Insulating a liner

[adkww]

I am going to go with a ss flex liner in my existing block chimney. Problem I have is that the top half (10 feet or so) of my chimney is missing the flue liner as I removed it because it was damaged, but the remaining 13 feet down has the 8x8 clay liner still there. Talked to the rep at Rockford and he said I could pour down vermiculite to fill in the gap on the lower half to insulate and go with the blanket wrap on the top half of the liner thereby ensuring the liner is insulated from top to bottom. Seems reasonable since the top half is where insulation is really critical. I don't want to get into the job of removing the existing flue tile especially since it is pretty far down and why open up a can of worms possibly by damaging the existing structure when trying to remove it. I have seen plenty of folks who just run the ss pipe thru the clay tile and use the poured in insulation. Trying to keep it as simple as possible. Can I just pour in vermiculite (or peralite) to fill in the below cavity? I would pour the insulating material once i got the ss liner in place and obviously the insulating material would go between the new liner and existing clay tile but also would flow between the outside of the clay tile walls and the inside wall of the blocks. Anyone see a problem with this? I figure I'd ask you guys here as I have read a lot of great advice over the years on this site. Thanks.

 

[Batman]

Seems legit, but are you sure that you can't fit insulated liner (blanket) down through the 8x8? Should outfall fit, and would be less mussin and fussin'.

 

[Batman]

Auto correct! Grrrr!

 

[bholler]

do you have the required clearances between the outside of the chimney and combustible materials in the bottom section if so your plan is perfectly fine if not i would have the rest of the old tiles removed and insulate either way with pour or blanket wrap. If you have proper clearances you could do what you propose or just use pour in the whole way up no need to switch

 

[adkww]

Rep told me it probably wouldn't fit into flue tile with insulation wrap as the inside dimension of the flue tile is 6.75 x 7". Its close and I though since I only had to go thru 13 feet or so I could make it but I would sure hate for it to get stuck or to buy all 25' of wrap as it is quite expensive.

 

[adkww]

do you have the required clearances between the outside of the chimney and combustible materials in the bottom section if so your plan is perfectly fine if not i would have the rest of the old tiles removed and insulate either way with pour or blanket wrap. If you have proper clearances you could do what you propose or just use pour in the whole way up no need to switch

What do you mean by the bottom section? My chimney is 2" away from the side of the house and sits on its own pad. Runs up the side of the house and maintains the 2" distance. Wood stove exits thru the wall and directly into the side of chimney.

 

[Sawmonkey]

I've done the blanket wrap before. Not too bad, wrap the blanket around the liner, and I've used a thin metal mesh deal that slids over the wrapping acts like a sock and then bailing wire around that super tight to hold everything together and send her down. Don't like vermiculite because it has asbestos in it. Unless it's only in the stuff made way back when

 

[bholler]

What do you mean by the bottom section? My chimney is 2" away from the side of the house and sits on its own pad. Runs up the side of the house and maintains the 2" distance. Wood stove exits thru the wall and directly into the side of chimney.

If you have 2" to combustibles you are fine just insulate as much as you can for performance reasons And no it wont fit in the old flue wrapped.

Don't like vermiculite because it has asbestos in it. Unless it's only in the stuff made way back when

Vermiculite only had asbestos in it form one mine which is no longer used. The pour in insulation is a good product but it takes some experience to make sure it is evenly distributed

 

[Sawmonkey]

If you have 2" to combustibles you are fine just insulate as much as you can for performance reasons And no it wont fit in the old flue wrapped.




Vermiculite only had asbestos in it form one mine which is no longer used. The pour in insulation is a good product but it takes some experience to make sure it is evenly distributed

Thank you. I didn't know all the details with that , I had just heard about it awhile back

 

[adkww]

Thank you. I didn't know all the details with that , I had just heard about it awhile back

When pour in insulation is mentioned is it the special mix the liner company sells where you add water or just plain vermiculite (or perlite)? Btw, What is the difference between vermiculite and perlite?

 

[bholler]

Yes it is the mix plain vermiculite is no longer recommended

 

[fire_man]

I don't like the mix which hardens up - what if you need to "tweak" your setup due to installing a different stove or for some other reason? The hardened stuff can be broken out but what a pain that would be.

 

[bholler]

no it really is not a pain and it is easier than pulling it out of packed loose fill. It comes out with a simple rotary cleaner. All that and loose fill is simply not tested or approved for chimney insulation

 

[fire_man]

How the heck does a rotary cleaner work? You've got maybe an inch of hardened mix between the pipe and clay liner all the way around the pipe. Is it like a giant long flexible drill bit?

