The crack (horizontal, across the full length of the fireplace with about 3mm gap) has been there since we moved in over a year ago and has not deteriorated that I can see. Thought nothing of it until someone pointed out that it was unusual, and often a sign of sinking floor - which worried me a bit. Another person dismissed this explanation totally - both tradespeople but not really linked to flooring/fireplaces.
Anyone any views on this?
Anyone any views on this?