Black Museum part 1
Author Steve Kirby

(click on thumbnails for larger image)

The compressed sheet has cracked damaging the membrane and causing the balcony to leak.The sheet may have been weakened whilst cutting the waste hole although, as this product is much stronger in expansion than in contraction, it can crack across the sheet, when cooling down after a hot day, if it is fixed too firmly and unable to shrink back. Always ensure that manufacturers fixing instructions are followed.

The tiler seems to be respecting the work of the waterproofer as he has taken the trouble to cover the shower base with cardboard to prevent damage. Unfortunately, probably out of ignorance, he has also screwed batons to the wall to support his bottom row of tiles. These screws have penetrated the waterproof membrane and would void any waterproof warranty offered.

This balustrade is secured by screws inserted after waterproofing and tiling had been completed. The result is that the waterproof membrane must have been compromised. Better to use fixing bolts which as they are installed at substrate stage, can be included in the waterproofing system.
Do NOT settle for silicon sealing of fixing screws as this method almost always allows leaks to occur.