Hey, we've been in our house a couple of years now, its not a new build, think it was built in 70,so maybe... anyways in the front room we've noticed where the window meets the wall in the bottom corner its cracked quite a bit and lets through a draught. There's also a hairline crack that runs diagonally from the corner of the window sill across the wall and then a third crack underneath the windowsill, central, running down towards the floor. This third crack is behind the radiator (not sure if this is a factor?) It looks like the previous owners had covered another crack that was in the top corner, but that has not re cracked, just an obvious cover up. Is this just general wear and tear of the house due to age etc? Or should I be worried about structural damage?