After a sufficient concrete curing period, the structure should be filled to the spillway edge with water for at least 14 days in order to verify the tightness of the basin, highlighting and then plugging any leaks before installing the ceramic covering. Furthermore, it is equally important to anticipate which adjustments the structure is subject to once loaded. Any leaks or structural damage must be eliminated with localised interventions using epoxy resins.

Any imperfections concerning depressions or unevenness of the reinforced concrete structure must be corrected by levelling the thickness, using pre-mixed cemented mortars with aggregates of a suitable particle size. In any case, it is recommended to cast as accurately as possible in order to prevent thicknesses for levelling that are too considerable, especially in the case of walls. Before applying these mortars, it is necessary to perform thorough cleaning of the surfaces using a pressure washer or suitable mechanical equipment, in order to remove traces of release agents, dust, detached parts or anything else that may jeopardise adhesion. For levelling walls, Litokol offers the fibre-reinforced thixotropic cementitious structural plaster called LITOPLASTER T30. This is a pre-mixed cementitious mortar with the addition of special polymer in powder form that can provide excellent adhesion on the concrete support. The product is characterised by low shrinkage during hardening and can be used for thicknesses ranging from 4 to 30 mm. LITOPLASTER T30 can be applied both manually and using a plaster sprayer. Subsequent waterproofing can be carried out after about 7 days of curing. In order to smooth the bottom of the pool, it is advisable to create an adherent screed composed of LITOCEM quick-drying binder mixed with aggregates with a selected particle size of between 0 and 8 mm, respecting the dosage of 200 kg/m³. To make the screed adherent, an adhesive grout consisting of water, IDROKOL X20 and LITOCEM mixed in equal parts (1:1:1) must be applied directly onto the concrete bottom using a flat brush or broom and the LITOCEM-based screed cast wet on wet. Waterproofing can be carried out after 24-48 hours.

In order to waterproof the internal surfaces of the pool, the two-component elastic mortars ELASTOCEM and COVERFLEX can be used.
If ELASTOCEM is used, the product is applied to the surfaces in two layers using a smooth trowel making a total thickness of 2 mm, inserting anti-alkaline fibreglass mesh as reinforcement between the first and second layers. The seal of the angles between the walls and between walls and floor is ensured by interposing LITOBAND or LITOBAND MAXY sealing tapes between the first and second layers of mortar. These come in 10 or 50 linear metre rolls and have special pre-formed pieces for the internal and external angles (LITOBAND AI and LITOBAND AE). Near any outlets or spotlights, the special piece called LITOBAND P is inserted. The subsequent laying of the ceramic elements is possible after 4 days of curing. COVERFLEX is an alternative to ELASTOCEM mortar. This product is characterised by the fact that it can be applied by brush and roller as well as using a trowel, making it easier and quicker to use, especially in the case of structures with complex geometric shapes. Please note that in the case of laying a glass mosaic, it is not advisable to use a roller as ridges would form that would make it difficult to apply the adhesive with a 4 x 4 notched trowel. In order to use the products correctly, we recommend you read the relevant technical data sheets.

Laying and grouting ceramic elements and glass mosaics 

Generally, the internal coverings of swimming pools are made using ceramic tiles made from stoneware or clinker or using glass mosaics. For the bonding of these products, Litokol proposes the use of LITOKOL X11 and LITOPLUS K55 cementitious adhesives to be mixed with LATEXKOL elasticising latex which has first been diluted in water in a ratio of 1:1. Both products are defined as improved cementitious adhesives with no vertical slip and an extended open time, compliant with class C2TE according to the UNI EN 12004 standard. In particular, LITOKOL X11 is grey in colour and can be used to lay stoneware or clinker, while LITOPLUS K55, being characterised by an all-white colour and a fine particle size, is also particularly suitable for laying glass mosaics. The addition of the LATEXKOL latex gives the adhesive mortars a good level of deformability (S1 according to UNI EN 12002), which is essential in the case of ceramic surfaces subject to deformation such as in the case of swimming pools. If stoneware or clinker tiles are chosen, the adhesive should be applied using a trowel with appropriate toothing according to the format of the tile, and should also be spread on the back of the tiles (floating and buttering) so as to completely cover the back of them. In the case of glass mosaics, on the other hand, the trowel with 4 mm teeth must be used. Please note that in this type of application, the use of the mosaic on mesh is not recommended, as the adhesive normally used to glue the mesh to the glass tiles does not provide adequate resistance for prolonged contact with water. During this application phase, it is a good idea to check frequently that the adhesive has not formed a surface film (open time expired). It is therefore recommended to spread the adhesive on small areas, taking into account environmental conditions (high temperatures and windy conditions significantly shorten the open time).

