l'm planning to knock down my living room wall to make it open plan into the hallway/stairs.Could someone tell me, how you can tell for definate that the wall l,m planning to take down is not surportive.l,m know by looking at the floorboards upstairs and telling which way the joints run should tell, but is the only factor you need.EG.. wall runs same direction as joints are not surportive so this is ok to take down.