with a sharp knife to expose the waste pipe before applying your waterproofing membrane or tile adhesive.

Limitations

• Do not apply over damp surfaces. Substrates with residual moisture or rising damp must be sealed with Gripset E60 vapour barrier primer before application.
• Do not apply when surface temperatures are below 5°C or above 30°C.
• Not compatible with solvent-based materials applied directly over the square.
• Do not use as an exposed flashing or exposed joint seal in external applications; the square must be finished over with a surface covering.
• Not suitable for use as a trafficable surface or over active expansion joints.