What is liquid waterproofing for concrete balcony?

Liquid-applied waterproofing can waterproof a balcony without removing existing tiles. Concrete and screed are suitable substrates.

The substrate must be clean, dry and sound. The drainage fall towards the outlet must be correct before liquid-applied waterproofing is applied: it follows the existing surface profile and cannot correct an inadequate fall. Because of their exposed position and connection to the building, balconies are particularly susceptible to moisture damage. Temperature-related building movement can cause cracks in concrete and damage at wall junctions, allowing water to enter through leaks. The elastic rubber membrane follows movement in the substrate and bridges cracks up to 0.5 mm within the waterproofing.

The waterproofing is taken seamlessly up the house wall. Railing fixings and the outlet are incorporated into the waterproofing, with a fabric insert providing additional stabilisation at these transitions. An edge restraint with a drip edge at the free edge directs water in a controlled manner. The liquid-applied waterproofing is applied in several coats; the required dry-film thickness and the detailing of junctions follow the application instructions for the relevant balcony construction.