Insulated SS Flex Flue Lining

[tasteliss]

I purchased a home with a 13X13 clay flue lining that is 24 foot high and located in the center of the house. The fireplace is located in the basement and the chimney was inspected and OK to use with the fireplace.
I plan to install a wood stove and will reline the chimney with a 6 inch SS flex flue lining. I plan to insulate the top cap and insulate the block off plate.
The idea is not to insulate the SS flex flue and allow the SS flue to heat the clay liner and help heat the house with the radiant heat from the chimney.
Is this SAFE and does it meet most building codes.

 

[spirilis]

I'm pretty sure it is, however I believe those SS liners don't radiate much heat since they are made of shiny metal on the outside... i.e. low emissivity. So don't expect stellar amounts of heat to radiate from the flue to the chimney structure. I'm sure some will though. The air between the SS flue and the clay will heat up and that'll offer some heat (good that you're insulating the top & bottom). But using an uninsulated liner shouldn't be a problem, i.e. your draft should still be awesome due to the fact that the chimney is interior to the house and 24ft is a nice tall flue.
(not an expert on this, just summarizing what I know from countless hours of reading hearth.com :D)

 

[BrotherBart]

If the chimney tiles are in good shape it will be fine. I am running a twenty-one foot and a thirty-three foot liner installed exactly that way in exterior chimneys.

And I disagree on the lack of heat radiation. A .005 thick stainless steel tube with a five hundred to a thousand degree exhaust running in it gets danged hot. Shiny on the outside or not.

 

[EJL923]

You will not get much if any heat from the interior chimney, so dont count that as a factor.

 

[Benchwrench]

code says you don't have to insulate your liner since you have an interior chimney I agree with ELJ and not to expect any significant heat from what you're asking because I doubt you see the clay liner but it's wrapped in brick or stone.
I am one of those that are of the opinion that wouldn't seal/insulate the top plate

 

[tasteliss]

Thanks for the info.
Ron

 

[Rob From Wisconsin]

From personal experience, I have to disagree with most of you.
Our lined flue emits quite a bit of heat. In some ways it almost behave
like a masonry heater - it stays warm for many hours after the fire is gone,
and does significantly add to our overall heating.

 

[begreen]

Had an uninsulated, rigid liner in our chimney before I pulled the fireplace. No block off plate. When the insert was burning 24/7 there was a lot of warmth coming off that chimney. I know because they plastered over the brick along the stair case. I would feel it every night going to bed and every morning coming downstairs. After a day of burning I would guess the temp to have been about 110-115F.

 

[leeave96]

The only problem I see with sticking an uninsulated liner down a tile lined chimney is that once the liner is in there, you can't inspect the chimney for cracks. If you have a flue fire with an uninsulated liner, you may be to close to combustables. Further, legacy cracks that may be imbedded with creosote might fire off - causing a house fire. Insulation around the liner ought to eliminate that potential.

Just a thought.

Good luck,
Bill

 

[fossil]

The trade-off, of course, is the "health" of the exhaust gas stream going up the flue to daylight. The more lateral heat transfer is allowed to occur along that vertical path, the higher the probability that the gases will, at some point, cool to below the boiling temp of water where you live, and thus lead to creosote condensing out lower than it otherwise would (if at all). An insulated liner will guard against this. Yeah, it's sort of a double-edged sword...we want to extract as much heat as we can from the system, yet the system needs to retain at least some heat in the exhaust stream to help keep the flue clean and safe. Rick

 

[csierotnik]

I have almost the same set up. 24 foot chimney / interior / clay liner. I insulated my liner for peace of mind - just because I coudn't tell what was touching the chimney behind the walls. I guess its a personal choice and what you feel comfortable with.