Bathroom Tile Repair

This is a flat that my son bought in London, The bathroom tiles were known to be quite loose and the downstairs neighbour had complained about water seepage. On closer examination on moving-in day they were found to have a gap at about row 6 of about 15mm between tile and wall! Many of the tiles came off with the fingers. The gap reduced up to row 12 where we felt they were sufficiently well attached to be safe.
Approx 130 tiles were removed, about 20 of which were broken in the process. It was obvious that the void between tile and wall had almost filled with shower water. Very little of the adhesive was attached to the plaster.
The plaster was found to be softened by the water for the lowest 25mm which was scraped out as mud and the whole left to dry.
PVA diluted 1:3 was painted onto the dry plaster to increase its integrity and to assist adhesion.

The gap near the bath where the plaster had washed out was repaired using Ronseal epoxy (wood) filler which sets to any depth in about 5 minutes.
It is very fortunate that the previous owner had found the remains of a box of new tiles, as none of the suppliers we contacted had any record of these still being manufactured or stocked.

The old tiles were heavily backed with old adhesive and it would have been a nightmare to try and clean them without a special jig and a bench, so we used up the new ones first. We fixed them two rows at a time starting at the top, using wood battens. The battens had a line marked on using a marking gauge to indicate the correct level for the bottom tile row of the two rows. We used several battens bacause each one was progressively longer!
The adhesive manufacturer recommended against comb-laid adhesive (which these tiles had been fixed with) and advised a solid 3mm bed of adhesive. It was quite obvious that the comb marks had allowed the water easy passage down the backs of the tiles, like little channels, especially as the joints were as thin as a filling knife blade and has very little grout. As we had to stick the tiles at the same level as their neighbours i applied more than enough adhesive, then slid each tile horizontally, taking out any extruded adhesive from the joint, until the tiles came down to the right level.

After the first weekend I took the old ones home and spent a couple of mornings scraping the adhesive off them - approximately 80 tiles! Using a jig made from a sheet of 18mm chipboard with three laths of 4mm ply in the shape of a tile, each tile was safely held whilst scraping the adhesive off the backs.
The very important piece of cereal packet glued to the centre of the jig stopped the tiles from cracking in two under pressure, because each tile front surface was slightly concave.
An ordinary wood chisel was used, and reground on a Tormek every five tiles.

On the second weekend we were able to complete the tiling, and after a day to dry out we grouted as thoroughly as possible, and applied a new silicone bead.

Bathroom now beautiful again!