I am looking at an 'as is' house to buy. Built in 1956, it has this cement/asbestos flue pipe for the furnace/hot water heater exhaust. It does not appear to be fryable (seems solid). I will have to replace the steel from the top of the flue (in the attic) to the through roof fitting. Is there any problem just leaving this pipe (the Transite) in place or could it be a nasty headache in the future for resale etc.?