Waterproofing Ponds - Including Fish Ponds and Water Features
The use of Vandex cementitious waterproofing products is often associated with civil engineering applications such as reservoir waterproofing. However they can also provide a cost-effective waterproofing solution for ponds and water-features.
The diagram below shows how Vandex Unimortar 1 and Vandex BB75 can be used to waterproof a typical concrete pond or water feature:
First a fillet is formed around the inside-perimeter of the pond using Vandex Unimortar 1. Once the Unimortar 1 has cured, two coats of Vandex BB75 are applied to the sides and floor of the pond.
If a tiled finish is required, a 3:1 sand:cement render should be applied over the second coat of Vandex BB75 whilst it is still green. This will provide a suitable base for tiles to be fixed using a suitable waterproof tile grout.
Vandex BB75 and Unimortar 1 are both approved for use in contact with drinking water. Nevertheless, where fish are to be kept in the pond, it is important to take precautions to ensure that the water quality is suitable for the species of fish to be kept. To this end, advice should be sought from the fish supplier.
In common with all cementitious coatings, Vandex BB75 and Unimortar 1 will cause the water in the pond to have a high pH (typically between 12 and 13) when first filled. To bring the pH down to a more neutral level, the pond will have to be emptied and filled several times until the correct pH is reached.
Preferably, pipe inlets will be formed insitu during the casting of the concrete and sealed using Vandex Expaseal B Plus expanding waterstop, as shown on the lefthand diagram.
Where it is necessary to install pipes after the casting of the concrete, these can be sealed using Vandex Uniflex.
Other Types of Pond Construction
Vandex products can also be used to waterproof ponds constructed from brick or concrete blocks. Please contact our technical department for details.
Details of other types of water-retaining structures that can be waterproofed using Vandex products can be found on our water-retaining structures page.