Insulating steel liners in internal masonry chimneys when relining

bholler said:

lots of the chimneys we are working on have had coal burn through them at one point

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I think this explains a lot of the differences between what you see in your experience and what Bother Bart is describing. Being in coal country, your business includes smaller flues used for coal stoves (and the nature of coal-burning seems to be tougher on flue tiles). Nationally, that is the rare exception, not the rule. In New England, for example, the vast majority of flue conversions in older houses are going to be from over-sized fireplace flues. Tile-busting would be far less needed.

oconnor said:

From my view, internal masonry chimneys with clay liners are very likely in need of a zero clearance liner install (I.e. insulation).

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I think it is also worth pointing out again: to many of us, our internal masonry chimneys with clay liners may SEEM to be NOT likely in need of a zero clearance liner install, since we are assuming the builders and masons did everything correctly. But given the lack of complete knowledge, insulating is well advised. And to be in full compliance with liner instructions, such lack of knowledge means insulating is required. (Unless we ourselves were the builders and masons, we can't really know what's behind the boards.)

BrotherBart said:

Opinion should be stated here as just that opinion. People reading these threads will tend to take statements by people in the business as gospel. And the statement I took exception to flat stated that the majority of liners are installed for damaged chimneys. Not that the majority that he installs are for damaged chimneys. People reading threads here do not need to be scared off from having a liner installed because they get the impression that it is going to mean not being able to revert to an open fireplace if they ever need to sell the house.

You guys in the business need to think about how your statements will be taken by other readers here. Yes it is about semantics.

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gotta agree with brotherbart .. when I read statement about why liner was installed. above is exactly the message that I got.

this forum is read from all over the world with chimneys of all different types and construction. newbies looking for answers quite frankly don't know what's correct from bogus information.

it's the vetting of incorrect information that makes forums one of the best sources for technical information. another requirement is traffic .. in order for vetting to be effective. there has to be enough eyeballs to contribute and vet information posted.

So are you/they saying that in the event of a chimney fire that the structure is going to get so hot, (and I do know how hot a chimney fire can get) that its going to breach the air space between the steel liner and the clay tiles, (realizing the liner may be touching the clay liner in some areas) radiate through the tiles, radiate through the space between the clay tiles and the bricks, radiate through the bricks and then be hot enough to ignite combustibles that might be present against the outside of the brick? Assuming tiles and structure are in good shape of course. Doesn't seem plausible to me...

I realy doubt it. To breach all those bariers. If so it would surely blow right by that thin insulation blanket too.

bholl, post: 1658452, member: 32126"]and I am sorry brother bart but how many liners have you done and how much training have you had on doing them buy qualified instructors? most of my info comes from csia recommendations as well as code and years of experience doing this. I have been doing it for 7 years and my father has been doing it 36.[/quote]
Not

bholler said:

I would like to add if your chimney is clay lined and there is not enough room for insulation break out the old clay. it is serving no purpose anymore and usually you are putting in a liner because the clay failed in some way. many times even if there is enough room for insulation but the clay is in really bad shape or really dirty we will break it out anyway to make sure the chimney is clean. and lots of times we find that the outside of the clay is almost as dirty as the inside.

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clay liners should be removed only as a last resort. homeowners should definitely not try this. a lot of chimney guys who've never laid a brick should not try this either. anyone can get CSIA certified its real easy. a tile breaker often breaks other stuff besides the tiles that you want to break like adjacent flu pathways, you could damage the outer structure of the chimney which may not be apparent if it is hidden behind a wall. I'm all for safety but telling somebody to remove all their flu tiles for safety? I mean why not just tear down the chimney and put in the metal bestest I mean at least then you'll know for sure it's safe

oconnor said:

I'm afraid the point of my original post is getting lost, so I'll say it again:

From my view, internal masonry chimneys with clay liners are very likely in need of a zero clearance liner install (I.e. insulation). This point tends to get missed in some threads I've read as they are focused on draft and reduced creosote.

The likely lack of clearances to combustibles outside the masonry structure is the main reason for concern.

In my case, my fully certified and experienced installer completely missed this issue, and I had a hard time sourcing the insulation as the suppliers rarely sold it. Here in NS it was, and may still be an issue of installers not educating clients of the need because they didn't want to raise the costs on estimates and lose business to guys who didn't know or care that it was an issue.

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many installers break furness flues and don't tell the homeowner. Hard too prove. will the insulation last. I've seen some pretty shoddy installation jobs. just because somebody certified doesn't mean they know what they're doing or there are honest

m.youtube.com/watch? v=NufFJaD060g
let's see what's behind this wall. Stone chimney built with rubbish.

oconnor said:

In not sure how one would confirm that an internal masonry chimney had a two inch air gap the full length of the structure. I think that is what Gulland is saying in his article for the CSIA. Especially in a fireplace.

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Here's how. I have a ranch with a attic pull down stair to inspect to my hearts desire. My basement is open ceiling.

fBig Dan said:

m.youtube.com/watch? v=NufFJaD060g
let's see what's beh

pen said:

The link doesn't work.


As far as future replies go: If this thread is to stay open, let's make sure responses are directed to the original poster's situation; pot stirring is best left to the kitchen.

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ind this wall

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pen said:

The link doesn't work.


As far as future replies go: If this thread is to stay open, let's make sure responses are directed to the original poster's situation; pot stirring is best left to the kitchen.

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if the link works it's a good argument for insulation. never assume it's safe. The pot must be stirred.

oconnor said:

Link should work here.

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thanks dude!