Using ovalized heavy flex liners - any recommendations?

[DBoon]

I'm planning for a new wood stove install at a home I am renovating. The stove will exhaust through a flex pipe up a 28' masonry chimney. I'd prefer to use an interior smooth wall pipe and an ovalized flex pipe that will also be insulated.

The reason I want to go ovalized is that the masonry chimney is part of a rumford fireplace design with a narrow throat and I'd like to keep the throat as narrow as possible to ensure that it works well as a fireplace (just future good planning). I have a little latitude on how large the throat can be, but not a lot, and a 5" throat would be better than a 7" throat.

Does anyone have any recommendations on brands or products of ovalized heavy flex liners to use in this regard? I'd rather buy the liner once and do it right, and absolute best cost is not the primary consideration. Thanks in advance.

 

[begreen]

If the damper area is the only restriction I would open up that area and keep it round. At some point in the distant future if you want to revert to a fireplace then weld a patch in the damper plate and rebrick that area if a little removal was required.

 

[bholler]

If the damper area is the only restriction I would open up that area and keep it round. At some point in the distant future if you want to revert to a fireplace then weld a patch in the damper plate and rebrick that area if a little removal was required.

If it is a true rumford the masonry will narrow down allot to so it may not be as simple as cutting the damper frame in this case.

Does anyone have any recommendations on brands or products of ovalized heavy flex liners to use in this regard? I'd rather buy the liner once and do it right, and absolute best cost is not the primary consideration. Thanks in advance.

We always use olympia armor flex liners for wood and we have had no issues with them. But really a heavy flex from any reputable manufacturer will do fine.

 

[DBoon]

If the damper area is the only restriction I would open up that area and keep it round. At some point in the distant future if you want to revert to a fireplace then weld a patch in the damper plate and rebrick that area if a little removal was required.

Hi begreen, great idea, and certainly worth considering. The plans I have right now are for a 7" throat opening using a standard Superior Clay Rumford throat piece, which is really 2-1/2 to 3" too much. But if I can prepare it to be made smaller in the future, that is worth considering.

f it is a true rumford the masonry will narrow down allot to so it may not be as simple as cutting the damper frame in this case.

Hi bholler, the design is a Rumford but with an expanded throat. All the components will be from Superior Clay but with a throat that can be located where I want it to be, which would of course make the (future) fireplace draw not optimized.

but really a heavy flex from any reputable manufacturer will do fine.

What would be considered "heavy flex"? I see a lot of 316Ti which is 0.006" (single wall?), which seems to not be heavy flex. I see some others that are twice as thick with a smooth inside. So what I am not sure of is whether the 316Ti 0.006" thick is considered high quality, or whether I should be looking for something twice as thick and ovalized. Also, would the corrugated inside wall be better to reduce the draft on the 28' vertical pipe, or should I not be too worried about this?

 

[begreen]

If it is a true rumford the masonry will narrow down allot to so it may not be as simple as cutting the damper frame in this case.

Yes that is like the rumfords I have seen too. That is why I included some brick repair to restore.

DBoon, is this a new masonry fireplace? Is this a renovation project on a home for resale?

 

[bholler]

What would be considered "heavy flex"? I see a lot of 316Ti which is 0.006" (single wall?), which seems to not be heavy flex. I see some others that are twice as thick with a smooth inside. So what I am not sure of is whether the 316Ti 0.006" thick is considered high quality, or whether I should be looking for something twice as thick and ovalized. Also, would the corrugated inside wall be better to reduce the draft on the 28' vertical pipe, or should I not be too worried about this?

no .006" is light wall. It will work fine but heavy wall will be much more durable in the long run. What ever you do dont get the 2 ply smooth wall stuff it is absolute junk

 

[claydogg84]

I got my oval liner from Chimney Liner Depot and didn't have a problem. I'm not positive which exact liner I got, but I do know it was whichever was the top of the line then (3 years ago). It is extremely plyable stuff, which was definitely a pleasant surprise.

 

[DBoon]

Thanks for all of the replies/help.

DBoon, is this a new masonry fireplace?

Yes, this is brand new - the interior components are specified as Superior Clay Rumford pieces, and since I likely cannot use a 4" throat (normal Rumford design), I'm having the architect design in a different throat piece that allows for adjustment of throat size, but I want to keep the throat as close as possible to the standard 4" throat."

