After 18 years why are my floor tiles buckling?

[up2you2]

On the first floor (not ground) my tiles seem to be lifting - see images.
When you tap them there is a hollow sound underneath, not on all but many of them.
This room is barely used, no construction nearby, so it is a complete mystery after 18 years they start to be lifting.
Checked today, these Cotto tiles are no longer available.
Considering waiting until they all lift, then resolving the issue then, million to one that anybody know how to speed up this process, without purchasing new tiles  please?

[OneMoreFarang]

7 minutes ago, up2you2 said:

On the first floor (not ground) my tiles seem to be lifting - see images.

 

What is under those tiles? Concrete? Or some wood construction?

Maybe the problem are not really the tiles but what is below those tiles. And to repair that could be a lot more expensive than just replacing tiles.

This is just a guess.

[Crossy]

It's called "tenting" for fairly obvious reasons.

 

Over the years the expansion space that was (should have been) left by the installers has gradually been used up due to natural movement of the structure. The stress in the tiles builds up until the adhesive can no longer keep them is place and lets go, often with a loud bang.

 

It took 50 years for the ones in the bathroom of our place in Rome to pop, scared me witless as I was on the can at the time 

 

You need to get a man in to lift the tiles, hopefully without damaging them, and re-lay.

 

[OneMoreFarang]

1 hour ago, Crossy said:

Over the years the expansion space that was (should have been) left by the installers has gradually been used up due to natural movement of the structure.

 

Can you please explain how that happens. If there was a floor i.e. 4m x 4m with tiles 20 years ago. What is the situation now? Not a flow with 4m x 4m anymore?

I understand that tenting can happen because of temperature differences. But if those tiles survived the temperature differences for many years, what changed now? 

[Crossy]

I would suggest that it's a fatigue failure of the adhesive from the temperature cycling (or other environmental changes), eventually it just gives up.

 

[carlyai]

Agree with Crossy, also:

One major problem I think is that Thai tile layers don't leave a big enough expansion joint between tiles.

Like in bricks and mortar, the mortar or joint should be the weakest point, so the joint can crack and not damage the brick or tile. 

So over time the filler between the tiles cracks and the tiles expanding push up at the joint.

I've got the same problem outside as well as tiles cracking because the ' yaa nails' is stronger than the tiles.

[up2you2]

Really appreciate your replies here - thank you.
Been at my wits end trying to work out what's really happening.
This room does get very hot with the sun as it's upstairs.

[degrub]

If there is wood product underneath, moisture intrusion swelling plus drying out cycling will do the same thing. 
 

But those tiles do look very tight for an area that sees direct sunlight most days.