Protecting underground and external structures from persistent moisture, corrosion, and rot demands a proven solution. When specifying an economical, reliable membrane that offers both robust waterproofing and durable protective coating, Gripset 51 provides the flexibility and adhesion needed. It ensures critical assets remain sealed and sound against the elements.

Why this product exists

Gripset 51 is formulated as a versatile, solvent-free bitumen-rubber liquid membrane. It exists to provide a flexible and economical solution for challenging underground and external waterproofing jobs. This product excels at forming a seamless barrier that withstands continuous damp conditions and acts as a long-lasting protective coating against corrosion, rot, and salt damp on timber and metal surfaces.

The numbers that matter

  • Flexibility: An elongation of over 500% (Class III to AS1145.3) means Gripset 51 offers significant movement capability. This flexibility is critical for bridging minor cracks and accommodating normal substrate movement, preventing membrane failure in dynamic environments like retaining walls or underground structures.
  • Water Resistance: With a water absorption rate of just 1.6% (AS 3558.1) and low water vapour transmission (1.2 g/m²/24 hours), Gripset 51 reliably stops moisture ingress. This directly translates to effective protection against dampness and hydrostatic pressure in subterranean applications.
  • Adhesion and Durability: The membrane cures to a Shore A Hardness of 52 and a tensile strength greater than 2 MPa. This provides a tough, adherent layer that withstands external pressures and provides a durable protective shield for buried structures and exposed components.

What it's like to use

Gripset 51 is applied by brush or medium nap roller, with a minimum of two coats. Achieving the specified 1.0 mm dry film thickness is crucial; a wet film gauge helps regulate coverage. For effective application, prepare surfaces by ensuring they are clean, sound, and free from contaminants. Porous surfaces require priming with a 1:3 diluted mix of Gripset 51 and water, while non-porous surfaces use a 1:1 dilution, or Gripset OP Primer. For mineral surfaces with residual moisture or rising damp, Gripset E-60 Primer acts as a suitable primer.

The product has a recoat time of 2-4 hours, allowing efficient multi-coat application. Backfilling can occur after 5 days, with full cure achieved in 10 days for flood testing or full service. Wet product cleans up with water; dried material requires mechanical removal.

Gripset 51 can also be mixed with a 3:1 sand-cement mortar for high-build applications like forming waterproof fillets in planter boxes (1 part Gripset 51 to 1 part mortar). For low-build applications that enhance filling properties or accelerate drying in colder conditions, a 3 parts Gripset 51 to 1 part mortar mix is used.

Where this product excels

  • Waterproofing Retaining Walls and Underground Structures: Forms a flexible, crack-bridging membrane for external retaining walls and subterranean surfaces. It creates a continuous 1.0 mm dry film thickness barrier, crucial for long-term moisture protection in environments like external cellar and basement walls.
  • Protective Coating for Metal and Timber: Provides robust protection against corrosion, rot, and salt damp for exposed building components like timber posts or galvanised iron. This extends their service life in demanding outdoor conditions.
  • Lining Planter Boxes and Garden Beds: Resists root moisture penetration in external planter boxes and garden beds. It can be integrated with mortar fillets at wall/floor junctions for comprehensive waterproofing in landscaping applications.
  • Gutter Repairs and Bitumen/Asphalt Restoration: Bonds effectively to aged bitumen and asphalt surfaces. This makes it an efficient solution for gutter repairs or restoring the integrity of existing waterproofing systems without requiring a full strip-out.

How it fits in a real system

Gripset 51 is typically applied as the primary waterproofing layer or protective coating in external and underground systems. Its position requires careful attention to detailing at critical points. For pipes and penetrations, ELASTOPROOF COLLARS are fitted into a wet coat of Gripset 51. Alternatively, BRW PF TAPE can form flanges, or RLA MAX SMP 25 sealant can seal around the base of penetrations. For static cracks up to 6mm, RLA MAX SMP 25 sealant fills the crack, reinforced with strips of RLA Waterproofing Bandage or Elastoproof B50 Joint Band. Bond breaker systems like ELASTOPROOF B50 JOINT BAND or BRW PF TAPE are encapsulated within two coats of Gripset 51 at joints and junctions, ensuring continuous flexibility and waterproofing performance.

Choose this when

  • You need economical, flexible waterproofing for underground structures: Such as external retaining walls, cellar walls, or basement exteriors, where continuous damp conditions are expected.
  • Protecting external timber or metal components: To guard against corrosion, rot, or salt damp, extending their service life in exposed environments.
  • Lining external planter boxes or garden beds: Where resistance to root moisture and a flexible, impermeable barrier are essential.
  • Repairing aged bitumen or asphalt coatings: Its ability to bond with existing bituminous surfaces makes it suitable for cost-effective remedial work on gutters and other weathered surfaces.

Don't use this when

  • Not for: Trafficable surfaces or areas requiring a direct finish of tiles, renders, screeds, or paints. The membrane is not designed to be walked on or directly covered in this manner.
  • Not for: Immersed applications like ponds or internal wet areas subject to continuous water contact. For general wet area waterproofing, consider products like Everflex Aqua-Ban Waterproofing Membrane.
  • Not for: Expansion or control joints where a specific sealant is required. This product is a membrane, not a dedicated joint sealant.
  • Not for: Areas with rising damp or negative hydrostatic pressure. Its formulation is for positive side waterproofing; dedicated systems are required for negative pressure conditions.
  • Not for: Exposed roof membranes where UV stability and specific traffic requirements are paramount. For exposed roof applications, consider products like Everflex WPUV UV-Stable Waterproofing Membrane.

Choosing between bitumen-rubber and cementitious membranes

Gripset 51 offers a flexible, bitumen-rubber solution for demanding underground and external waterproofing, and heavy-duty protective coating tasks. It delivers excellent sealing and adhesion across various building surfaces, especially where continuous damp conditions or corrosive environments are a concern. In contrast, products like Gripset C-1P Waterproofing Membrane provide a different chemistry, typically favouring masonry and concrete substrates, often for under-tile applications or where a rigid, breathable system is preferred. Gripset 51 is explicitly not for trafficable finishes, immersed applications, or internal areas requiring direct tiling or other surface finishes, making its application focus distinctly external and protective.