Swimming pools, water tanks, fish ponds and other water-retaining structures are exposed to water for long periods. Once the surface finish becomes hollow, cracked or deteriorated, simply applying another layer on top may only hide the problem temporarily. For long-term leakage repair, the damaged finish should be removed first so the waterproofing system can bond directly to the original concrete or masonry substrate.
This CKS Solution Series article explains how to repair pool and water tank leakage after removing the damaged finish, using a system of CKS Primer and Aquaflex 268 Water Resistant Polymer Cementitious Waterproof Slurry.
Removal is recommended when the existing tile, screed, plaster or coating layer has lost adhesion or shows signs of deep deterioration. Common symptoms include hollow tiles, cracked finishes, peeling coatings, water stains on the outer wall, water level loss, damp patches, algae growth around joints, or repeated leakage after previous repairs.
In these cases, the waterproofing problem may not be on the surface only. Water may already be moving behind the finish layer or through cracks and weak points in the substrate. Removing the damaged finish helps expose the original base, making it easier to clean, inspect, repair and waterproof the structure properly.
Swimming pools and water tanks are different from ordinary damp areas. The waterproofing layer is not only exposed to occasional water splashes; it must perform under long-term water immersion. That means the selected material should keep good water resistance, bonding performance and tensile strength after prolonged contact with water.
A polymer cementitious waterproof slurry is suitable for this type of concealed waterproofing system because it can be applied directly to mineral substrates and can work under tile or other protective finishes. For pool repair, the material should also be smooth to apply, easy to brush or roll, and able to form a continuous waterproof layer across the cleaned substrate.
This system is designed for pool and water tank repair after the damaged finish has been removed and the original concrete or masonry substrate is exposed.
| Product | Role in the system | Why it matters |
|---|---|---|
| CKS Primer | Substrate sealing and strengthening primer | Helps consolidate the cleaned base and improve the stability of the substrate before waterproofing. |
| Aquaflex 268 | Water resistant polymer cementitious waterproof slurry | Forms the main waterproofing layer for long-term water exposure areas such as pools and water tanks. |
· Long-lasting waterproofing performance: Aquaflex 268 provides stable water resistance and flexible performance, making it suitable for long-term water-retaining areas.
· High strength retention after immersion: The material maintains good tensile strength after soaking, helping the waterproofing layer remain stable under continuous water exposure.
· High bonding retention after immersion: Aquaflex 268 bonds firmly with the substrate and helps maintain adhesion performance after water immersion.
· Smooth application and good leveling: The slurry is easy to mix and apply by roller or brush, helping installers create a continuous, even waterproofing layer.
Use a scraper, chisel or impact drill to remove hollow tiles, cracked finishes, loose plaster, degraded coating layers and other weak materials. Continue until the original concrete or masonry substrate is exposed. Do not keep weak layers under the new waterproofing system.
Remove dust, laitance, loose particles, grease, algae and any surface contamination. The base should be clean, sound and stable before waterproofing. Cracks, honeycombs, corners, pipe penetrations and construction joints should be repaired or reinforced before the full-area coating is applied.
Apply CKS Primer evenly to the cleaned substrate for base strengthening and sealing. Allow it to stand for about 30 minutes until cured before applying Aquaflex 268.
Mix Aquaflex 268 at the recommended ratio: liquid : powder = 1 : 1.2. Add the liquid component first, then slowly add the powder while mixing. Continue mixing until the slurry is smooth, uniform and free of visible particles.
Apply the first coat evenly with a roller or brush. Make sure the coating fully covers the substrate and that corners, joints and edges are treated carefully. Allow the first coat to dry for about 4 to 8 hours, depending on site conditions.
After the first coat is dry, apply the second coat evenly. For better coverage, apply the second coat in a different direction from the first coat where practical. Avoid missing corners, edges and vertical-to-horizontal transitions.
After waterproofing is completed, allow the coating to cure for 48 hours. Only after the coating is fully dry should a water-retention test be carried out or the structure be filled with water for use.
· Swimming pool renovation after tile removal
· Water tank leakage repair
· Fish pond or landscape pond waterproofing
· Concrete water-retaining structures requiring a concealed waterproofing layer
· Areas where the waterproofing layer will be protected by tiles, screed or another finish after inspection
· Waterproofing directly over hollow, loose or weak finishes without removal.
· Skipping substrate cleaning, which may reduce adhesion between the coating and the base.
· Ignoring cracks, corners, pipe penetrations and construction joints before full-area coating.
·Changing the mixing ratio or adding extra water on site.
· Applying the second coat before the first coat has dried.
· Filling the pool or tank with water before the coating has fully cured.
Not always. If the finish is firmly bonded and the problem is minor, other repair methods may be considered after inspection. However, if the finish is hollow, cracked or deteriorated, removal is recommended so the new waterproofing layer can bond to a sound substrate.
CKS Primer helps seal and strengthen the substrate before waterproofing. This is especially important after demolition, because the exposed base may be dusty, porous or uneven.
Two coats help create a more continuous waterproofing layer and reduce the risk of missed spots, especially around corners, edges and uneven surfaces.
Allow the first coat to dry for about 4 to 8 hours before applying the second coat. Actual drying time may vary depending on temperature, humidity, ventilation and coating thickness.
After waterproofing is completed, allow 48 hours of curing. Carry out the water-retention test only after the coating is fully dry.
Aquaflex 268 is designed with good water resistance, bonding performance and tensile strength retention after immersion, making it suitable for water-retaining scenarios such as pools and water tanks when applied correctly.
