Waterproofing of swimming pools, ponds, tanks, etc

Waterproofing of swimming pools, ponds, tanks, etc

Given the function carried out by swimming pools, ponds, water tanks, ornamental fountains, etc., and for which they are destined, they require complete watertightness from the moment of execution and, therefore, they must be free from leaks.

Preliminary analysis

All the factors that may cause possible water leaks must be taken into account:

  • That the nature of the materials used do not guarantee their watertightness (e.g.: absorbent or very porous materials).
  • Use of materials with little resistance to pressure or counterpressure, causing filtration points therein.
  • Construction materials which are affected by climate changes, which can produce fissures and cracks that consequently affect their watertightness.


Based on the foregoing and in order to ensure full watertightness, we must use products that:

  • Support the pressure and counterpressure of the water.
  • Are resistant to the possible aggressiveness of salts dissolved in water.
  • Are highly resistant to climate changes.

Technical considerations

Firstly, we must follow the steps below to prepare the substrate to be waterproofed:

  • If there are evident water filtration points or leaks, these must be opened forming straight edges and subsequently sealed with GECOL Pronto.
  • If there are cavities and voids in the concrete substrate, they must be filled with a repair mortar of the GECOL Reparatec range (depending on the thickness and resistance of the system).
  • The substrate must always be clean, without traces of dust, oils or release agents.
  • Correctly treat special points (angles, corners, fissures, etc.).
  • If tank capacity is less than 8,000 litres, it must be filled and emptied at least once prior to commissioning.


In accordance with the type of substrate to be waterproofed, we have different technical mortars:

  • Smooth concrete:

Two factors must be taken into consideration:

  • Water penetration routes (positive or negative pressure).
  • Possibility of movement of the substrate.

If prior regularization of the substrate is required, it shall be executed using a repair mortar of the GECOL Reparatec game.

  • Brick or concrete block:

GECOL Imper-G (applying a minimum thickness of 10 mm in all points to ensure complete waterproofness).

Recommended products



Fast setting

Thin layer from 2 to 5 mm

Thick layer 10 mm


Fast setting

Concrete repaires



Structural- fast setting

Warnings: The data provided by this Constructive Solution were prepared based on standard onsite installation processes. However, we recommend that you consult our Technical Department in the event of any specific circumstance info@gecol.com