The popular approach to controlling efflorescence on tiled balconies, is to provide a secondary membrane directly beneath the tiles. Another approach is to bond the tile bed directly to the substrate and install a single membrane on top.
Both of these methods are popular and can be effective in controlling efflorescence from the tile bed, but there are pit-falls. Firstly, efflorescence is also known to release from tile adhesive and grout, which are both located above the membrane. Secondly, these methods trap all the moisture in the tile bed under an impervious membrane. Moisture in the tile bed concrete mix can take weeks to evaporate meaning weeks of good weather is needed. Otherwise, if the moisture content is still too high when a membrane is applied, it can cause major problems.
A trap to watch out for!
A large Sydney-based building company recently had to address major defects caused by a secondary membrane. The secondary membrane terminated beneath aluminium sliding doors leading onto balconies on a large multi storey building. The moisture in the tile beds was trapped between the primary membrane and the secondary membrane, but found an exit point beneath these aluminium doors. As moisture from the tile bed evaporated under the doors it brought with it all the dissolved salts in the concrete. The result was major corrosion of the aluminium doors caused by the salts, and the doors had to be replaced.
Efflock is permeable and hydrophobic. Permeability allows moisture during the construction phase to evaporate from the tile bed. The hydrophobic effect prevents efflorescence. Normal construction practices can be used without complex and labour-intensive secondary membranes. With Efflock, the tiler can even wet lay his tiles! By completing with Efflock in the grout, you have a bullet proof system.