Collection: Repair, Grouts & Patching

Structural repairs restore the strength and load-bearing capacity of the substrate using high-performance mortars like Mapei Planitop R4 or Planitop Fast 330. Cosmetic repairs are for surface defects only — small pits, edge chips, or aesthetic touch-ups — and typically use lightweight patching mortars. Always identify whether the damage is superficial or structural before selecting a product.

All weak, contaminated, or loose material must be mechanically removed until clean, sound concrete is exposed. The surface should have a rough, open texture (not polished) to ensure mechanical keying. Remove laitance, rust, oil, and dust. If patching over reinforcement, clean steel to bare metal and prime with a corrosion inhibitor like Mapefer 1K.

Most cement-based repair mortars should be applied to saturated surface-dry (SSD) substrates — damp but without standing water. This prevents suction that would draw moisture out of the repair mix and ensures strong adhesion. However, resin-based products like epoxy mortars require dry surfaces. Always check the TDS for moisture tolerance before application.

Allow the repair mortar to cure until fully hardened and dimensionally stable — typically 24–48 hours for rapid-setting mortars and up to 7 days for standard mortars. If applying a waterproofing membrane, confirm there’s no residual shrinkage movement or surface carbonation. Applying too early can lead to cracking, loss of bond, or trapped moisture under the membrane.

Only if the crack is static and non-moving. For live or moisture-bearing cracks, use epoxy or PU injection to seal and stabilise them before patching the surface. Filling active cracks with rigid mortar will only mask the issue — the crack will reappear once movement continues.

Rigid mortars (like Planitop R4) are designed for structural concrete where movement is minimal. Flexible mortars or polymer-modified options (such as Planitop Fast 330) offer minor strain accommodation, making them suitable for transition areas or thin surface repairs before membrane application. The choice depends on whether the area will experience vibration, thermal cycling, or flex.

Because any contamination, laitance, or unbonded patch will compromise the adhesion of your membrane system. Repairs should always be finished flush, clean, and fully cured. If repairs are coarse or porous, prime them with a compatible acrylic or epoxy primer before membrane installation. The repair layer is the foundation of the waterproofing system — if it fails, the entire build fails.

Spalling occurs when carbonation or chloride ingress causes reinforcement to corrode and expand. To fix it:

1. Remove all delaminated concrete and expose corroded reinforcement.
2. Clean rust back to bright metal using wire brush or sandblast.
3. Prime with Mapefer 1K or equivalent corrosion inhibitor.
4. Rebuild with Planitop R4 or a structural repair mortar compatible with the substrate.
Once cured, apply a compatible primer and waterproofing system such as Planiseal MR + Mapelastic Foundation.

Key principle: Stop corrosion first, then rebuild the structure. Don’t just cover over it.

Yes — rapid-setting or polymer-modified mortars like Planitop Fast 330 or Nivorapid can be used to create screed falls or slope corrections before membrane application. Ensure the surface is keyed and primed to prevent debonding. Allow full cure and lightly sand if a smooth trowel finish forms, as waterproofing membranes bond better to slightly open textures.