Sika Damp-Proofing Slurry 25kg

Sika Damp-Proofing Slurry is a one-part, cement-based waterproof coating and damp-proofing slurry. It is supplied as a powder that is mixed with water on site to produce a slurry or thin mortar coating. Once applied and cured, it forms a rigid, water-resistant barrier that can be used for tanking basements, waterproofing concrete and masonry structures, and lining water-retaining structures. Because it is cement-based rather than membrane-based, it bonds directly to the substrate rather than relying on adhesion to a surface film, making it suitable for situations where hydrostatic pressure is a consideration.

Sika Damp-Proofing Slurry is suitable for a range of waterproofing and damp-proofing applications, including:

• Waterproof coating for tanking residential and domestic basements
• Internal damp-proofing and waterproofing of basement and cellar walls and floors
• Interior and exterior damp-proofing of basement walls in new builds and existing structures
• Interior and exterior waterproofing of concrete, renders, brickwork and blockwork
• Thin-layer mortar or slurry coating and lining
• Lining of water tanks, pools, planters and other water-retaining structures

Always check the current Technical Data Sheet to confirm suitability for your specific application before use.

Sika Damp-Proofing Slurry is typically applied in two coats to achieve the required coating thickness and a continuous, pin-hole-free barrier. The first coat should be allowed to reach initial set before the second coat is applied. The product can be applied by brush, trowel or sprayer depending on the substrate and application method – full guidance for each method is provided in the Technical Data Sheet. The substrate must be sound, clean and free from dust, oil, grease and loose material before application. Pre-wetting the substrate is generally recommended to reduce suction and improve adhesion – check the TDS for specific preparation requirements.

Sika Damp-Proofing Slurry is designed to resist water penetration and can be applied to resist negative water pressure (water pressing from the outside through the structure). This makes it suitable for internal tanking applications where water is pushing against the face being coated – a common requirement in basement waterproofing. For positive water pressure applications (water pressing directly onto the coated face), the product can also be used, but coverage, coat thickness and substrate preparation become especially important. Check the Technical Data Sheet for the specific pressure resistance ratings and confirm suitability with the manufacturer or a waterproofing specialist if the project involves high hydrostatic pressure.

The pot life of Sika Damp-Proofing Slurry is approximately 30 minutes at +20°C. In warmer conditions, pot life will be shorter, so mixed material should be used promptly and not allowed to begin setting before application is complete. Application should not be carried out in temperatures below +5°C, as low temperatures significantly slow curing and can affect performance. Avoid applying in direct sunlight or strong wind where rapid drying could cause surface cracking – damp curing the applied coating in hot or dry conditions is advisable. Always refer to the current TDS for full temperature and environmental guidance.

No. Sika Damp-Proofing Slurry does not provide a trafficable finish once cured. It is a protective waterproofing coating, not a wearing surface. If a floor is being treated, a levelling screed should be applied over the cured slurry before the floor is put into use or any floor finish is laid. This is standard practice in basement tanking where the slurry is used on the floor slab.

Curing times will depend on temperature, humidity and the number of coats applied. At +20°C, the product will typically reach initial set within a few hours, but full cure and the ability to apply subsequent finishes, screeds or floor coverings requires longer – check the current Technical Data Sheet for specific overcoating and re-entry times. In cooler or more humid conditions, curing will take longer. Rushing subsequent work before sufficient cure can compromise the waterproofing performance of the system, so it is worth allowing adequate time before loading the surface or applying finishes.