I've just bought a house that has had previous subsidence. A number of the artex walls and ceilings have developed hairline cracks along the joins in plasterboard . I'm not bothered about the cosmetics as will deal with in the fullness of time but worried about safety with kids in the house, that the cracks will give off artex asbestos fibres. Is it safe as is? And, for peace of mind I wanted to coat the crack with some zinsser sealer and fill it with calk. Would this be advisable? One of the rooms it is in will be my newborns bedroom so want it totally safe