Remove old liner?

[JustinMN]

I feel this is dumb question that I know the answer to but I figured I’d ask before I tear anything out just in case.

I have an existing metal liner in my clay flue that my old, traditional-style fireplace used. The liner is big enough to fit my new liner within it (insulation and all) but the old liner has screws protruding about a 3/4 of an inch into the center of it.

I’m afraid if I remove the old liner, there will be too much space between the walls of the clay flue and my new liner’s insulation. I haven’t assembled my new one yet but I’m going to estimate and say there will be about 1.5” of space around on all sides of my new liner once installed. ’m also afraid that if I don’t remove the liner that I’ll have to figure out how to grind down those screws so it doesn’t destroy my insulation.

Would it be best to just remove the old liner before installing the new one? If so, do I need to do anything else to ensure I get a good draft? My chimney is about 30’ tall, is on an exterior wall but the chimney itself is within the wall (can’t be seen running up the side of my house) and the only piece you can see outside is about 4’ of it sticking out above my roof.

Of course I have a 14”x14” piece/plate that will cover the top of my chimney but wasn’t sure if I’ll still need to acquire more/special insulation to plug any holes.

Thank you!

 

[bholler]

I feel this is dumb question that I know the answer to but I figured I’d ask before I tear anything out just in case.

I have an existing metal liner in my clay flue that my old, traditional-style fireplace used. The liner is big enough to fit my new liner within it (insulation and all) but the old liner has screws protruding about a 3/4 of an inch into the center of it.

I’m afraid if I remove the old liner, there will be too much space between the walls of the clay flue and my new liner’s insulation. I haven’t assembled my new one yet but I’m going to estimate and say there will be about 1.5” of space around on all sides of my new liner once installed. ’m also afraid that if I don’t remove the liner that I’ll have to figure out how to grind down those screws so it doesn’t destroy my insulation.

Would it be best to just remove the old liner before installing the new one? If so, do I need to do anything else to ensure I get a good draft? My chimney is about 30’ tall, is on an exterior wall but the chimney itself is within the wall (can’t be seen running up the side of my house) and the only piece you can see outside is about 4’ of it sticking out above my roof.

Of course I have a 14”x14” piece/plate that will cover the top of my chimney but wasn’t sure if I’ll still need to acquire more/special insulation to plug any holes.

Thank you!

View attachment 303320

I would pull it

 

[EatenByLimestone]

Me too. I don’t see how the screws wouldn’t tear up the insulation on the new liner

 

[JustinMN]

Me too. I don’t see how the screws wouldn’t tear up the insulation on the new liner

Thank you! I agree that I don’t see how it wouldn’t tear it up. I was wondering though if someone was going to suggest I get a different liner with a larger diameter or something.

Do you think it would cause issues if I doubled-up the insulation wrap on the bottom few feet of the liner just to ensure it’s more sealed?

 

[JustinMN]

I would pull it

Thank you!

 

[EatenByLimestone]

I would put extra insulation above the block off plate, and also at the top 4 feet of the chimney, the part that sticks out above the roof.

 

[Mo Lake]

On a similar topic. I just removed a wood insert from my chimney as I was unable to have it swept due to a welded baffle so converting back to a wood burning fireplace. The guy removing it said the liner has to be removed to burn. He is sketchy as I have been waiting for 3 weeks for him to pull the liner although he took the stove away and installed the new glass doors. To remove the cemented-in liner, what do you recommend to do? Drill holes and chisel? I was looking to find options to retain the liner but can't find any pans for the base of the liner to block the chimney except for the liner hole. Thanks!

 

[bholler]

On a similar topic. I just removed a wood insert from my chimney as I was unable to have it swept due to a welded baffle so converting back to a wood burning fireplace. The guy removing it said the liner has to be removed to burn. He is sketchy as I have been waiting for 3 weeks for him to pull the liner although he took the stove away and installed the new glass doors. To remove the cemented-in liner, what do you recommend to do? Drill holes and chisel? I was looking to find options to retain the liner but can't find any pans for the base of the liner to block the chimney except for the liner hole. Thanks!

