Hello, my parents house has some weird holes appeared above the skirting boards. I can't seem to attach a picture. The holes are about golf ball size and like a bullet has been fired through. They are along one internal wall which goes through the middle of the house. The holes are about 1.5m apart and also appear on both sides of the wall. It continues past a doorway as well. Can anyone advise what this is? There is a vertical crack in one bedroom above this said wall. The house is a main road and upstairs shakes as lorries go by. Thanks in advance.