porcelain tiles coming loose

[crosscountryman]

Hello
I recently had a refurb on my kitchen and the builder laid porcelain floor tiles. A week after laying, 2 came loose which he replaced. Now 2 weeks later, another 2 have come loose. I also notice quite a few sound hollow when they are tapped - Im getting worried.
The porcelain tiles were laid on top of ceramic tiles, which were all sound. He put self levelling compound down first, then used a rapid set adhesive (don't know what type). Im worried more are going to come loose. Ive got 3 spare tiles left from the batch. Have I got a big problem? Im grateful for any comments. Thanks.

 

[mountford]

Need to find out if the adhesive he used has got porcelbond in it.

If they sound hollow it sounds like he hasnt got enough coverage behind the tile, get a coin and go round and tap the tiles if they all sound hollow then call the tiler back.

 

[crosscountryman]

Thanks.