Tiles lift extensively from the bathroom floor

In a small bathroom, the floor tiles on 3 square meters have lifted extensively after almost 30 years. It started from the exterior wall and has now progressed up to the door. It is not a direct exterior wall, as the wall was built forward because of the sloping roof.

- A test tile could be easily lifted. No moisture is visible under the tiles.
- In two toilets and two other bathrooms, a total of about 15 sqm, the tiles are stable.
- The floor is lifting in the attic studio; the ground floor and first floor are stable.
- Years ago, the roof window was once left open during rainy weather.

- The floor structure: concrete ceiling, screed

- Could movements of the roof structure cause the detachment?
- It is interesting that two rows of tiles in the middle of the room have tent-like lifted continuously from the wall towards the door.
- The screed was laid extensively without expansion joints. Whether there is an expansion joint at the door is unknown to me.

What could be the cause?

The glue is no good. It doesn't even stick to the tile.

Was there possibly frost in the room at some point?

It is also possible that the glue gives out after 30 years. Not everything was better in the past.

It may also be that the adhesive gives up after 30 years. Not everything was better in the past.

I also suspect that the adhesive contains an elastic plastic additive, which has now succumbed to material failure.

old tiler’s wisdom: "Tiles last 3 or 30 years." So I also guess that the adhesive has given up.