Find out all you need to know about specifying the correct products for tiling in swimming pools to avoid installation failure.
The design of swimming pools varies greatly depending on the intended use: from competition pools which must be rectangular, built to strict tolerances and 25m or 50m long, through hydrotherapy pools to health clubs, leisure centres, spas and private pools where the form is only limited by the imagination and the budget. However all of these have to take the same criteria into consideration, namely safety, longevity of the finishes and technical and aesthetic performance.
Kerakoll’s advanced swimming pool system ensures the longevity of the tiling installation as it is not affected by aggressive water conditions, and also has very low VOC emissions so helping to improve indoor air quality, so protecting the installation team’s health.
Pool Tanks
Several materials are used in swimming pool construction although concrete is the most widespread with steel being used more rarely. This article considers tiling to concrete pools which are built either from site cast concrete using shuttering, sprayed concrete, reinforced blockwork or cavity wall construction with reinforced concrete. When using blocks, the rendering becomes part of the watertight construction. Structural movement joints within the pool shell should be avoided if possible.
Rendering/Levelling
Where the surface is not sufficiently smooth or level to allow tiling to take place, Keralevel Eco LR is used to prepare it for tiling. This can be instead of, or in addition to a screed, and allows you to smooth and level the walls and floors of pool tanks for thicknesses between 1 & 25mm. It has a long working time so it can be used for large surface areas and is ready for tiling after a couple of hours.
The final surface specification should be 3mm under a 1.8m straightedge. If the render is being applied over blockwork, the tolerances should be built into the specification for the blockwork, as this is more accurate than is generally required in traditional construction.
The floors and walls in the rest of the pool facility should be prepared to the tiling specification: that is 3mm under a 2m straightedge. Areas subject to water splash should be laid to falls to allow adequate drainage of any water that has accumulated. Keralevel Eco LR’s thixotropic consistency makes it the perfect product for achieving this.
Waterproofing
Once the pool sides and floor have been prepared, the tank should be waterproofed before tiling. This is done with Aquastop Nanoflex, a flexible waterproofing membrane which is created chlorine resistant and anti-alkali, and is created with nanotechnology. The use of Aquastop AR1, a special reinforcing mesh, within the first layer of Aquastop Nanoflex is advised to fully reinforce the membrane. Aquastop 120 waterproofing tape is then applied to all joints, bedded into the waterproofing membrane. Once complete a second layer of Aquastop Nanoflex is applied to complete the system.
Aquastop Nanoflex should also be applied to all areas that will be in direct contact with water including the area around the pool, foot baths, changing rooms etc. and should continue up to the walls of the room in which the pool is situated.
Sealing the Hydraulic & Electrical Systems
All hydraulic and electrical parts that come into contact with water should be waterproofed with Nanosil Eco, a neutral, non-corrosive silane sealant with a reduced solvent content that comes ready to use.
Tiles
Tiles should have a water absorption of 3% or less and be of extruded or dust pressed manufacture. They should have adequate slip resistance in wet areas and particularly on steps and ramps. Tiles for pools used for scuba diving and canoeing should have a higher modulus of rupture due to the higher risk of damage. A tiling specialist can advise on the suitability of particular tiles.
Adhesives & Grouts
The most important criterion when choosing adhesives and grouts, especially for the pool tank, is resistance to chemicals in the pool water. This is influenced by various factors including the quality of the mains water and the chemicals that are used to treat it. Pools with low levels of bicarbonate alkalinity and low calcium content can be aggressive to cementitious mortars and grouts, as can water that is too acidic or alkali.
Kerakoll’s Biogel range of adhesives are perfect for use when tiling both pool tanks and the surrounding area. Biogel No Limits is the standard set version which is suitable for all substrates and uses. It is ready for grouting after 16 hours in normal conditions, and the pool can be used after approximately 14 days. Where time is tighter, Biogel Revolution is the rapid set version, this will allow grouting after 3 hours and swimming pool use after around 7 days. The Biogel range has a very low CFP and VOC emissions, with a reduced frost risk, and high deformation. It is also very popular with tilers as it is easy and pleasant to tile with.
Once the adhesive has set, the installation should be grouted with Fugalite Bio. This is a water-based resin grout that has been proven to be hypoallergenic in testing, and certified by the CSTB Institute to prevent the proliferation of mould and bacteria. It is non-toxic and non-hazardous with a reduced solvent content and very low VOC emissions. It has been developed as a non-absorbent waterproof grout that is resistant to UV light, and fully tested by CATAS for colour durability in external conditions.
The final step is to seal any expansion joints with Silicone Color, a decorative sealant for tiles which is available in 50 different colours. It is ideal for swimming pools and other areas in permanent contact with water, and has low VOC emissions and a solvent content of ≤ 5g/kg. It has a curing time of around 20 minutes, so will not hold up the commissioning of the pool.
Technical and specification support
Tilemaster Adhesives team is more than happy to get involved in the specification process to ensure that the right products are chosen to enable the project to run smoothly without any problems once complete. Please do contact them for further advice and support.