Use Class A pipe to line masonry chimney - because it is CHEAPER than insulated rigid liner ??!

[N.E.K. - D.D.S.]

I have an old house from approximately year 1850. The main brick portion of this house has a large living room with two fireplaces (one on each end of the room).

The small fireplace in that room was ruined by a clown (certified chimney guy) as detailed in my previous post. I salvaged the situation by getting a small Jotul 3 TDIC-2 stove. It is really insufficient in the cold winter... but I think I will really appreciate it in the shoulder seasons. It is functioning as a supplemental heat source currently and working well.

The opposite end of this room has a large old Rumford fireplace in a completely unlined large old masonry chimney. It is obviously not to modern code, but seems to have quite good draft, and I have been tempted to fire it up, but for the fact that it is really covered in debris. I had wanted to have it lined with cement in order to preserve the original size and anatomy of it (it is a good design)... however it is difficult to find competent people to perform this work and at a fair price and to actually come out and do it.

If there ever were ANY fireplace to keep with the expectation of getting at least some amount of heat from it and not only ambiance, this would be it. That being said, I have acquired an old Woodstock Fireview “Belly Baffle”, which Woodstock has informed me is an obscure early model made only briefly. I have ordered the complete baffle kit which will essentially convert it into a Fireview 201 model. My expectation is that this will give a large amount of slow prolonged heat, as opposed to the small amount of quick and very radiant heat that I am getting from the Jotul.

This old unlined chimney is adjacent to brick walls of house on one side, and plaster directly on it on the interior. So I was again really tempted to just put some black stove pipe up the length of it and run it for now. It is accessible, and no problem for me to constantly inspect it and replace as needed. Of course, I read the hearth.com threads on that issue, and I know it “should” (for unclear definitive reasons other than longevity / corrosion resistance) have a proper liner so I was planning to buy rigid stainless steel liner.

Then of course, I am down the rabbit hole of “do I really need to insulate it”, and while I do think it would “work” fine without it, it seems that performance can only be increased by insulating it.

Due to the way I am installing it (from bottom up through the fireplace), it will be in 3 foot sections. I have not found good information on preferred method of insulating rigid liner. The rolls of insulation, glue, tape and netting that seem so appropriate for a flex liner seem to be thoroughly inconvenient for rigid liner. Especially since it has to install 3 feet at a time. I am estimating 18 feet total liner.

There is snap together rigid liner insulation (steel layer with pre-attached insulation) costing $33 for two foot sections. Three foot sections of rigid liner cost $67. So total will be (33 x 9) + (67 x 6) = $699 total.

Meanwhile I see Selkirk Sure-Temp double wall class A chimney pipe that would cost only $678 for the same total length. It is stainless steel on both layers and looks really nice. It can stand alone, and what a shame/waste to put it inside a chimney. I am going from completely insufficient in the eyes of hearth.com (uninsulated black pipe) to complete overkill (Class A bestos pipe). But as you see, it is roughly the same price, and even a few dollars cheaper.


- Is there any reason not to put the class A chimney pipe in??

- Is there some more reasonably priced alternative for insulation on rigid chimney liner??



Thank you very much for input on this matter.

 

[bholler]

I have an old house from approximately year 1850. The main brick portion of this house has a large living room with two fireplaces (one on each end of the room).

The small fireplace in that room was ruined by a clown (certified chimney guy) as detailed in my previous post. I salvaged the situation by getting a small Jotul 3 TDIC-2 stove. It is really insufficient in the cold winter... but I think I will really appreciate it in the shoulder seasons. It is functioning as a supplemental heat source currently and working well.

The opposite end of this room has a large old Rumford fireplace in a completely unlined large old masonry chimney. It is obviously not to modern code, but seems to have quite good draft, and I have been tempted to fire it up, but for the fact that it is really covered in debris. I had wanted to have it lined with cement in order to preserve the original size and anatomy of it (it is a good design)... however it is difficult to find competent people to perform this work and at a fair price and to actually come out and do it.

If there ever were ANY fireplace to keep with the expectation of getting at least some amount of heat from it and not only ambiance, this would be it. That being said, I have acquired an old Woodstock Fireview “Belly Baffle”, which Woodstock has informed me is an obscure early model made only briefly. I have ordered the complete baffle kit which will essentially convert it into a Fireview 201 model. My expectation is that this will give a large amount of slow prolonged heat, as opposed to the small amount of quick and very radiant heat that I am getting from the Jotul.

This old unlined chimney is adjacent to brick walls of house on one side, and plaster directly on it on the interior. So I was again really tempted to just put some black stove pipe up the length of it and run it for now. It is accessible, and no problem for me to constantly inspect it and replace as needed. Of course, I read the hearth.com threads on that issue, and I know it “should” (for unclear definitive reasons other than longevity / corrosion resistance) have a proper liner so I was planning to buy rigid stainless steel liner.

Then of course, I am down the rabbit hole of “do I really need to insulate it”, and while I do think it would “work” fine without it, it seems that performance can only be increased by insulating it.

