How to repair cracks in swimming pools?

Summer is just around the corner. Sun, pool and friends is the perfect plan for these months of rest. But what do I do with my pool if it is leaking due to water leaks?

We explain how to repair cracks in swimming pools

Any type of pool, whether concrete, prefabricated, stainless steel, etc., requires proper maintenance to prevent leaks, filtrations and consequent water savings. However, we will focus on the concrete pools, where waterproofing and tuning the pool before the summer can save 500 litres of water per day – the approximate average consumption of a family of 4 – because if this is not done, there is a risk that the pool will be completely empty in a month due to possible leaks, according to Molins’ estimates.

The hidden dangers of cracks in swimming pools

The danger lies in both cases, in a continuous loss of water and its consequent expense, although the most dangerous thing is that this water tends to accelerate the degradation of the pool by ageing and oxidising its structure. Failure to remedy the problem can lead to a larger and more costly repair.

What causes cracks in the pool?

There are a number of factors that facilitate the appearance of cracks or fissures in swimming pools. One of the most common causes is earth movement. Other factors involved may be that the materials have aged and are beginning to crack or even water pressure which, over time, can cause cracks in the pool material. Similarly, weather conditions can also play a role in the deterioration of the pool shell.

What aspects must be taken care of when repairing a concrete swimming pool?

The clearest sign that the pool needs to be repaired is a drop in the water level, beyond that which can evaporate due to the high temperatures (usually around a finger a week). If the loss of water volume is more accelerated, it is a clear symptom of plumbing problems, leaks or defects in the waterproofing of the pool shell. Another unmistakable sign will also be alarming increases in the bill.

To keep everything under control, we recommend waterproofing the pool under tiles and sealing critical points such as impellers, spotlights and skimmers (the filters that suck in and retain waste) to ensure that they are watertight. This is a relatively short rehabilitation process, as depending on the size of the pool and the materials used, the execution times can vary between two weeks and a month, hence the importance of planning it in advance.

In addition, another aspect to pay attention to is the deterioration of the cementitious joints of swimming pools, which should be checked and repaired every 2 to 5 years.

According to Molins, a complete and successful renovation can make us forget about the pool for up to 10 years, as the durability of the waterproofing is directly associated with the quality of the materials and the execution and the type of final coating that is installed.

Types of cracks in the pool

Although there may be cracks in the regularisation mortars or in the tile joint due to ageing, the most important cracks usually affect the structure.

Concrete or concrete block swimming pools are rigid structures which, when subjected to pressure and counter-pressure forces from water or the ground, can suffer, more or less prematurely, a cracking problem due to settlement, load entry or expansion caused by the filling and emptying of the pool. When a crack appears, it is usually serious, normally of structural origin and its repair is urgent, in order to avoid water leaks… and because the infiltration of water into the crack and therefore into the structure accelerates its deterioration and ageing.

There are other types of cracks, which are those that occur between materials of different composition, skimmers, luminaires, etc… in contact with the concrete tank.

How to repair cracks in a concrete pool

In any case, to repair any type of crack, it is necessary to assess the type of crack and its magnitude. First of all, you will have to check the whole system: filter, pump, pipes… and switch on the water treatment plant to locate the exact area.

The pool must then be completely emptied to start removing all the paint or stoneware near the crack and to find out exactly how big the crack is.

It will be essential to start by cleaning the crack area approximately 10 cm on each side of the crack, open the crack by mechanical means and include – if the crack is larger than 1 mm – galvanised iron staples perpendicularly every 10 cm.

The crack will then be filled with PROPAM REPAR TECHNO quick-setting structural repair mortar. Subsequently, PROPAM IMPE FLEX flexible waterproofing can be applied in two coats with BETOFIBER GLASS embedded mesh in strips of approximately 15-20 cm, leaving the crack in between. You can also use the elastic band BETOTAPESEAL embedded with PROPAM IMPE FLEX itself, before finishing the rest of the pool, if it was made of gresite, placing the adhesive PAM ECOGEL FLEX and grouting with BORADA EPOLUXE. If the area is small, the tile can be bonded and grouted with BORADA EPOLUXE in the same step. In the case of cracks between materials, the solution is to seal the joint between the tile and the object, such as spotlights, skimmers, etc. with elastic materials such as BETOFLEX M20 polyurethane putty.