What ever you do dont get the 2 ply smooth wall stuff it is absolute junk

Is this an example of the 2 ply smooth wall stuff I should avoid? https://www.rockfordchimneysupply.com/smoothwall-flexible-custom-kits.php

I got my oval liner from Chimney Liner Depot and didn't have a problem. I'm not positive which exact liner I got, but I do know it was whichever was the top of the line then (3 years ago). It is extremely plyable stuff,

Hi claydogg84, I think this was the 316Ti 0.006" thick - there seem to be plenty of people selling this kind of ovalized liner, but I was hoping to get something heavier/thicker.

 

[begreen]

Just process thinking here, but as an alternative to building a new rumford fireplace that will need immediate modification for a retrofitted insert, maybe consider putting in a top grade zero clearance fireplace? This would make sense especially if the residence is to be sold in the next say 10 yrs.. It will heat better and cleaner and will add to the home's value.

 

[claydogg84]

Thanks for all of the replies/help.


Yes, this is brand new - the interior components are specified as Superior Clay Rumford pieces, and since I likely cannot use a 4" throat (normal Rumford design), I'm having the architect design in a different throat piece that allows for adjustment of throat size, but I want to keep the throat as close as possible to the standard 4" throat."


Is this an example of the 2 ply smooth wall stuff I should avoid? https://www.rockfordchimneysupply.com/smoothwall-flexible-custom-kits.php


Hi claydogg84, I think this was the 316Ti 0.006" thick - there seem to be plenty of people selling this kind of ovalized liner, but I was hoping to get something heavier/thicker.

Here's a description of the liner I got. It says 0.010"

https://www.hearth.com/talk/threads/flex-king-hd-medium-weight-chimney-liner-now-available.119352/

 

[bholler]

Is this an example of the 2 ply smooth wall stuff I should avoid? https://www.rockfordchimneysupply.com/smoothwall-flexible-custom-kits.php

Yes that is the stuff

Here's a description of the liner I got. It says 0.010"

https://www.hearth.com/talk/threads/flex-king-hd-medium-weight-chimney-liner-now-available.119352/

Yes that is very similar to the stuff from olympia that we use. Olymia's is a little bit thicker and copperfeilds is a little thicker than that but any heavywall will be more durable than light wall.

 

[DBoon]

Hi bholler and claydogg84, thanks for your answers. I see that Olympia has the heavy flex in round and ovalized, so I'm covered no matter which way I go. I'm still not totally set on the Rumford fireplace - we'll see how the room layout works with that...if I go with a standard fireplace, it gets less challenging with the throat size.

I am assuming that all I need is the 304L grade, correct?

Just process thinking here, but as an alternative to building a new rumford fireplace that will need immediate modification for a retrofitted insert, maybe consider putting in a top grade zero clearance fireplace? This would make sense especially if the residence is to be sold in the next say 10 yrs.. It will heat better and cleaner and will add to the home's value.

Hi Begreen - always good to think differently about things, and thanks for your help and ideas. I've learned a lot from your experience and posts through a few years of hearth.com. We are pretty set on a full masonry fireplace and have the funds to do it. We're going to find a way to thread the needle and make it work both ways - either as a fireplace or as a space for a wood stove. We have a Lopi Answer (nice little heater) that we might re-use in the new house, or we might go with something different (TBD). But we are planning for a few different alternatives so that we don't get boxed in to one choice only.

 

[bholler]

we'll see how the room layout works with that...if I go with a standard fireplace, it gets less challenging with the throat size.

why are you building an entire masonry fireplace just to drop a liner and put a stove in it? It is really a massive waste of money.You are easily talking 5 times the cost of a very nice stove install.

 

[DBoon]

why are you building an entire masonry fireplace just to drop a liner and put a stove in it? It is really a massive waste of money.You are easily talking 5 times the cost of a very nice stove install.

Yep, absolutely. And it will look great from the inside and the outside when it is done. Luckily, it's my money so no one else needs to worry about me wasting their money

 

[begreen]

Oh no, building new and putting a masonry fireplace on the exterior wall too? What would Count Rumford say?