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Waterproofing of swimming pools with polyurethane elastomer

Origin of moisture in swimming pools

When waterproofing is not completely watertight anymore, then dampness appears in the pools, which can have two different origins.

a) Filterings from the outside, they are detected because the pool water gets dirty because of the particles that are dragged by the ground taken by the pool. When the water from the outside seeps into the pool, it causes the pool liner to detatch.

b) Leaks from the inside, more difficult to detect if they are small and go towards the ground, they occur when the pool ceases to be watertight, and they can happen towards the inside, in the pump enclosure or towards the outside, to the ground .

Waterproofing of swimming pool polyurethane elastomer

Waterproofing of swimming pools

There are many systems to make pools be waterproof, and these can be grouped into liquid systems and laminate systems.

Liquid systems for the waterproofing of swimming pools

These waterproofing systems are applied on the pools in a liquid state, achieving thus a total adhesion on 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.

polyurethane elastomer

We should also take into account the conditions for its application. In order to guarantee the quality of the liquid membranes, we will have to evaluate humidity in the environment, temperature, the quality and humidity of the support, etc.

Polyurethane elastomer URESPRAY P-500 Factsheet


Urespray P-500 is a pure polyurea based elastomeric system obtained by the reaction of two quickdrying liquid components applied by mechanical projection (spraying).

Description of the components

  • Component A: Urespray P-500. Mixture of Polieteramines
  • Component B: Isocianato 5332. Modified MDI (Diphenil methane diisocyanate)


The main applications of Urespray P-500 are in the industrial and building fields, mostly for
waterproofing and protection of roofing, balconies, overhangs, parking areas, concrete structures, water deposits, etc …., as well as elastomeric coating for polyurethane foam and expanded polystyrene.

Due to the spray application it provides a uniform coating areas where the surface is irregular or in areas with complicated geometry, (forming a uniform film).


The product is designed for application with standard two component spray equipment having component pressure from 150 to 200 Bars, which generally allows dosing in a ratio of 1:1, components being heated at 70-80 ºC.

Processing conditions

Surfaces to be sprayed should be clean, dry and free from dust and grease. Temperature should range
from -10 and 70 ºC, with relative humidity being below 75%.

The surface needs to be prepared by means of sand blasting, especially when applied to extremely smooth surface be applied.

The properties of Urespray P-500 allow it to adhere to any surface. However, adherence should be tested, using primers for some difficult substrates. For correct operation, a very thin first layer is recommended. The second pass (also thin) may be made as soon as the first one is dry, by using a criss-cross pattern. For effective waterproofing, the surface should be free of condensed moisture because it may cause pores and bubbles, so a very thin first layer will help to detect moisture presence in the substrate, in which case blisters and bubbles will appear. If it occurs, the first layer will need to be removed then reapplied when the surface is completely dry.

Urespray P-500 can be pigmented in several colors, by means of the addition ‘in situ’ of the corresponding Urespray Paste in component A. Component A tends to settle due to the passing of time.

Therefore, be sure to stir it until fully homogenized, especially if some pigment has been added.

For further specifications such as the characteristics of components, specifications or characteristics of the foam systems, download the factsheet.

Storage recommendations

All Components are hygroscopic, and should be stored in drums or hermetic deposits. Storage
temperature should be between +15ºC and +25ºC.

Lower temperatures that could cause crystallization in the isocyanate should be avoided, as well as higher temperatures that may provoke alterations in Component A.

With correct storage, component A (Urespray P-500) has a shelf life of 12 months and for component B (Isocianato 5332) 9 months from production date.

Safety recommendations

With the right handling, the system has no great risks. Avoid contact with skin and eyes. If contact occurs, wash well with lots of water. During system production and handling, the Safety Data Sheets should be observed. More extensive information of the subject can be found in the Safety Data Sheet for each product.


Information about product supply can be obtained by contacting our Sales Department.

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