Hi, my home is quite old so when stripping the walls all the original lining paper came off. The wooden panels are also quite brittle. I have lined the walls, filled in the joints and PVA the walls before doing so. I painted the lining paper, but know with the hot and cold weather the joins of the lining paper are separating. This looks like a tear on the walls. I have tried filling with a soft polyfilla and repainting the joins but they still come apart. Help!!