The liner most likely isn't big enough anyway it will need to come out then the old one inspected

 

[Mo Lake]

Any recommendations as to how to remove the cemented in liner without damaging the clay pipe? I think this guy stiffed me so will need to do it myself. Thanks.

 

[EatenByLimestone]

You may be able to cut some of it with an angle grinder, but I think a chisel will be your best bet.

 

[bholler]

Any recommendations as to how to remove the cemented in liner without damaging the clay pipe? I think this guy stiffed me so will need to do it myself. Thanks.

Cemented just at the top? Or the bottom? Or the whole thing?

 

[mellow]

Guessing it has pour in place insulation.

 

[EatenByLimestone]

I looked back at the liner pic at the beginning and it doesn’t look like pour in. I’m hoping the installer just cemented in the bottom.

 

[mellow]

I looked back at the liner pic at the beginning and it doesn’t look like pour in. I’m hoping the installer just cemented in the bottom.

@Mo Lake is not the OP, he really should start his own thread on HIS issue.

 

[Mo Lake]

Cemented just at the top? Or the bottom? Or the whole thing?

Just the top on the terracotta flue. This isn't my actual pic but like this.

 

[bholler]

Just the top on the terracotta flue. This isn't my actual pic but like this.

View attachment 304133

You may end up. Breaking the top tile I don't know

 

[Mijoka]

Cemented just at the top? Or the bottom? Or the whole thing?

Good question. The internet is full of chimney sweeps remarking how eventually removing old liners installed with poured in cementitious insulation was a real problem . I could understand using the cementitious mixture for the first few inches at the bottom and perhaps the very top, but never understood why the rest would not just be poured in dry vermiculite or whatever you were using. It would probably make a mess when you removed it but could also be reusable. When the lifespan of a SS liner is said to be 15-30 years, one should expect to have to remove that liner some day.

 

[bholler]

Good question. The internet is full of chimney sweeps remarking how eventually removing old liners installed with poured in cementitious insulation was a real problem . I could understand using the cementitious mixture for the first few inches at the bottom and perhaps the very top, but never understood why the rest would not just be poured in dry vermiculite or whatever you were using. It would probably make a mess when you removed it but could also be reusable. When the lifespan of a SS liner is said to be 15-30 years, one should expect to have to remove that liner some day.

If it's dry it will just compress and settle to a rock hard lump at the bottom which is far worse to get a liner out of

 

[Mijoka]

If it's dry it will just compress and settle to a rock hard lump at the bottom which is far worse to get a liner out of

Then should we assume pour in insulation is simply an all around bad idea? Is it important to have some air flow inside a masonry flue even if a SS liner is installed to handle the heat and exhaust of the products of combustion? I wonder about moisture buildup during the months when the chimney sees no use.

 

[bholler]

Then should we assume pour in insulation is simply an all around bad idea? Is it important to have some air flow inside a masonry flue even if a SS liner is installed to handle the heat and exhaust of the products of combustion? I wonder about moisture buildup during the months when the chimney sees no use.

No. Pour in is not a bad idea at all in the right situation

 

[Mijoka]

If it's dry it will just compress and settle to a rock hard lump at the bottom which is far worse to get a liner out of

When you said dry, did you mean a dry mortar/vermiculite mixture getting hard or just vermiculite getting hard? Vermiculite did not strike me as something that would get compressed and hard unless perhaps it got saturated and then physically compressed.

 

[bholler]

When you said dry, did you mean a dry mortar/vermiculite mixture getting hard or just vermiculite getting hard? Vermiculite did not strike me as something that would get compressed and hard unless perhaps it got saturated and then physically compressed.

Yes just dry vermiculite will get compressed and hard at the bottom due the the thousands of expansion and contraction cycles. That is why it's no longer an acceptable chimney insulation

 

[Mijoka]

Yes just dry vermiculite will get compressed and hard at the bottom due the the thousands of expansion and contraction cycles. That is why it's no longer an acceptable chimney insulation

Was it ever resolved if the liner in the original post was lined full length with pour-in insulation? I thought that just perhaps the gap had been stuffed with an insulation material and then mortared over. FWIW, I see a lot of online questions about sealing off around the top and bottom of chimney liners and disagreement about suitable insulating materials to do that. I thought this was interesting.

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