How to waterproof a concrete pool?

Antonio Neves
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Antonio Neves
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How to waterproof a concrete pool?

To build swimming pools, the most common and used form in civil construction is the classic masonry. However, it is possible to build a pool from reinforced concrete. Today, we will bring in this article important information about concrete pools and, mainly, how their waterproofing should be done.

The waterproofing process is one of the main steps when we talk about concrete pools construction. This is because pools are wet areas, that is, they have direct contact with water, exerting positive pressure on all their sides.

A lack or failure of waterproofing of concrete pools can generate several inconveniences and losses in addition to the much higher cost to repair when compared to the preventive cost of waterproofing.

Therefore, waterproofing both the inside and outside of pools is totally indispensable to avoid the loss of water from the pool to the surrounding land, besides prolonging the useful life of the structure.

Thinking about the importance of waterproofing in swimming pools, we prepared this article to help you learn more about concrete pools, which are also widely used. So, keep reading to understand everything about them and how to do the waterproofing the right way and not have problems and expenses in the future. Let's go?

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Why waterproof concrete pools?

If you already work in civil construction, you must know that waterproofing swimming pools is fundamental. Even so, we will highlight some important points to convince you, once and for all, that the waterproofing of these areas cannot be overlooked at all.

And there's no point in using a good product if you don't do the procedure in the recommended way, right? So, read this article until the end so that you don't make a mistake!

First of all, concrete pools should be waterproofed both on the outside to preserve the structure, avoiding contact with the surrounding ground humidity and on the inside to prevent water loss from the pool to the surrounding ground. See that it is not so simple.

A waterproofing failure at any of these points could cause major inconvenience.

But what kind of problems can arise? If the waterproofing is not done in the correct manner, problems may occur such as loose lining, the appearance of stains, contamination of the pool, water leakage around the pool (even more so when it is connected to the structure of other places, such as garages and rooms) and serious structural problems as the water infiltrates the structure and may even compromise the pool itself.

The problems, many times, are not simple and cheap to solve. For this reason, I am insisting that a good and efficient waterproofing of your concrete pool is essential.

What are the differences between reinforced concrete and masonry pools?

Both concrete pools and masonry pools need to be waterproofed, because in both cases the structure is subject to the action of water, whether from the pool water itself or from the humidity of the surrounding ground. So, you will not escape this. But, we will explain everything so that there is no doubt about how to do the correct procedure.

Basically, the difference between reinforced concrete pools and masonry pools is only in relation to the way they are built. Reinforced concrete pools, unlike masonry pools, have an iron mesh in all their surfaces, both in the bottom and sides, which guarantees an extremely resistant pool. If built and waterproofed in the correct way, it is a pool that lasts for many years without presenting a single problem.  

Masonry pools can be either ceramic or concrete and are built in the classic way you already know. They are the most used ways to build pools nowadays.

What are the main features of reinforced concrete swimming pools?

We will now learn about the characteristics, including advantages and disadvantages of using reinforced concrete pools. Basically, its characteristics which differ from other types of pools are as follows:

  • Construction method: masonry pools are built from beams and columns while reinforced concrete pools have a concrete and iron structure, presenting a one-piece shape;
  • Cost: concrete pools have a higher cost than other types of pools, but also have other advantages;
  • Design freedom: reinforced concrete gives freedom to build a swimming pool of any shape, size and depth.
  • Resistance: it is a very resistant structure which, if correctly executed, gives very little maintenance, lasting for many years.

Concrete pools have interesting advantages. Therefore, it is important to evaluate to understand if it is the ideal way of construction for your pool. Remember that there are other types of pools that also have characteristics that may be favourable to you, but it is up to you to analyse which one best meets your needs.

What is the best product to waterproof concrete pools?

Cutting to the chase, the best product for waterproofing concrete pools is Blok ST, a flexible waterproofing resin that acts in areas with positive hydrostatic pressures. Ideal for sealing leaks and fighting humidity, Blok ST is perfect for waterproofing swimming pools. Among its characteristics, we can mention: excellent impermeability, flexibility and adherence to cement substrates; it does not alter the potability of the water and is resistant to high positive hydrostatic pressures, as is the case with swimming pools. 

Pools are structures that are subject to movement over time and therefore flexible waterproofing products should be used. Also, you need a product that is suitable to combat positive hydrostatic pressures from water. Blok ST meets these conditions, so it is the perfect waterproofing product to protect swimming pools.

How to waterproof concrete pools?

When we think about waterproofing swimming pools, it is normal for people to think of protecting only the inside of the pool, preventing the water from leaking into the surrounding area. However, as we have already mentioned, it is essential to also waterproof the outside of the pools to prevent the structure from being affected by the humidity that comes from the ground.

Therefore, for a complete waterproofing, it should be done both on the inside of the pool and on the outside. Then you will have a pool protected against humidity coming from all sides. Waterproofing only one of these surfaces is not enough and, for sure, at some point you will have to deal with infiltrations.

But, if you've got this far, I'm sure you're willing to do your complete pool waterproofing the right way, right? Let's explain.

First of all, waterproofing should be done when the work is being carried out, before the pool is finished. It is also essential to hire a specialized team to carry out the service.

Basically, the waterproofing process is divided into preparing the surface in accordance with NBR 7200, preparing the product, applying the waterproofing material, waiting for drying between coats and curing time. Always using PPE, equipment for applications and all recommendations of the manufacturer, according to the product datasheet.


You can understand the importance of doing a good and complete waterproofing of concrete pools, right? Today, our goal was to bring you all the necessary information so that you do not run the risk of failing in the waterproofing of concrete pools, because a small mistake can cause huge inconvenience. Remember, therefore, to use Blok ST to ensure excellent waterproofing in your pools. Talk to the Blok team to learn more about this product and many others that can also be solutions for your works!

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