new installer say not to insulate

steviep said:

I had another installer come out and look at installing a 6 inch ridged liner in my exterior 8x8 clay lined chimney. He says it will be fine without insulation . He will install it with insulation but it means breaking out the clay tile, whitch he feels more damage than helping the block part of the chimney. Its only a 500 dollar difference between insulated and non insulated. He told me that he doesn't really find much diffence in creasote build up between the 2 . Just so yuo know he also does masonay chimneys and does chimney sweeping.

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billb3 said:

If your existing clay liner is in good shape and installed correctly ( not upside down or missing sections) .
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Absolutely, if there are problems with the clay liner, better to be rid of them now. Waiting means destroying what you do to compensate for them to fix them later.

If it is not in danger of having a creosote fire now, it's hardly likely that it could posibly be more likely to have a creosote fire with a rigid liner.
Maybe inside the liner - but that's a different issue.
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The scenario I suggested in my original post comes from the "real world" of my cousin who runs a shop and installs liners and wood burning appliances. They've had customers who have installed an uninsulated liner in a used chimney system. The existing clay liner was not cleaned well and they had a chimney fire in the new liner. The extreme heat generated caused the creosote on the old clay liner to ignite. This resulted in smoke flooding back into the home around the thimble and caused smoke damage and odor for months afterward. One fire actually extended through a gap in the clay liner and brick into the home and did 10's of thousands of dollars worth of damage to the house. Other users have simply had "the smell" come back through the thimble into the house from the old chimney... I imagine there must be many who had none of these problems after putting an uninsulated liner into an existing clay tiled chimney. No problems at all, ever. That doesn't mean they won't, or that it's the way it should be done.

My cousin and his partners will not install an uninsulated liner in a used chimney unless it has been cleaned meticulously and inspected. Then they warn the homeowner that they risk having the odor problems. It's cost them some jobs, but they don't get called back to fix things later. They also don't get claims against their insurance and complaints to the better business bureau because of shoddy work either. Sometimes people crab down to the coffee shop about them refusing to do shoddy work. Oh well... if you can afford to do a job two or three times and repair damage resulting, then you can afford to do it right once.

No way would I let someone knock out perfectly good clay tiles - may as well tear the chimney down - to have the mortar fail and have cold air coming in ? - no thanks.
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Perfectly good is an assumption unless it is closely examined with a camera, especially when it comes to clay tiles. If they were perfect and clean, I wouldn't knock them out either. Sealed at the top, the airspace around the new liner will provide excellent insulation against heat loss from the new liner system.

More insulation is almost always better, but I wouldn't remove what I already had. (unless there was a problem with it)

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