In the case of ceramic tiles, laying must begin from the pool edge, taking note of the slopes, especially for the overflow edge. The joints dictated by the pool edge will be followed while laying the walls and then for laying the flooring. When laying pools with lanes, it is advisable to start from the centre line of the pool, then proceeding to the right and left side at the same rate, so that any cut tiles are divided equally. Under no circumstance lay the tiles side-by-side. Any structural joints must obviously be respected during laying.
When the adhesives are completely dry (about 24 hours after laying), it is possible to seal the joints. First of all, the joints must be cleaned thoroughly, removing all traces of adhesive residue. It is also advisable to remove the plastic spacers to prevent them from rising up through the grouted surface.

   
Sealing is performed using LITOCHROM 1-6 and LITOCHROM 3-15 cementitious grouts depending on the width of the joint and the desired colour. To obtain a lower absorption of the grout, improved elasticity and a higher adherence at the sides of the tiles, cementitious grouts can be mixed integrally with IDROSTUK latex in an aqueous dispersion, respecting the proportions shown on the packaging or the product datasheets. Once again, it is advisable to seal small areas in turn, as additivation with latex creates a sticky film on the surface of the ceramics. The surface must be cleaned with a damp sponge fairly quickly, taking care to remove all residual grout from the surface of the tiles. During the sealing operation, it is advisable to leave the joints destined for expansion joints, removing any impurities from them.


Instead of cementitious grouts, it may be beneficial to use the two-component epoxy mortars EPOXYSTUK X90 and LITOCHROM STARLIKE as alternatives, the latter available in 94 finishes. Using these materials brings many advantages. First of all, the greater mechanical and chemical resistance, which gives a much higher level of durability to the grout compared to cementitious grouts, even in the presence of sea or spa water or aggressive detergents used to clean the pool. The almost inexistent surface absorption of these products makes it possible to achieve compact grouting that does not allow the dirt to be absorbed. In addition, these products can also be used as adhesives, an advantage that cannot be ignored when laying glass mosaics, materials characterised by low thickness, avoiding raised adhesive in a different colour to that of the grout. In particular, LITOCHROM STARLIKE differs from traditional epoxy grouts due to its extreme ease of cleaning, which enables rapid grouting work. Today, thanks to a research project conducted in collaboration with the University of Modena and Reggio Emilia, and various microbiology laboratories, LITOKOL offers a new antibacterial epoxy mortar called STARLIKE DEFENDER. The product is able to eliminate 99.9% of the principal bacterial strains in both wet and dry environments according to the JIS Z 2801 and ISO 22196 standards, maintaining the unique characteristics of practical application and cleaning. The use of DEFENDER STARLIKE not only inside the pool but also in the external walkways or service areas of a swimming centre such as changing rooms, showers etc. makes it possible to obtain high levels of cleanliness, hygiene and safety. These requirements obviously gain more importance if STARLIKE DEFENDER is used as a grout for tiles which are also antibacterial.

The expansion joints in ceramic coverings must be made about every 3x3 linear metres, resulting in distributions of 9 m², making them coincide with a joint and meaning that tile cutting is unnecessary. The joints are also needed at all the angles between wall and wall and between floor and wall and in sudden changes of slope at the bottom of the pool. The joints must be sealed with the single component hybrid sealant in cartridge form LITOSIL PROOF. In order to apply the LITOSIL PROOF sealant, first clean the joints to be sealed, which must be perfectly dry, clean and free of dust or residues of adhesive or grout. Protect the edges of the joint using masking tape that is about 5 cm wide along the whole length of the joint and apply the sealant, extruding it from the cartridge using the nozzle, making sure to completely fill the joint. Then, using a steel trowel, level the surface of the joint and remove the masking tape when the sealant is still wet. Once the joints have been grouted and sealed, the tank can be filled after at least 7 days of curing.

                              

During periods of inactivity, the pool MUST NOT BE EMPTIED so as not to expose the structure to the direct effect of frost and earth pressure which, without the counterforce of the water, can lead to structural instability which, normally affecting the covering, can cause cracks, breaks and lifting up. In these periods, it is advisable to lower the water level by 10-15 cm, covering the entire surface with plastic sheeting, which must rest on the water surface to prevent ice formation. Suitable compressible materials made of pieces of polystyrene or special plastic pipes can be placed on the surface of the water.