I had a full house survey some years ago, a very short time after moving in woodworm was found by builder carrying out work. The surveyor had not spotted this and it was very obvious wood worm in the loft so building society had to fund the remedial wood worm treatment. At the time I did not know I could or consider asking for another survey on the roof. Now there are issues with lack of supporting timbers so roof is sagging. Question is how long do I have to go back to building society and raise this issue. I have been told by roofing contractor it should of been picked up on the survey. Thank you for your input.