Lining Terra Cotta Chimney?

[NVHunter]

Ok,

Things have changed for me a lot. So we moved and bought a house a week ago and I'm already looking at wanting a wood stove installed.

The house was built in 1972 and has a double masonry chimney on the exterior of the house. The larger Terra cotta lined chimney services the upstairs fireplace while the smaller chimney goes down to the daylight basement where there was an "Earth Stove" installed years ago.

During the home inspections the chimney sweep stated the smaller Terra cotta chimney was an 8x13" flue. They also said the chimnies needed cleaning and some sealing.

These repairs were stated to be completed as part of the purchase agreement. After we bought the house I looked at the smaller chimney today and it definitely was not cleaned. Has old soot and cresote in it and no evidence of cleaning what so ever... Ok enough nagging.

My question is, I want to install an Ideal Steel Hybrid in the basement utilizing the small chimney. While looking at it today I measured it and it looked like the inside diameter is 7" x 12".

Seeing what the chimney looked like I want to install a SS liner down the chimney. Is there going to be room to install a 6" liner down this setup?

I want it to be insulated, is this going to be possible?

If not Ive heard of people breaking out the Terra cotta tiles to fit insulated liners. Is this an option too?

Here are a few pictures of the location they took the thimble out of the wall and where the chimney starts.

 

[bholler]

I want it to be insulated, is this going to be possible?

Yes but not without some work the liner will either need to be ovalized or the old tiles will need broken out. And you should check with the manufacturer but typically when we ovalize we go up to a 7" liner to maintain proper volume

 

[begreen]

If it's a straight shot down, 6" DuraLiner is pre-insulated and should fit.

 

[NVHunter]

If it's a straight shot down, 6" DuraLiner is pre-insulated and should fit.

Nope, looks like there's a 45 straight from the thimble location.

What happens if they break out the Terra cotta? Does the insulated liner then just go in its place?

 

[begreen]

Yes.

 

[gyrfalcon]

Nope, looks like there's a 45 straight from the thimble location.

What happens if they break out the Terra cotta? Does the insulated liner then just go in its place?

Yes. I put in a new SS chimney for my stove, but the terra cotta liner in the chimney the oil boiler uses was cracked, and on the advice of my sweep/installer, I had it taken out and replaced with a SS liner. Can't remember what it cost to do that, but maybe 800 bucks? No idea whether it makes sense to just put a new liner inside an existing intact terra cotta or not.

 

[bholler]

No idea whether it makes sense to just put a new liner inside an existing intact terra cotta or not.

If you can fit one with proper insulation and you can get the old liners clean then yes go ahead and line inside the old tiles. Otherwise take out the old liners you need to have the liner insulated almost all the time

 

[NVHunter]

Ok,

New question. Looking at my chimney there are two flues in it. My house is 2 stories with a masonry fireplace on the top floor with a large straight flue. We don't plan on using this fireplace at all for anything.

The second flue is in the same chimney and runs from the daylight basement on the bottom floor of the house up and around the fireplace and then out the top of the chimney.

This is the smaller flue (7"X11") and is for a wood stove that has a hole in the cinder block wall for a thimble in the basement.

I want to reline this flue for a wood stove install with an insulated stainless steel 6" liner. Almost all above are stating the terracotta liner will have to be removed for a proper insulated SS liner install.

My question is, I belive my current flue for the wood stove "zig zags" around the fireplace with 2, 45s. Can a flexible SS go in its place once it's removed?

I've attached a photo I found online for a visual reference. The picture is for two fireplaces which is not the case for me. I'm just using it to show everyone what I think my chimney set up looks like and if it's possible to reline it with a insulated SS liner in the same manner for the basement flue only.

Thanks and sorry for be long winded...

Mike

 

[bholler]

I belive my current flue for the wood stove "zig zags" around the fireplace with 2, 45s. Can a flexible SS go in its place once it's removed?

Yes it can but in situations like yours some times the old clay cannot be removed safely. I cant say if yours can be or not without being there if the 2 flues are not properly separated you risk damaging the fireplace liner when you break out the other one. In that case i would go with an ovalized liner and still the chimney may need to be opened up at those offsets to get the liner through

 

[NVHunter]

Yes it can but in situations like yours some times the old clay cannot be removed safely. I cant say if yours can be or not without being there if the 2 flues are not properly separated you risk damaging the fireplace liner when you break out the other one. In that case i would go with an ovalized liner and still the chimney may need to be opened up at those offsets to get the liner through

Ok, what if I place an "un-insulated" 6" round liner inside the terracotta liner and then use a poured in style insulation around the new liner?

Would this achieve the same thing for me?

Thanks

Mike

 

[bholler]

Ok, what if I place an "un-insulated" 6" round liner inside the terracotta liner and then use a poured in style insulation around the new liner?
Would this achieve the same thing for me?

First off even a bare 6" liner will be very hard to get in through those offsets. And unless you have the required clearance from the outside of the chimney to any combustible material (!' for an exterior chimney and 2"for an internal one) pouring insulation in this situation would not meet code because there would be no way to get the required 1" of insulation. It would help you some with performance but would not meet code and for most liner manufacturers improperly insulating voids the ul listing as well.

 

[NVHunter]

Ok, sorry I'm picking your brain(s) so much but I've been emailing Woodstock and they've been extremely helpful but it's after hours and one more opinion I get here.

They stated I need to maintain 28 square inches of flue space for what ever liner I put in, (area of a 6" round flue is 28 square inches).

They gave me some oval shaped liner sizes that should work I think. Here's what they said about oval liners.

"If you go with an ovalized liner, you need to maintain a 28 sq.in. area,and your sizes could be:

5"x 8.15" - using a 6.5" liner
5.5" x 7.85" - using 6.5" liner
4.5"x 9.1"- using a 7" liner
5" x 8.75"- using a 7" liner"

Question, do you think when they said "using 6.5" liner above or using 7" liner above they're stating take a liner that size and ovalize it to those measurements?

Ok,

These are bare liner sizes without insulation so to put insulation on them I need to add 1"-1.5" of the diameter of liner correct.

So my thought were to use either the 5"x8.15" or 4.5"x9.1" oval liner and then add the insulation to give me a total diameter of 6.5"x9.65" or the other liner at 6"x 10.51" for my 7"X11" Terra cotta flue.

Also, looked closer at the offset angle tonight and it's more closer to 20 degrees than the 45 degrees that I thought earlier.

This should make it a little easier right...?

Does any of this sound correct to you guys.

I know ultimately I'm going to have a professional come out for the definite answer but I'm a guy who likes to research stuff first so I kind of know what to expect and know when it comes to talking to the professionals...

Thanks

Mike

​

 

[bholler]

That all sounds right to me And 20 degrees may be easier than 45 it all depends on how smoothly the offset was made. As far as 6.5 or 7 i personally have not seen 6.5 from any of the suppliers we use so i think you would be using 7". That is what we do when we ovalize for a 6" stove. Well we will typically break out the liners but like i said that is not always a good option.