What's new

Chimney Liner

sdmuleman

Red Skull Member
Joined
Jul 29, 2020
Member Number
2385
Messages
306
Loc
Upper Marlboro, MD
How well does the mix and pour insulation actually work? House has 2 old brick chimneys - one is currently in use for the oil fired boiler and the other will eventually have a wood stove. Both are unlined brick and date from 1912. Inside dimension are about 9x9", and the longest one will be ~35 ft of liner. I like the idea of filling around the liner to help strengthen the brick word and have it completely sealed up. What I worried about though is how well it will actually work - from the videos I've seen it looks like it mixes to a pretty stiff paste and it would be very hard to get it to go all the way down and fill everything. Can you make it more of a soupy mix?

Also debating if I want to use flex liner or rigid - chimneys are relatively straight, but the flex liner looks like it may be easier to install and doesn't have joints to deal with.
 
Theramix works well, vibration sets the mix.

Think on this....
Easy fast and cheap
Or
Well done,time consuming,fair priced.
Pick one.
 
Corporate chimerica's mantra,
how fast can I make it cheap?
 
The hydro mix insulation rocks done right.
is a messy install, and takes time to pour,set,cure and temper "right".


I bet both homodepo and lowes knows, got peel n stick!
 
Theramix works well, vibration sets the mix.

Think on this....
Easy fast and cheap
Or
Well done,time consuming,fair priced.
Pick one.

Generally speaking when products that cure are involved you can get well done and dirt cheap if you're either willing to put up with chemicals so nasty it's not economical to use them commercially or willing to wait a fucklong time for it to cure.

:flipoff2:
 
Theramix works well, vibration sets the mix.

Think on this....
Easy fast and cheap
Or
Well done,time consuming,fair priced.
Pick one.

How much vibration? Do you need a vibrator tool? The instructions say to shake the liner or tap with hammer, but I'm not really confident that's going to work for 35 ft of chimney.....

Concur with doing it right and paying the time & cost involved, but want to make sure that I'm actually going to be able to get it installed and working correctly.
 
We used a rod to jitterbud each or every so many buckets worth, think 1' of lift.
You are not grouting block cells where ya need tight adhesion, just knocking out the air pockets.
The big thing is the base\start collar and how well it's sealed.
If mixed correct and done quick, it should be fine.
It is like hot syrup (fukkin sap suckers) and pours/flows out well.
You need to fill the masons excess on the inside walls is all.
Remember this is like ice around yer beerz= adds thermal mass and keeps the bottles from banging around.
The fitment of the liner is what flows the gas up and out.
 
We used a rod to jitterbud each or every so many buckets worth, think 1' of lift.
You are not grouting block cells where ya need tight adhesion, just knocking out the air pockets.
The big thing is the base\start collar and how well it's sealed.
If mixed correct and done quick, it should be fine.
It is like hot syrup (fukkin sap suckers) and pours/flows out well.
You need to fill the masons excess on the inside walls is all.
Remember this is like ice around yer beerz= adds thermal mass and keeps the bottles from banging around.
The fitment of the liner is what flows the gas up and out.

Do you have a picture of the setup you use? I don't have any sort of vibrator currently, and I'm not seeing how you could get something down that far in that tight of a space unless you put it inside the liner itself.

Thanks.
 
No pics, retired now.
We used a set of ss demo rods that wer in 4' sections with a drill motor, without the gad fitting.
In your case,being a 9" chase and guessing a 6" pipe...
either 6-7" is tight so if you can run a stick of 3/8 rebar in the corners to rod the mix, and try to go around all 4 sides as you go to settle the mix in go there.
if not best you will do is try and use the liner to move the material around (not gunna be fun) or last ditch, rod with 2 or 3 tennis balls attatched here and there run inside and bang on liner...

last ditch a coupple of guys in the sex toy thread got butt toys you can use
yea sorry
 
Last edited:
In your case,being a 9" chaseand guessing a 6" pipe...

Yes, was planning 6". Thought about 7", but don't think I need to. Right now I have a ~100k btu boiler, have a ~150k btu coal boiler to put in eventually, but looks like 6" should still be more than adequate.
 
I just (yesterday) finished relining my main chimney that serves a wood furnace and oil furnace with materials from rockford chimney supply. I used their rigid liner which is Olympia brand. I was lining an 8x8 clay flue which is about 7x7" inside and it was tight but worked fine. Once you get the clay liner clean, you can look down it and guess about which way sections need to lean at the joint to account for any issues with straightness of the existing liner. Mine had some bend and I didn't have much of a margin for error as the 6" liner is about 6.25" OD and the connection sections have areas that are 6.5". 8" level is your friend. The joints rivet together and it's really secure once you get 4 SS rivets into it. Air riveter is worth it.

