Not been in this exact situation myself... My initial thoughts are that by encapsulating he could potentially damage the AIB meaning it will need to be removed anyway? Of course this is dependant on the method of attachment, but he cant drill into it or damage it as it will release fibres. If it is in good condition, it could even be non licensed work (depending on how much is there http://www.hse.gov.uk/pubns/guidance/a0.pdf). It's another one of those 'on the face of it costs'. Consider the costs of these factors if he is going to encapsulate: - Requirement for REP / PPE for asbestos in case of damage - If AIB becomes damaged it will need to be removed and the whole are cleaned down - Costs of removal of damaged AIB are likely to be needed and are likely to be higher than AIB in good condition I think the costs of leaving it will quickly add up to more than the costs of removing it in the first place. I would suggest getting him to consider all related costs and go on from there. Of course, there is the other thing for the client to consider, how will he ensure that the AIB remains intact and is not damaged if he cannot see it? Hope that helps!