My oil-fired boiler needs replacing due to corrosion. It has an asbestos cement flue rising through the flat above and the attic. Is it permissible to re-use the flue, or does it need to be lined or replaced?
If the flue is in good condition physically and there is no need for repair from a performance standpoint, then it is permissible to keep in place and re-use. However, this may present an opportune time to replace it from a cost-savings standpoint since you will already have the boiler out so accessibility will be good and the unit will already be taken out of service. Sometimes asbestos building materials can present financial liability at the time of property sale, so if you would consider abating the flue for that purpose, then this could be a good time to do it. If you're looking for the cheapest short-term solution, just keep it in place as long as it's in good condition and meets the necessary specs for your replacement boiler's venting requirements. A visual inspection to verify physical integrity would be a good idea.