Hi ,just wondering if anyone can help, we have recently had a two storey extension built and are worried about a few things, cracks keep reappearing both vertical and horizontal, these are only thread line but they are appearing on celings and walls both solid and stud walls, downstairs solid wall is slightly bowed with the floorboards bulging up in the middle of this room, this is in the origonal part of the house . stud wall is also bowed , the rest of the flooring seems to creaking and dipping everywhere ,3mm under light furniture ,also the up stairs floorboards are dipping in various places, and some rooms wobble in the old part, floor going into the upstairs extension visible sloops, have been assured that it's all just discrepancies ,is this right or should I be worried, any advice much appreciated