The rigid is a lot thicker metal than the corrugated flex, which I used the insulated version of a couple years ago to line one of my other chimneys that serves an insert. The OD of the flex is bigger because of the corrugations for a given ID but it doesn't sound like you'll have issues anyway. That chimney was 12x14 or something huge so it was a really easy install the the insulated flex, think hotdog down hallway. That liner stays really clean, I never have to clean it. I'm not sure if it's because we don't heat with the lopi insert as much or if it's because it burns cleaner but it stays nice and clean compared to the wood furnace with clay liner. We'll see how the rigid liner does, I may wind up pouring insulation between the liners. I have a good seal between the liner and the clay liner at the roof to keep as much heat in as possible.

Check if the air space between your clay liner and masonry chase is needed. I can't remember the exact way the codes are written but I think you need an airgap that allows airflow to keep too much heat from transferring into any flammable materials around the masonry chimney. If you've got a bunch of blown insulation or foam around the chimney in the attic and the chimney runs right between trusses there's no way for the heat to get out of the trusses. The 1-2" or so of insulation that's between the liner and block is still going to allow some heat transfer and it will be a lot compared to the R40 of foam or blown in. You can add airspace by building something to hold insulation away from the block but I don't think any of the pourable insulations allow for zero airspace, I could be wrong.

I opted not to insulate so that some hot air goes up to the top of the chimney between they clay and stainless liner to keep the SS liner a little warmer and reduce creosote build up there. The top plate has a good seal and I wrapped fiberglass around the clay liner. I may change my mind and pour insulation in at some point down the road but I'm not sure. My chimneys are all in the center of the house so I actually get some heating of the house from the brick. It's surface temp is around 90F most of the winter. If your chimney is located on an exterior wall then you'll have to insulate, bad place for a chimney.

In your case I'd get 6" rigid liner with the snap on insulation wraps from rockford if you've got the room for it.

photo32519.jpg
 
fuck pour in garbage
eventually you're going to need to fix that fuckin' liner and you'll be mad at yourself when you do

run a liner, sure, but don't worry about the brickwork getting hot, remember that it just had the flue gas (from a horrible old and leaky, therefore extremely hot burning wood stove) going directly in it for a hundred years with no problem
 
Last edited:
[486 said:
;n198714]
fuck pour in garbage
eventually you're going to need to fix that fuckin' liner and you'll be mad at yourself when you do

run a liner, sure, but don't worry about the brickwork getting hot, remember that it just had the flue gas (from a horrible old and leaky, therefore extremely hot burning wood stove) going directly in it for a hundred years with no problem

What would you need to fix on the liner though? Shouldn't be any wear or significant corrosion, so what would need to be fixed? Big benefit to me is that it will also help stabilize the chimney since it's not exactly in stellar shape.
 
What would you need to fix on the liner though? Shouldn't be any wear or significant corrosion, so what would need to be fixed? Big benefit to me is that it will also help stabilize the chimney since it's not exactly in stellar shape.
they can fall apart in there, both the sectioned type and the spiral wound flexible stuff

87manche has a thread on here not that long ago about his adventures fixing one
 
[486 said:
;n198714]
fuck pour in garbage
eventually you're going to need to fix that fuckin' liner and you'll be mad at yourself when you do

run a liner, sure, but don't worry about the brickwork getting hot, remember that it just had the flue gas (from a horrible old and leaky, therefore extremely hot burning wood stove) going directly in it for a hundred years with no problem

Unless the clay liner has several cracks in it, I doubt the OP would ever need to replace it if he puts a rigid liner in. The liner I used has a welded seam with lots of overlap in the joints, it's not going anywhere without a massive chimney fire and even then the clay should take over blocking

The only time you're going to need to worry is if you have a chimney fire. Then if that clay liner is cracked the creosote has been leaking out through it creating a fuse to your house.

Chimney fires are absolutely no joke. I've been called to chimney fires with only a clay liner and the entire 2'*2' brick chimney chase was glowing red above the roof. If you have one that bad and aren't around to shut it down or call the FD there isn't much that can save the house but a good liner can make all the difference on a regular chimney fire. I've also been called to chimney fires with a rigid stainless liner in clay and aside from tossing an ansul bag into a big flame out the chimney, everything was fine.

They are hard to predict the outcome, keep your chimney clean!

