Hi Kurt, thanks for the reply. I see you saw my other pics! Ha this has stressed me out a little as you might have suspected. You believe that felt type pipe lagging is not asbestos? That doesn't really bother me as it is under the house and not disturbed. My only concern is the roof insulation, and if any is getting in to the house is it a concern to health, asbestos or not. Inspector comes next week. The roof area is used for storage. So the main beams of the house have (mostly) wooden boards running across the beams, and boxes of 'stuff' are sitting on top. Its possible the board has collapsed after all these years and so something has put weight on the board. Or its just an old house, which is slowly shifting down the hill and some cracks appear from time to time. The crack I sealed with glue, and then strips of paper and glue as a very temporary stop gap solution. All advice about mold on fibro sheets will be greatly appreciated!