Waterproofing of swimming pools and painting with epoxy coating
RELATED MATERIALS
AQUAMAT-ELASTIC Two-component, highly flexible, waterproofing cement-based slurry
EPOXYCOAT-S Two-component epoxy coating suitable for swimming pools
EPOXYPRIMER 500 Two-component, water-based epoxy primer
ADIPLAST Polymer latex for mortar improvement
AQUAMAT-ADMIX Crystalline waterproofing admixture
PLASTIPROOF Plasticizing/water-reducing admixture for concrete
DUROCRET-PLUS Fiber-reinforced, polymer-modified, cementitious repair mortar
SM-27 Special solvent for epoxy coatings
NATURE OF THE PROBLEM – REQUIREMENTS
A common and affordable way to prepare the final surface of a swimming pool is to paint it with a special paint, such as an epoxy coating. This is a technically effective solution that is clearly more affordable than overlaying with ceramic tiles.
Choosing an epoxy coating significantly affects 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 applied under the epoxy paint must deliver the following:
- Effective waterproofing.
- Sufficient elasticity, particularly at the bottom of the pool, which is subjected to expansion and contraction stresses mainly due to the influence of solar radiation, when the pool is empty.
- Strong adhesion to the substrate and resistance to 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 epoxy coating to be used must have the following properties:
- Elasticity to withstand cracking caused by possible expansion and contraction stresses.
- Resistance to water and chemicals used to treat the pool water (e.g. chlorine).
- Resistance to weather conditions (e.g. solar radiation, frost, etc.).
SOLUTION
Properly calculating the pool frame is of primary importance to ensure that it can successfully withstand hydrostatic pressure.
The requirements for waterproofing the pool can be successfully met by the application of AQUAMAT-ELASTIC highly flexible, 2-component, brushable waterproofing slurry to the walls and bottom of the pool. The waterproofing layer created by using AQUAMAT-ELASTIC provides the following:
- Effective waterproofing.
- Strong adhesion to the substrate and high resistance.
- High elasticity.
- Long-lasting durability.
- Resistance even to negative pressures, thus keeping the pool safe from both leaks and water ingress.
Moreover, during the concreting of the pool frame, it is recommended that PLASTIPROOF waterproofing admixture be added to the concrete in the ratio 0.2-0.5% of the cement weight and AQUAMAT-ADMIX crystalline waterproofing admixture at a consumption 0.8-1.0 kg per 100 kg of cement.
The requirements for elasticity and resistance to chemicals that the coating must satisfy are successfully met by the application of EPOXYCOAT-S epoxy coating. This 2-component epoxy system shows increased elasticity and resistance to friction. Furthermore, it is highly resistant to a variety of chemicals, such as diluted acids, alkalis, petroleum products, some solvents, water, seawater, and to weathering.
APPLICATION
Substrate preparation
In case the pool frame has a smooth substrate
- Thorough cleaning of grease residues, formwork release agents, dust, loose materials, etc. from the surface.
- Loose particles should be cleaned from existing cavities in the concrete.
- Starter bars and spacers should be cut to a depth of 3 cm.
- Existing construction joints should be opened in a V-shape, towards the inside, along their entire length, to a depth of 3 cm.
- The above areas should be dampened well and filled in with DUROCRET-PLUS fiber-reinforced, polymer-modified cementitious repair mortar. Alternatively, when fast work is required, RAPICRET rapid-setting cementitious repair mortar. Consumption of DUROCRET-PLUS: 25 kg for filling a surface of 30-40 m2(typical consumption for a usual concrete wall surface).
- The entire surface of the substrate should be dampened well, but without creating any water puddles.
In case the pool 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. The following workflow is carried out:
- Thorough cleaning of grease residues, formwork release agents, dust, loose materials, etc. from the surface.
- Cutting of starter bars and spacers from the wall’s surface.
- Preparation of a strong cement mortar (cement : sand = 1 : 2.5) with the addition of ADIPLAST (1 kg per 25 kg of cement), in order to smooth the substrate along the pool’s surface, 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 the pool’s walls, in order to reinforce the cement mortar’s bonding to them, must take place.
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 pool, in order to reinforce the bonding of the cement mortar to it, must take place. - At the intersection of the walls and bottom of the pool and where walls meet, it is recommended that a fillet be formed during the application of the cement mortar to facilitate the subsequent application of the epoxy products.
- The surface is well dampened but without creating water puddles.
Waterproofing with AQUAMAT-ELASTIC
- At least 14 days after the application of the cement mortar, time required for its hardening, AQUAMAT-ELASTIC can be applied. 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) may be used for mixing.
- The pool’s walls and bottom should be covered with 3-4 layers of AQUAMAT-ELASTIC. The final layer of AQUAMAT-ELASTIC must be pressed with a smooth trowel while is still fresh in order to achieve a smooth finish. 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: 3-4 kg/m2in total. Along intersections between the walls and the bottom of the pool, it is recommended to reinforce AQUAMAT-ELASTIC with a polyester tape or a 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, 2-3 similar layers of AQUAMAT-ELASTIC should follow.
Priming and painting with EPOXYCOAT-S epoxy coating
- At least 3-4 days after the application of AQUAMAT-ELASTIC and as long as it is dry (moisture < 4%), the surface of the pool’s bottom and walls should be primed with EPOXYPRIMER 500. Components A (resin) and B (hardener) are packaged in two separate containers, having the correct predetermined mixing ratio by weight. The entire contents of component B is added to component A. Mixing of the 2 components should take place for about 5 minutes, using a low-speed mixer (300 rpm). EPOXYPRIMER 500 can be thinned up to 30% with water. It is important to stir thoroughly the mixture near the sides and bottom of the container to achieve uniform dispersion of the hardener. Consumption of EPOXYPRIMER 500: approx. 200 g/m2.
- After the primer has dried, and within 24-48 hours of its application, the pool should be painted with EPOXYCOAT-S epoxy coating. Components A (resin) and B (hardener) are packaged in two separate containers, having the correct predetermined mixing ratio by weight. The entire contents of component B is added to component A. Mixing of the 2 components should take place for about 5 minutes, using a low-speed mixer (300 rpm). It is important to stir thoroughly the mixture near the sides and bottom of the container to achieve uniform dispersion of the hardener. EPOXYCOAT-S may be applied as is or thinned up to 5% by weight with SM-27 special thinner, by brush, roller or airless gun in 2 layers. The second layer should be applied after the first one has dried but within 24 hours of its application. Consumption of EPOXYCOAT-S: 200-300 g/m2per layer.
REMARKS
- Special attention must be paid to the proper placement of swimming pool fittings, namely drains, skimmers, water valves, lights, etc., which are vulnerable points as far as waterproofing is concerned. DOMOSIL-POOL silicone sealant is suitable for sealing such types of joints.
- EPOXYCOAT-S contains solvents. For application in enclosed rooms, ensure good ventilation.
- Working time of epoxy systems decreases when ambient temperature rises.
- Bonding between successive layers may be severely affected by the intervention moisture or dirt.
- Epoxy layers should be protected from moisture for 4-6 hours after application. Moisture may whiten the surface or/and make it sticky. It may also disturb hardening. Faded or sticky layers in parts of the surface should be removed by grinding or milling and laid again.
- In case recoat time is longer than expected or in case old floors are to be laid again, the surface should be thoroughly cleaned and ground before application of the new layer.
- Before application, consult the directions for safe use and precautions written on the packaging.