Hello, hope someone can advise me on this. Had extension built in 2018 and cracks started to appear around the rooflights after a few months. We put this down to movement but here we are 3 years later and it’s just getting worse and worse. The plaster looks blown where nails and screws have been used in the upright areas of the rooflights (not sure of technical term)! And cracks around the corners of rooflights are terrible. I’m reluctant to get builder back as he will say it’s normal (a phrase used a lot during the build when things were far from normal). I’d like to know where I stand and if I can just fix this myself or does it really need sorting by a professional? I’ll add pictures so you can see what I mean. Thanks in advance.