ᐅ Tiles are lifting extensively across the bathroom floor.

In a small bathroom, the floor tiles are lifting extensively over an area of 3 square meters. This started from the outer wall and has now reached the door. The wall is not a direct exterior wall because it was built out due to the sloping roof.

- A test tile was easy to lift. There is no visible moisture under the tiles.
- In two toilets and two other bathrooms, covering a total of about 15 square meters, the tiles are stable.
- The floor is lifting in the attic studio; the ground floor and first floor are stable.
- Years ago, a roof window was left open during rain.

- Floor construction: concrete slab, screed

- Could movements of the roof structure cause the lifting?
- It is interesting that two rows of tiles in the middle of the room have lifted in a tent-like shape continuously from the wall toward the door.
- The screed was laid over a large area without an expansion joint. I am not aware if there is an expansion joint at the door.

What could be the cause?

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

Could there have been frost in the room at some point?

It is also possible that the adhesive fails after 30 years. Not everything was better in the past.

rick2018 schrieb:

It is also possible that the adhesive fails after 30 years. Not everything was better in the past.

I also suspect that the adhesive contains an elastic polymer additive, which has now given way to material failure.

Old tiler’s wisdom: "Tiles last either 3 or 30 years." So, I would also guess that the adhesive has failed.