Gripset C-Plug

For active water leaks under pressure through holes, cracks, and openings in concrete and masonry, Gripset C-Plug forms an instant, non-shrink waterproof seal. This rapid-setting cementitious compound stops flowing water in underground car parks, basements, lift shafts, water tanks, and concrete pipes before curing to the mechanical strength of concrete.

How it works

C-Plug uses a rapid-setting, non-shrink chemical mechanism to expand slightly and lock into concrete or masonry cavities, blocking active water pressure. Hand-mixed and applied in small, individual batches, it goes from a paste to an initial set in under 60 seconds, allowing installers to hold back water flow manually until the seal is established. It does not contain additives that promote the corrosion of steel reinforcement, making it compatible with structural concrete repairs, subterranean joint filling, and the rapid anchoring of bolts, fixtures, and pipes.

Numbers that matter

• Initial set of under 1 minute: Provides the fast reaction window required to hold back active, pressurised water leaks by hand before the compound hardens.
• 8MPa compressive strength at 30 minutes: Reaches structural load-bearing capacity rapidly, preventing the plug from washing out under early hydrostatic pressure.
• 35MPa compressive strength at 28 days: Cures to a high-strength, durable repair that matches or exceeds standard structural concrete.
• 2-4 minute final set: Enables rapid successive placement when working from the outside in on large leaks, or when preparing joints for subsequent coatings.

Where to use it

• Water retention structures: Sealing water tanks, concrete pipes, culverts, and constructing pressure-resistant fillets at wall-to-floor junctions.
• Subterranean infrastructure: Stopping seepage in basements, cellars, underground car parks, lift pits, tunnels, power stations, and sewer systems.
• Joint filling: Filling joints between concrete segments in pipes, culverts, tunnels, and mines.
• Fixtures: Anchoring bolts, conduits, pipes, and sanitary equipment into dense concrete.

Limitations

• Expansion and movement joints: Do not use C-Plug as a sealant or filler over joints designed for structural movement.
• Substrate compatibility: Only suitable for cementitious surfaces; do not apply over non-cementitious substrates.
• Temperature limits: Do not apply over frozen surfaces. Ensure all concrete and masonry surfaces exposed to freezing conditions are completely free of ice. Cold temperatures will slow the curing rate.

Preparation and installation

Grind open cracks, joints, or holes to a minimum width and depth of 20mm. For high-volume leaks, increase the cut depth to a minimum of 40mm. Cut sides to a square or dovetail profile where possible, avoiding "V" profiles, smooth finishes, or feathered edges. Flush the area with clean water to remove loose debris, and ensure the substrate is thoroughly damp before application.

Mix by hand using a spatula or similar tool; do not use electric stirrers or paddle mixers. Limit batch sizes to a maximum of one handful (approximately 0.5kg of powder) per application, using approximately 150ml of clean 20°C water per 1kg of product. Once mixed to a putty consistency, press C-Plug firmly into the cavity using a gloved hand. Hold firm pressure until the initial set occurs (30 to 60 seconds), then slowly remove your hand. Keep the cured plug damp using a mist spray or damp sponge for 15 minutes after installation.

System detailing

To establish long-term protection against future dampness and negative water seepage in subterranean structures, coat the cured C-Plug with Gripset C-1P flexible cementitious membrane. For active leaks at wall-to-floor junctions, cut out the joint to a minimum 20mm width, pack with C-Plug, and form a 45-degree, 40mm wide cove at the junction before over-coating with the membrane.