Hi all.
4 years ago I tiled walls and floors on a new timber framed house over here in SW Ireland .
About 18 months later cracks started top appear on some floor tiles about 4 inches from the walls . After a lot of investigation it was discovered that the builder had built the foundations for the ( large ) timber frame using block placed on their side rather than upright as the plans showed. Inside the block founds insulation was laid with underfloor heating attached and then a slab of concrete poured over it. What happens now is that the founds and the slab are not connected and depending on the water table and/or ambient temp the slab either lifts or drops by a tiny amount. Due to the fact that the tiles bridge this join about four inches from the wall the tiles shear.
The owner accepts this but the resulting broken tiles destroy the lovely floor.
I came on here to ask if any of you are aware of or can recommend an adhesive that would move the 1 or 2 mm max that is causing the problem. The worst area is a lower ground floor tiled in 8 inch terracotta . We still have spare tiles so a repair is possible.
Thanks in advance .

The only adhesive i have seen that is really flexible is a rubber crumb 2 part. However could you not add an expansion joint and incorporate it into a border around the edge? I doubt a decouler would work as its vertical and not lateral movement.

A movement joint is the way to go..

Movement joint for me too

Welcome to the forum

Hi and welcome

Movement joint would be your best bet