I just bought a new apartment and have ceilings that were covered why what seems like concrete popcorn. My contractor didn't scrape away the "popcorn" and is skim coating over it. While the skim coating is not finished yet, it already has cracks all over the ceiling (see pictures). I mentioned this to my husband who is travelling, and he told me he had noticed a crack and pointed it out to the contractor who said the job wasn't done and they would recoat over it and sand the whole ceiling down. Is this normal? It just doesn't sit right with me.