Typically, many swimming pools are constructed of concrete, which does not have any inherent waterproofing properties. In fact, concrete is rather proud and allows permeation of water over time unless it is treated with a layer of waterproofing coating applied to the pool shell. To be a fully functional pool without leakages, the swimming pool has to be completely treated with waterproofing to prevent any seepage through cracks and pores. However, most leakages occurs in areas where it is more challenging for waterproofing to be applied – in areas such as drainages, lighting and pipings, water might still seep in if waterproofing is not properly applied around the edges.
Effective
Here are some of the appropriate materials that have been proven to be effective in waterproofing swimming pools:
Polyurethane – a crystalline compound which forms a water-resistant membrane with greater durability than bitumen-based materials
Polyvinyl chloride (PVC) and thermoplastic polyolefin – waterproof sheets that create a durable, strong membrane
Ethylene propylene diene monomer rubber (EPDM) – a synthetic rubber with extremely durable qualities. They are proficient waterproofing sheets that is highly efficient for swimming pool waterproofing.
CEMENTITIOUS waterproofing method
The benefits of cementitious coatings
The waterproofing you choose needs to match the requirements of your project. No one coating will work for every situation, and the wrong one can lead to costly repairs and reworks. Cementitious waterproofing has the benefit of a wide range of suitabilities and strengths, including:
- Monolithic – Cementitious waterproofing provides a seamless coating system
- Abrasion resistant and weather resistant – Important where wear or exposure is an issue
- Chemical resistant – Can be used where chemical spills or storage is necessary
- Excellent bonding capability – Bonds to porous and non-porous surfaces
- Works with both negative and positive side pressure
- Resists carbon dioxide and chloride ion diffusion – Prevents concrete cancer and spalling
The two types of cementitious coating: Crystalline and flexible
- CRYSTALLINE CEMENTITIOUS WATERPROOFING
Crystalline coating is composed of cement, specially treated quarts (or silica), and proprietary chemicals. When combined with water, it undergoes a reaction and forms a crystalline structure that permeates and fills pores, micro cracks, and capillaries in concrete. This effectively blocks off those channels that would otherwise allow the ingress of water and damaging chemicals. Crystalline coatings are resistant to hydrostatic pressure and chemicals, and can be used for both positive and negative sides of water-retaining concrete structures.
Application: Crystalline coating works like a surface treatment, diffusing through the surface of the concrete and bonding with it. It can also be included in the wet concrete before pouring, providing waterproofing in its own matrix, or sprinkled onto the wet slab. - FLEXIBLE CEMENTITIOUS WATERPROOFING
Also called polymer-modified cementitious waterproofing, this is a breathable, flexible, and versatile option that is can be used for a wide range of applications including foundation walls, water storage tanks, basements, secondary containment bunds, swimming pools, digesters, pumping stations, sewers, and the protection of marine structures. This versatility is down to the ability to include the powder cement admixture in a range of polymer coatings.Flexible cementitious coatings provide waterproofing for positive and negative side installations, can be used for crack bridging, and are breathable.
Application: Flexible cementitious coatings are two component – mix the powder component with the liquid binder component then, when properly combined, apply it by airless spray, brush, trowel, or skid leveller. Can be reinforced.
Liquid systems for the waterproofing of swimming pools
These waterproofing systems are applied on the pools in a liquid state, thus achieving a total adhesion to the support. Some types, such as polyurethane elastomers, have a certain degree of elasticity, being able to absorb movements and fissures without breaking. Polyurethane elastomers can be adapted to any surface and design, solving singular points.
The main advantage of polyurethane elastomer is that it creates a continuous membrane, without joints, and adhered to the support. The fact of creating continuous waterproofing without joints or welds and completely adhering to the support reduces the chances of leakage. This feature implies the ability to locate leaks because, as it is adhered to the support, water can not circulate under the waterproofing.
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Another high risk area is where penetrations are part of the structure, so careful product selection of waterproofing products and detailing is imperative. Penetrations can vary, from sleeved services to non sleeved, things like suitible puddle flanges and or hydrophilic strips and waterproof mortars, waterproof mastics, or combinations of such need consideration.
The usual material used in swimming pool construction is reinforced concrete with the added benefit of internal or negative side waterproofing. Consideration to both ingress and egress of water needs to be factored equally when designing an appropriate waterproofing system.
A Waterproofing Designer should consider many factors, such as the grades and dimensions of the concrete structure, is it earth retained on all elevations, what are the intended finished surfaces to be applied over the waterproofing and is it to be exposed to direct UV radiation during its service life.
Another major concern, especially with thinner concrete elevations or sections; is flexing of the pool shell when both filled and emptied. Frequent filling and emptying maybe required for maintenance, cleaning, replacement of failed tiles, etc. These flexing/tensile bending events can lead to failure of post applied liquid or render types of waterproofers, with best advice always being to empty and re-fill pools over several days rather than at once to reduce the chances of “shocking” concrete structures and therefore promoting cracking of the substrate itself.