Waterproofing of swimming pools and fixing of ceramic tiles

RELATED MATERIALS

AQUAMAT-ELASTIC Two-component, highly flexible, waterproofing cement-based slurry

ISOMAT AK-ELASTIC High performance, two-component, elastic tile adhesive C2E S2

ISOMAT AK-22 High performance, extra flexible, polymer-modified adhesive C2 TE S1

ISOMAT AK-25 High performance, ultra flexible, polymer-modified adhesive C2 TE S2

MULTIFILL-EPOXY THIXO Two-component epoxy grout and tile adhesive

DUROCRET-PLUS Fiber-reinforced, polymer-modified, cementitious repair mortar

RAPICRET Rapid-setting, polymer-modified repair mortar

ADIPLAST Polymer latex for multiple improvements of mortars

PLASTIPROOF Plasticizing/water-reducing admixture for concrete

AQUAMAT-ADMIX Crystalline waterproofing admixture

FIBERGLASS MESH Fiberglass mesh for reinforcing waterproofing layers

 

NATURE OF THE PROBLEM – REQUIREMENTS

A usual way to prepare the final surface of a swimming pool is to overlay it with ceramic tiles since this way a long-lasting and aesthetically pleasant effect is produced.

Such a choice affects significantly the selection of the means for waterproofing the pool, since it sets specific requirements for the waterproofing to be carried out.

So, in this case, the waterproofing layer is applied prior to tiling and must have the following properties:

• It must provide effective waterproofing.
• It must be sufficiently flexible, particularly at the bottom of the pool, which is especially subjected to stress from expansions/contractions (mainly due to the influence of solar radiation), when the pool is empty.
• It must be long-lasting because its position between the pool’s structural elements and the layer of ceramic tiles makes future interventions difficult and expensive.
• It must bond strongly to the substrate and resist the probable negative pressure developed (for instance, when the pool is emptied and there is a periodic or permanent water table in the surrounding area).

The tile adhesive that will be chosen must show significant strength, high flexibility and resistance, since it will be continuously subjected to weather effects, to the pool’s water, and to the chemicals that this contains.

The tile grout that will be used must have significant resistance to the chemical stress evolved from the chemicals added to the pool water and from the strong tile cleaners.

SOLUTION

It is of primary importance for the supporting frame of the pool to have been correctly calculated, in order to effectively withstand hydrostatic pressure.

The requirements for waterproofing the pool can be successfully covered by the application of AQUAMAT-ELASTIC two-component, highly flexible, waterproofing cement-based slurry to the walls and bottom of the pool. The waterproofing layer created by using AQUAMAT-ELASTIC provides the following:

• Effective waterproofing.
• Strong bonding to the substrate and high resistance.
• High flexibility.
• Long-term duration.
• Resistance even to negative pressures, thus keeping the pool safe from both leaks and water ingress.

Moreover, during the concreting of the pool’s frame, the addition of PLASTIPROOF waterproofing admixture to the concrete at a ratio of 0.2-0.5% of cement weight is recommended. The addition of the crystalline AQUAMAT-ADMIX at a ratio of 0.8-1.0 kg per 100 kg of cement is also recommended.

Overlaying with ceramic tiles requires the formation of a smooth and stable substrate, on which they will be fixed. Thus, if necessary, the substrate is smoothed by the application of a strong cement mortar.

Tiles are fixed to the walls and bottom of the pool with one of the following tile adhesives; ISOMAT AK-ELASTIC, ISOMAT AK-25 or ISOMAT AK-22.

It is recommended that the pool tiles be grouted with MULTIFILL-EPOXY THIXO high strength and chemical resistant two-component epoxy tile grout. MULTIFILL-SMALTO 1-8 mm polymer-modified, water-repellent, cementitious tile grout can be used for grouting instead.

