Why have cracks appeared in grout joints?
Possible reasons: – Deflection in the substrate – Moisture expansion in underlying boards that are not water resistant – Tiles not adequately bonded to substrate – Grout joints wider than max. recommended width for grout product concerned – resulting in drying shrinkage – Joints not fully filled, leaving voids underneath grout – so grout not supported. To increase flexural and (at tile edges) adhesion strength, and reduce water permeability, use BAL Admix GT1 or use a BAL epoxy resin-based grout.
