Gripset XpressLay

Gripset XpressLay is a high-strength, reinforced self-adhesive PVC underlay combining waterproofing, anti-fracture and decoupling functions for internal wet-area floors and tiled substrates. Its cold-applied sheet format is designed for rapid installation over suitable concrete, timber, fibre-cement, tile and other approved surfaces.

Why choose XpressLay? Its reinforced PVC sheet combines waterproofing with anti-fracture and decoupling functions on suitable tiled floors. For a fibre-faced butyl waterproofing sheet under compatible floor finishes, compare BRW PFN. Both need the specified adhesive, junction detail and finished floor covering.

How it works

XpressLay is a 1mm thick, reinforced PVC sheet backed with a high-tack adhesive. The sheet bonds directly to the floor substrate, isolating the finished tile bed from subfloor stress. Its high tensile strength (exceeding 2MPa) and Class II elongation allow it to absorb vibration, movement, and flexing in timber sheeting, structural plywood, and cracked concrete before these forces reach the tile layer. The self-adhesive backing makes it suitable for application in cold and humid environments where liquid membranes struggle to dry, establishing a reliable moisture barrier with a water vapour transmission rate of just 0.1g/24h/m².

Numbers that matter

• >2MPa tensile strength (AS 4654.1 Appendix A): High mechanical resistance to physical rupture, tearing, and subfloor movement.
• >60% elongation (AS1145.3): Class II elasticity to bridge non-structural subfloor cracks and resist vibration without tearing.
• 0.1g/24h/m² water vapour transmission (ASTM E96): Restricts vapour transmission, protecting timber underlays and sensitive floor finishes from rising moisture.
• 1.5% water absorption (AS 3558.1): Low water absorption performance to maintain structural integrity under persistent wet area conditions.
• -30°C to 80°C service temperature: Maintains structural stability and performance across extreme temperature shifts.

Where to use it

XpressLay is suitable for commercial, industrial, and residential applications on the following substrates:

• Concrete and screeds.
• Compressed fibre cement sheeting.
• Timber sheeting and structural plywood (functioning as a tile underlay alternative).
• Glazed surfaces, marble, granite, and ceramics (for tiling over existing tiles).
• Soft and rigid plastics, PVC, and DPC films.
• Over existing epoxy coatings, vinyl, or aged industrial floor coatings.

Limitations

• Suitable for floor and horizontal surfaces only. Do not use on vertical surfaces to support tiles or other finishes.
• Suitable for internal applications only. Do not use externally.
• Do not apply when surface or ambient temperatures are below 5°C or above 30°C.
• Not to be used as an exposed membrane finish; it must be finished over.
• Not to be used as a trafficable surface.
• Do not apply directly over expansion joints.
• Not compatible with solvent-based finishes applied over the membrane.
• Concrete substrates must be cured for at least 28 days; cement render and sand-cement screeds must cure for at least 7 days.

Installation and priming

All substrates must be clean, sound, smooth, dry, and free from contaminants. Gripset XpressLay must be applied onto primed surfaces. Priming is generally not required for non-porous, non-mineral surfaces like plastics and glazed surfaces when they are prepared, sound, and clean.

• Porous substrates: Prime with RLA Universal Primer diluted 1 part primer to 2 parts water. Apply one coat at a coverage rate of 1 litre per 5–10m².
• Non-porous substrates (mineral-based): Prime with undiluted RLA Universal Primer. Apply one coat at 1 litre per 5–10m².
• Green or damp surfaces: Apply 1 to 2 coats of Gripset E60 by brush or roller at a minimum coverage of 1 litre per 3m² per coat.

Detailing, joins, and tiling

To establish a continuous waterproofing or anti-fracture layer, follow these application requirements:

• Overlaps: All horizontal and vertical sheet joins must have a minimum 50mm overlap, pressed firmly with a hand-held vinyl roller. For waterproofing applications, coat all overlaps with a 100mm wide coat of a suitable Gripset liquid under-tile membrane applied centrally across the joint. No liquid coating is required on overlaps when used solely as an anti-fracture system in dry areas.
• Wall/floor junctions: Detail critical corner intersections after sheet installation using either Elastoproof B50 Joint Band embedded in a suitable Gripset liquid under-tile membrane, or self-adhesive BRW PF Tape sealed with a liberal coat of the liquid membrane.
• Penetrations and floor wastes: Slide the cut sheet over pipes and seal with Gripset liquid membrane, or use Elastoproof Collars or BRW PF Tape. For floor wastes, seal the interface between the sheet and the waste flange using BRW PF Squares before making the final centre cut.
• Tiling: Direct tiling over XpressLay requires polymer-modified cement-based adhesives, such as Gripset C-LITE, C-MASTIC, or C-RUBBER. For other adhesives, contact RLA Polymers to verify compatibility.
• Screeds and toppings: If applying a screed, render, or concrete topping over XpressLay, incorporate Gripset 11Y as a proprietary bonding agent and water-resistant additive in the mix, or use Gripset C-BED engineered screed.