@43d7c4ea This isn’t the first problem with concretes. In the early 1960s the lovely post war school I was in had to be closed for remedial work because the school hall in a similarly school had had a whole roof collapse. Then there was the whole thing with High Alumina Cement in the early seventies, similarly affecting public buildings and motorways like the M6 at Gravelly Hill. I seem to recall people went to prison for that.