Couldn't believe it either but boy were they stuck. SDS was no good as the Silicon took the impact so had to smash it into a million pieces & dig in with a Mutt & 150mm Hamilton
Not good. I bet they didn't sound as hollow as you'd assume either then. Silicon would take the impact from the coin test too and make it sound a bit duller than you'd get with adhesive.
Suprised the grout held up though. It's a vote of confidence for whatever make that was!
They didn't sound hollow at all. Even at the pan where they were cracked. I had priced to uplift them if fitted the correct way or near enough. Normally would have had it all up in about half an hour. Took me a whole day! Couldn't even let the customer know as he was abroad so just I took the hit on it.
The grout must have been mixed with a latex to hold up to that
I've posted these before I think, dot and dab over UFH, 1200x600 porcelains. Was only there to replace a couple of loose tiles, ended up ripping the lot up and starting fresh.
They were put down in 2008, customer bought the house last March, I found the house on Zoopla and they paid 950k for it, there is approx 300 m2 of tiling all fitted like this, it's only a matter of time before it all fails.