Due to the way I am installing it (from bottom up through the fireplace), it will be in 3 foot sections. I have not found good information on preferred method of insulating rigid liner. The rolls of insulation, glue, tape and netting that seem so appropriate for a flex liner seem to be thoroughly inconvenient for rigid liner. Especially since it has to install 3 feet at a time. I am estimating 18 feet total liner.

There is snap together rigid liner insulation (steel layer with pre-attached insulation) costing $33 for two foot sections. Three foot sections of rigid liner cost $67. So total will be (33 x 9) + (67 x 6) = $699 total.

Meanwhile I see Selkirk Sure-Temp double wall class A chimney pipe that would cost only $678 for the same total length. It is stainless steel on both layers and looks really nice. It can stand alone, and what a shame/waste to put it inside a chimney. I am going from completely insufficient in the eyes of hearth.com (uninsulated black pipe) to complete overkill (Class A bestos pipe). But as you see, it is roughly the same price, and even a few dollars cheaper.


- Is there any reason not to put the class A chimney pipe in??

- Is there some more reasonably priced alternative for insulation on rigid chimney liner??



Thank you very much for input on this matter.

It isn't designed tested or approved for that situation. If you could figure out how to support it it would work but why not just use a quality flex liner?

 

[Trevor Tahclep]

It isn't designed tested or approved for that situation. If you could figure out how to support it it would work but why not just use a quality flex liner?

I was thinking the same thing.

 

[kennyp2339]

The class A pipe outer diameter is pretty large, I dont think it would fit into the existing chimney cavity, then theres also making a suitable mounting location for the weight of the pipe to rest on. Insulated flex liner is your friend here, install after thoroughly cleaning the existing chimney.

 

[N.E.K. - D.D.S.]

The chimney is VERY large (will need custom top plate) and was intended to vent the very large Rumford fireplace. I can fit 6" almost as is, and can fit 8" with moving just a couple bricks at the opening. I don't necessarily have a problem with the idea of a flex liner, but it is a straight shot up, and it was my understanding that a rigid liner drafts better and is easier to clean.

is there a good way to insulate rigid liners?

The class A pipe is meant to be used alone, and therefore I consider the chimney to merely be a chase at that point, and not really relevant. But yes, I see the big issue would be with supporting it. Top and bottom is no problem, but mid way is difficult . There is an old plugged up hole from a wood stove (which now happens to conveniently be in a closet) half way up the chimney that I could access it through.

Is the rigid liner and associated insulation much less heavy than the class A pipe?

 

[N.E.K. - D.D.S.]

The chimney is VERY large (will need custom top plate) and was intended to vent the very large Rumford fireplace. I can fit 6" almost as is, and can fit 8" with moving just a couple bricks at the opening. I don't necessarily have a problem with the idea of a flex liner, but it is a straight shot up, and it was my understanding that a rigid liner drafts better and is easier to clean.

is there a good way to insulate rigid liners?

The class A pipe is meant to be used alone, and therefore I consider the chimney to merely be a chase at that point, and not really relevant. But yes, I see the big issue would be with supporting it. Top and bottom is no problem, but mid way is difficult . There is an old plugged up hole from a wood stove (which now happens to conveniently be in a closet) half way up the chimney that I could access it through.

Is the rigid liner and associated insulation much less heavy than the class A pipe?

By the way, the fireplace is 38" high and 44" wide.
I am attaching some photos.

The Woodstock Fireview gives you some idea of scale. It still needs to be fixed up and painted, but I found the soapstone to be especially beautiful on this one.

The hearth was again terrible, with bricks just placed in there, with some sort of adhesive dispensed from a caulk gun, slopped on there, not level at all, and painted. I have removed the bricks, turned them over, cleaned them up, and gotten them into a much more reasonable position. I still need to actually cement the hearth together.

It is killing me putting a liner in this chimney at all. The really old retired brick mason (third generation) that I had visit here when I got the house, went on and on about how good the old masonry was, and that they are such good designs and highly functional... far superior to modern fireplaces and chimneys.

I suppose I am looking for some reassurance that putting a stove here is better than just using the fireplace.

I am a bit surprised at the recommendation to use flex liner here. It is what I originally assumed I would use, but I was advised that a rigid liner will function better and be more durable, and obviously a straight up run in such a large chimney would make it easy to install. I estimate 18 feet total length of liner, and 3 foot sections.

And as far as the original question of the post... would it be fair to say that the rigid liner is simply supported at the top of the chimney and at the bottom near the stove? And that it is lighter weight? I am still trying to figure out what would make the class A pipe any different, and I can only assume that it may be heavier and require support along its length.

Normally this is never even considered due to cost. But I think am either getting an overly high price on rigid liner, or an unusually low price on double wall insulated pipe.

 

[bholler]

By the way, the fireplace is 38" high and 44" wide.
I am attaching some photos.

