Hi , I'm looking at buying a house and thought I'd have a look in the attic. Upon inspection I noticed the felt or sarkin seemed to have been clout nailed on the inside in between the rafters. A lot of it is sagging and falling down and you can see daylight through the tiles. The roof is slate and the house is a pre war 1940s semi. I'm not sure if this just needs fixing back up or the whole of the slate tiles taking up and new felt going i too of the rafters. Please dee photos. Thanks.