Would be really grateful for any advice on this. So, I moved into a top floor flat in a 1960s flat-roofed block in March. The photos are of a crack in the bedroom. It runs from the window horizontally, along an external wall, then round the corner along the wall with the stairwell. From the stairwell side, you can see that part of the crack goes all the way through (the second last photo is from stairwell). You can also see a round area, both on stairwell side and bedroom side (some sort of previous fix?). The skirting boards look a little warped to me too (last photo). Is this going to be letting in water/a damp issue? If left as it is, will this mean higher heating bills in winter? Thanks so much!