The Woodstock Fireview gives you some idea of scale. It still needs to be fixed up and painted, but I found the soapstone to be especially beautiful on this one.

The hearth was again terrible, with bricks just placed in there, with some sort of adhesive dispensed from a caulk gun, slopped on there, not level at all, and painted. I have removed the bricks, turned them over, cleaned them up, and gotten them into a much more reasonable position. I still need to actually cement the hearth together.

It is killing me putting a liner in this chimney at all. The really old retired brick mason (third generation) that I had visit here when I got the house, went on and on about how good the old masonry was, and that they are such good designs and highly functional... far superior to modern fireplaces and chimneys.

I suppose I am looking for some reassurance that putting a stove here is better than just using the fireplace.

I am a bit surprised at the recommendation to use flex liner here. It is what I originally assumed I would use, but I was advised that a rigid liner will function better and be more durable, and obviously a straight up run in such a large chimney would make it easy to install. I estimate 18 feet total length of liner, and 3 foot sections.

And as far as the original question of the post... would it be fair to say that the rigid liner is simply supported at the top of the chimney and at the bottom near the stove? And that it is lighter weight? I am still trying to figure out what would make the class A pipe any different, and I can only assume that it may be heavier and require support along its length.

Normally this is never even considered due to cost. But I think am either getting an overly high price on rigid liner, or an unusually low price on double wall insulated pipe.

View attachment 289724

Ok your old mason may like the fireplace but he doesn't know what he is talking about quite honestly.

Liners are generally simply hung from the top of the chimney and yes liners weigh much less than a chimney. I would say about 1/4 the weight. And no flexible liners are not harder to clean at all.

If you actually want to add BTUs to your house yes putting a stove in there is far better. Even the best open fireplaces might hit 10% efficency which that fireplace isn't one of the best. Modern stoves installed and used correctly are pretty much all over 70% with some getting to 80%

 

[N.E.K. - D.D.S.]

Ok your old mason may like the fireplace but he doesn't know what he is talking about quite honestly.

Liners are generally simply hung from the top of the chimney and yes liners weigh much less than a chimney. I would say about 1/4 the weight. And no flexible liners are not harder to clean at all.

If you actually want to add BTUs to your house yes putting a stove in there is far better. Even the best open fireplaces might hit 10% efficency which that fireplace isn't one of the best. Modern stoves installed and used correctly are pretty much all over 70% with some getting to 80%

- I already have the stove.

- Okay, if the class A chimney pipe is heavier than rigid liner with insulation, and it has support requirements, then that is inconvenient.

- I understand that flex may be often preferred (or be the only option) in some cases due to easier installation.

- In my case, due to the huge chimney and wide access to it, I can easily install either flex or rigid liner with no problem. Either will drop right in (or be able to be pushed up).

If insulated flex liner is significantly cheaper I am fine with that.
If insulated rigid liner is significantly better, I am fine with that.

 

[bholler]

- I already have the stove.

- Okay, if the class A chimney pipe is heavier than rigid liner with insulation, and it has support requirements, then that is inconvenient.

- I understand that flex may be often preferred (or be the only option) in some cases due to easier installation.

- In my case, due to the huge chimney and wide access to it, I can easily install either flex or rigid liner with no problem. Either will drop right in (or be able to be pushed up).

If insulated flex liner is significantly cheaper I am fine with that.
If insulated rigid liner is significantly better, I am fine with that.

Good heavy wall flex liner is not cheaper at all but I really think it is more durable than rigid

 

[kennyp2339]

Extend your hearth in front of the woodstock and keep the highly radiant stove on the outside envelope of the fireplace so it works properly.

 

[bholler]

Normally this is never even considered due to cost. But I think am either getting an overly high price on rigid liner, or an unusually low price on double wall insulated pipe.

Both prices actually seem extremely low. My cost as a pro is close to double that for the stuff I use.

 

[gthomas785]

Look for heavy wall stainless flex liner, I think that is what you want. They don't tear like the cheap light wall ones and are smooth on the inside so it's easier to clean and drafts just fine. It's flexible but not too flexible. Chimney pipe would be too heavy and impossible to mount securely.

Edit: looks like this

 

[N.E.K. - D.D.S.]

Thanks for the replies and guidance.

The stove is just sitting in that position temporarily on the dolly. There is a good amount of room to push it in more, and still have enough clearance. I also have metal and ceramic spacers for a heat shield under the mantle and on the trim. The required area for thermal protection on the bottom (hearth) will be good, and those bricks go all the way down to earth floor in the basement.

Yes, I did think about a hearth pad in front for ember protection.... but it is a side loading stove. So I wondered if it might not be necessary?

Okay, I will see about pricing on Duraliner rigid preinsulated liner, or else heavy wall flex like in the photo.

The original question about why not to put class A in there seems to be settled.

 

[ctyankee]

There is a good amount of room to push it in more

You don't want to do that as that sends more heat up chimney/ into the brick. A foot back would be probably same difference. I'd plan on an ember pad in front even with side loading.