​​​​
 
  • Like
Reactions: Clb
[486 said:
;n198780]
they can fall apart in there, both the sectioned type and the spiral wound flexible stuff

87manche has a thread on here not that long ago about his adventures fixing one

Not really unless you use a metal brush with a flex liner. The rigid stuff is thick and has a laser welded seam. Not going to fail. Hundreds of houses around here have it and I've never heard of it falling apart.
 
suppose I coulda been clearer on the "run a liner, sure" bit, maybe something like "for sure"
they do self-clean a lot better than the clay pipe, because they heat up enough to burn out a lot quicker
 
Not really unless you use a metal brush with a flex liner. The rigid stuff is thick and has a laser welded seam. Not going to fail. Hundreds of houses around here have it and I've never heard of it falling apart.
I'm picturing broken pop rivets and/or the holes they go in
stainless likes to crack, heat cycled stainless that's been cold formed, even moreso
 
[486 said:
;n198890]
I'm picturing broken pop rivets and/or the holes they go in
stainless likes to crack, heat cycled stainless that's been cold formed, even moreso

The whole works is supported from the bottom, in compression and the entire liner weighs maybe 100 lbs. There just isn't anywhere for it to go if it did crack at a rivet either. As long as it isn't exposed to multiple chimney fires the temps a liner sees are pretty mild. 500f maybe?
Empirical evidence would also suggest they are fine. I've never heard of one needing replacement.
 
The whole works is supported from the bottom, in compression and the entire liner weighs maybe 100 lbs. There just isn't anywhere for it to go if it did crack at a rivet either. As long as it isn't exposed to multiple chimney fires the temps a liner sees are pretty mild. 500f maybe?
Empirical evidence would also suggest they are fine. I've never heard of one needing replacement.
Yeah, only seen the flexible ones go bad, but just call me paranoid.
Also got a 40' piece of B-vent in a block chimney that I gotta do something with coming up coloring my opinions of the whole idea of cementing in a liner.
 
Fun read,
you naysayers should listen to the firefighter....
I haven't seen a flex liner leak until pulled on and then separated.
not near as good as ridgid.

And b vent wont take a flue fire like ridgid.
 
And b vent wont take a flue fire like ridgid.
I don't think this one's ever seen a wood fire, they did all sorts of real dumb shit in my house but at least not that.
well, the chimney itself has seen wood from the amount of soot on a few old holes in it, but the liner's only seen gas
still old enough to be rusty and unhappy though. Cemented in right down to the basement that I'm gonna fill in. Woulda liked to use it as a wood flue again, but might end up just knocking the whole thing out of there and put in class A rather than try and save it.
 
Unless the clay liner has several cracks in it,

​​​​

What clay liner..... 🤣 Best I can tell, there was never any sort of liner in either chimney. Currently all I have is a fuel oil burning boiler, so it burns clean, but quite sure there were at one point multiple wood stoves venting up said chimneys. Really makes you wonder how the house didn't burn down especially since there's wood directly up against the outside of the chimney and it's only a single layer of bricks.
 
[486 said:
;n198958]
I don't think this one's ever seen a wood fire, they did all sorts of real dumb shit in my house but at least not that.
well, the chimney itself has seen wood from the amount of soot on a few old holes in it, but the liner's only seen gas
still old enough to be rusty and unhappy though. Cemented in right down to the basement that I'm gonna fill in. Woulda liked to use it as a wood flue again, but might end up just knocking the whole thing out of there and put in class A rather than try and save it.

Run the class A through the brick.

Cautionary tales about class A:

Class A is nice stuff but MAKE SURE TO FOLLOW THE INSTRUCTIONS!!! Most, if not all, class A stove pipe still requires a 2" clearance to combustibles which I think gets ignored sometimes and causes problems. Up until this year I thought it was the 100% safe way to do a chimney, but our department got called to two chimney fires that were in fairly new class A stainless that resulted in structure fires in 2020. The first was in the winter time in the middle of the night way out in BFE. Took 20 mins from the call to get there and the fire had already gotten out of the chimney and burned holes in the 1st floor, 2nd floor, ceiling, and roof. Emptied all the water we had on the trucks and it didn't do much. By the time we got a good supply of shuttled water coming we were chasing it. While the house was still standing, everything was pretty much ruined but at least identifiable for insurance. The killer for me was that I'm sure the people that put it in thought it would eliminate the risk of the house burning down by spending that kind of money on the install. I have no idea what allowed the fire to get out of the pipe, the pipe was laying around in sections all over the place afterwards. A common occurrence in a chimney fire is a big sheet of creosote can fall of the wall and block the exit of the hot gasses and then they start traveling out any cracks or additional appliance connections. Or it can fall into the cleanout and get out into the basement and away it goes. I didn't see any spots where the stainless was burned through, all I can guess is that it either worked loose at a joint (is that stuff riveted or screwed after twist locking?) or more likely was installed too close to combustibles.