Then you have to drag all that crumbly stuff out - seems like a lot of work when a blanket would work most of the time.

 

[CenterTree]

Rep told me it probably wouldn't fit into flue tile with insulation wrap as the inside dimension of the flue tile is 6.75 x 7". Its close and I though since I only had to go thru 13 feet or so I could make it but I would sure hate for it to get stuck or to buy all 25' of wrap as it is quite expensive.

It would NOT fit with insul blanket.

I assume you are installing a 6 inch liner?? Figure 6 inch, (6.25" if it is heavy duty or smooth wall),
plus a half inch of wrap would add another 1 inch of diameter.
Then your wire mesh sleeve adds a little more. Too tight. You may have protruding spots of mortar inside the chimney also. (making matters worse).

How much inner diameter do you have in the top section? (where the clay was removed)?

 

[adkww]

It would NOT fit with insul blanket.

I assume you are installing a 6 inch liner?? Figure 6 inch, (6.25" if it is heavy duty or smooth wall),
plus a half inch of wrap would add another 1 inch of diameter.
Then your wire mesh sleeve adds a little more. Too tight. You may have protruding spots of mortar inside the chimney also. (making matters worse).

How much inner diameter do you have in the top section? (where the clay was removed)?

On my upper 10' or so section it is the inside dimensions of the cement block, which had accommodated the 8x8 flue tile with about an inch gap to spare on all four sides so I have lots to play with up there, hence the blanket option. 10 feet down from there is where the flue tile starts.

 

[bholler]

How the heck does a rotary cleaner work? You've got maybe an inch of hardened mix between the pipe and clay liner all the way around the pipe. Is it like a giant long flexible drill bit?
Then you have to drag all that crumbly stuff out - seems like a lot of work when a blanket would work most of the time.

By rotary cleaner i mean tools like the soot eater the stuff does not set up very hard at all and regular cleaning tools will clean it out. And yes it needs cleaned out the bottom then. There are advantages to both systems and we use both it just depends on the situation. We use pour in on oil or gas furnace chimneys where we drop a 6" down inside the old clay and there is no room for wrap. Or where it is an old brick chimney that is in bad condition on the inside the mix stabilizes the interior. For inserts we generally wrap the liner because there is plenty of room and there is more of a chance that someone would want to pull the liner out and go back to the old liners. Not to mention that it would be a ton or mix to fill the large space

 

[bholler]

On my upper 10' or so section it is the inside dimensions of the cement block, which had accommodated the 8x8 flue tile with about an inch gap to spare on all four sides so I have lots to play with up there, hence the blanket option. 10 feet down from there is where the flue tile starts.

Yeah like i said before your plan is fine or you could just fill the whole thing with pour in wich is probably what i would do

 

[adkww]

Well, I actually removed all the liner today - from the inside of the house after contemplating how I could remove all 23 feet from the top of the house. I did remove the top 10' last week working from the top of the house but I gave up after finding it very difficult to remove anymore tile from above. I even tried to find places to rent a tile breaker but no such luck. When I first installed the chimney I made sure the clay liner did not touch the inside of the blocks - it floated all the way up - and now it made my life a whole lot easier when I removed it today. I used a long pinch bar and busted the clay tile from inside the house and each time the whole stack settled downward and I carefully reached in and pulled the broken pieces out from my living room. Have some pics from the top now that its done. Thanks to all for the help as I have learned a lot in the few weeks since joining this site. What a great site! Now I can go with a 6" liner for my Jotul F500 stove instead of a 5.5" with an insulation wrap from top to bottom as the interior of the block is about 9" square and will now easily accommodate pipe and insulation wrap. I'm thinking now of going with the single wall 316Ti rather than the double wall since many of you did not like the double wall pipe. Is it better to just go with the light duty single wall flex rather then the HD version? From what I have read the plain and simple single wall liner will work fine plus the price is great. I'm looking at Rockford and Chimney liner depot. They are both close, one is free shipping but the liner is slightly more expensive. Overall they are pretty closely matched in price. Can't wait to get this stove working again. Cold here right now! That blasted furnace keeps running. I don't know how folks without stoves manage to get through a winter.

 

[bholler]

I prefer heavy wall over either light or the double wall stuff but regular lightwall would be way better than the double layer stuff. Nice job breaking it out i am sure it was a real pain without the right tools