Question: Does flexible and rigid stainless liner pipe require some type of wrap around insulation to keep your flue warm for proper venting if it is used in an inside masonry chimney for relining? It seems to me that even though our chimney has a terra cotta liner in it stainless steel dropped down would be hard pressed to hold it's temp like a Dura-vent chimney might. Or maybe IÕ way off base. Answer: As far as insulating the stainless steel, there are two sides. In a more temperate climate, like here in South Jersey, we have done fine with the uninsulated pipe. Even without insulation, the resulting job is much better than before due to the air space around the pipe and the smaller diameter. The insulation wrap might be a good idea with external chimneys in colder climates, especially if the lining is being done because of chimney fires resulting from excess creosote formation. Some insulated chimneys are air insulated and some are wrapped, and they both work well. Keep in mind that newer stoves generally do not produce the amount of creosote and tars as older ones, so excess formation in the chimney is not as much of a problem. Also be sure to look at the specific brand of liner. Some require the insulation to meet UL standards. Ask for a copy of the installation instructions or download them from the manufacturers website.