The second case happened this spring in a chimney fed from a sauna stove in a new home addition, built 2 years ago. All the stars lined up and we had water going on it just in time as the roof started to burn through in a couple spots. I was the first one there and was surprised to see fire around the outside of the triple wall stainless coming out of a wooden chase. I'm making assumptions based on what I saw while trying to slow stuff down by ripping the chase apart and spraying with the homeowners garden hose till the trucks showed up, but it looked pretty clear that the place had been poorly spray foamed and the foam was sprayed right against the chimney pipe. The pipe was also very close if not touching the t-111 chase. Once we had a plenty of water ready and ripped the ridge vent off and opened up around the chimney pipe my suspicions were confirmed. Zero clearance maintained from the pipe, fire started in the attic. If there hadn't been a chimney fire it would likely never have been an issue. If the pipe had proper clearance maintained it likely wouldn't have been an issue. But when stuff like that lines up, house fires happen. Saved most it, water damage in the addition but it was a serv pro and roofer situation. If the homeowner had hesitated to call 911 it would have been a total loss and they would have been brining in an excavator and a big waste management bin. This was new construction, done by a contractor.

If you've never seen a chimney fire, this is a good example of a mild one, like the second case I mentioned. https://www.youtube.com/watch?v=aRb4KthIPSI


I need to add a chimney in my house for the wood/electric oven range we put in the kitchen and I plan on using class A to do it, but I will likely run it through double wall pipe to make sure clearance is maintained through the attic. I think it's pretty common to maintain clearance by using some scrap wood to make a dam around the chimney to hold back blown in insulation but this never lasts, seen it.

Sorry for the rambling but the fear of chimney fire turning into structure fires are one of the few things that can keep me up at night. I sleep better knowing that all my wood burning appliances far exceed code and have redundant protection against chimney fire break throughs. I also clean my main chimney every 3-4 weeks, especially in the shoulder seasons when I know I'm not firing as hard and can be making more creosote. A lot of times the chimney will clean itself during the summer so make sure and check it with a mirror and clean the creosote out of the cleanout before you light the first fire.

Last note, if you have a chimney fire call 911 right away. If you notice smoke coming out of the roof or smell it in the house, call 911 back and let them know it's a structure fire. That can make a difference in the first response, especially in rural areas.
 
Last edited:
What clay liner..... 🤣 Best I can tell, there was never any sort of liner in either chimney. Currently all I have is a fuel oil burning boiler, so it burns clean, but quite sure there were at one point multiple wood stoves venting up said chimneys. Really makes you wonder how the house didn't burn down especially since there's wood directly up against the outside of the chimney and it's only a single layer of bricks.
Zero insulation means nothing gets all that hot? Maybe.
on one of mine a roof rafter is bolted directly to the cinder block chimney

If the bricks are not stable on their own you aren't going to stabilize them much by pouring something inside them, might even knock the whole mess down from the hydraulic pressure of the cement pushing the bricks out at the bottom if you're really unlucky.

Both of mine are chimney block, they're like cinder block but square with a big hole in the middle, might be an option if you want a masonry chimney. Run whatever liner in there.
Other option after knocking it out would be to frame it in as a modern chimney. I'd probably put several layers of drywall on the inside for fire protection but no doubt that's against all sorts of code for some reason or another. On you to research it and all.
 
Class A is nice stuff but MAKE SURE TO FOLLOW THE INSTRUCTIONS!!!

Sorry for the rambling but the fear of chimney fire turning into structure fires are one of the few things that can keep me up at night.

I'm way guilty of installing class A stupidly, if you look in my 1910 house thread near the end there, you can see I had to do some fuckery because I'd made the hole in the roof nearly zero-clearance and it was up against a rafter
Probably fuck with it more and get an actual roof thimble (or whatever its called) after reading your posts.
Was thinking about putting a section of 12" duct pipe around it, as it's an 8" OD class A pipe, but without any air movement in there wouldn't the outside of that pipe just get as hot as the outside of the class A? I know it'd keep the fucking mice from building nests against the "nice warm class A" with the blown in cellulose that the attic's full of. Maybe punch a bunch of 3/16" holes near the bottom so it can draw in attic air and exhaust up out the roof...

Wouldn't be able to run the A through the existing block chimney because the class b is cemented in there, gonna have to bust it up and restack the block. Certainly will try and salvage the blocks, though.

Was laying in bed thinking about how a liner could be cracked and filling the outer chimney with creosote, going to have to make sure my dad's checking for that on his. Assume you can pretty well tell by looking down between the two for collected poop buildup. We've always run that one way hot with dry wood, and it hasn't had any significant buildup any time we've looked, but the liner could well be cracked up near the bottom from how hot we're always running it.
I just got an insert off the side of the road not long ago and the adapter that fits in the top of it had more holes busted out of it than solid metal. Had that characteristic "way hot corroded stainless" look that catalysts get here in the salt belt.
 
I just lost 3 paragraphs:mad3:

So some of the pour in is as fragile as Styrofoam once set.
The old ? Ceramix? Was a ceramic \mortar type product looks like type s...

The stuff can be removed rather easy.
The start and termination collars are KEY.

Larboc great writeup man!
 
Top Back Refresh