APPLICATION

I. Preparation of the substrate

1. Thorough cleaning of grease residues, deshuttering agents, dust, loose material, etc. from the surface.
2. Loose particles should be cleaned from existing cavities in the concrete.
3. Form wires and spacers should be cut to a depth of 3 cm.
4. Existing construction joints should be opened in a V-shape, towards the inside, along their entire length, to a depth of 3 cm.
5. 5. The above areas should be well dampened and filled with DUROCRET-PLUS polymer-modified cementitious repair mortar. Alternatively, when fast work is required, filling can be done with RAPICRET rapid-setting, polymer-modified, cementitious repair mortar. Consumption of DUROCRET-PLUS: 25 kg for filling a surface of 30-40 m² (indicative consumption for a usual concrete wall surface).

If the pool’s frame has an uneven substrate

In this case, the surface of the pool’s walls and bottom is smoothed by the application of a strong cement mortar. This process is carried out as described below:
Preparation of a strong cement mortar (cement : sand = 1:2.5) reinforced with ADIPLAST (5-10% of the cement weight), in order to smoothen the substrate along the surface of the swimming pool, at a thickness of 2-3 cm. Application of a bonding layer (spatterdash) reinforced with ADIPLAST polymer latex (cement : sand : ADIPLAST : water = 1:1:0.25:0.25) to walls of the swimming pool, in order to reinforce the cement mortar’s bonding, must take place. The bonding layer is applied as usual and after its hardening (at least 1 day) follows the application of the cement mortar. Application of a bonding layer reinforced with ADIPLAST polymer latex (cement : sand : ADIPLAST : water = 1:1:0.5:0.5) (fresh on fresh) to the bottom of the swimming pool, in order to reinforce the bonding of the cement mortar, must take place. The viscous mortar mix with the above mentioned ratio is applied to the properly prepared area with a brush, at a thickness of approximately 2 mm.

At least 21-28 days after the application of the cement mortar, time required for its hardening, AQUAMAT-ELASTIC can be applied.

If the pool’s frame has an even substrate

In this case, the application of a strong cement mortar is not required. AQUAMAT-ELASTIC waterproofing membrane is applied directly to the smooth substrate.

II. Waterproofing with the two-component, highly flexible waterproofing slurry AQUAMAT-ELASTIC

1. The content of the 25 kg bag (component A) of AQUAMAT-ELASTIC is added to the 10 kg of liquid (component B) under continuous stirring, until a uniform, viscous mixture is formed, suitable for brush application. A low speed mixer (300 rpm) should be used for mixing.
2. The walls and bottom of the pool should be brushed with 4 layers of AQUAMAT-ELASTIC. Each layer should be applied after the previous one has dried. In order to avoid cracking, each layer should not be more than 1 mm thick. Consumption: 4 kg/m² in total. At wall-to-wall and wall-to-bottom intersections, it is recommended to reinforce AQUAMAT-ELASTIC with fiberglass mess tape approximately 10 cm wide. The reinforcing strip should be placed immediately after the first layer of AQUAMAT-ELASTIC is applied and while is still fresh. After drying of this layer, two-three similar layers of AQUAMAT-ELASTIC should follow.

III. Fixing of ceramic tiles

Ceramic tiles should be fixed to the bottom and walls of the pool with one of the following tile adhesives; ISOMAT AK-ELASTIC, ISOMAT AK-22 or ISOMAT AK-25.

IV. Tile grouting

It is recommended that the pool wall and floor tiles be grouted with MULTIFILL-EPOXY THIXO epoxy tile grout. Alternatively, MULTIFILL SMALTO 1-8 mm cementitious tile grout can be used for grouting.

REMARKS

• If plastic spacers have been used, FLEX MS-45 sealant should be used to seal the inside of the spacers, to a depth of 3-4 cm, and at a later stage DUROCRET-PLUS should be used to fill the gap around them, to a depth of 2-3 cm.
• Temperature during application of all materials should be between +5oC and +35oC.
• The fresh AQUAMAT-ELASTIC layer must be protected from high temperatures, rain and frost.
• Due to cement content, the product reacts with water forming alkaline solutions, thus is classified as irritant.
• Filling of swimming pool with water can take place after 7 days from the application of MULTIFILL-EPOXY THIXO.
• The minimum hardening temperature of MULTIFILL-EPOXY THIXO is +10oC.
• Please consult the safety instructions written on the packaging before use.
• For further directions on the application of the above mentioned materials, please refer to the attached Technical Datasheets.