Just something else to look out for make sure he use's a flexible, bagged adhesive ie that heJust to say, thank you for confirming my gut feeling. I've advised him they all need to come off and I've had to buy a new lot to replace them. He seems okay about it. But having had some input from another professional has helped me be firm about it.
has to add water to and mix up and not a ready mix from a tub amd he primes the walls first..