Drop me a liner? Wood Stove in a Masonry Fireplace

[Mech]

Experts and sharpshooters,

I'm hoping to get some advice on installation of a stove (VC Intrepid 2) in a masonry fireplace. More specifically, I am interested in hearing about your experiences with running the stovepipe into the terra cotta section without use of a flex liner.

I had assumed id be installing a steel plate to seal off the chimney from the fireplace with an allowance for the 6 inch stovepipe to plumb into it, but I'm not finding any products made for this purpose. It seems that by and large, folks are installing the soft flexible liners from the stove all the way up to the top of the chimney. Often this seems to mean ovaling the liner at the damper.

Can someone sell me on why i shouldn't use my perfectly good flue with terra cotta liner to vent my stove?

 

[begreen]

What is the the tile liner ID? What is the chimney height?

1) The flue area shouldn't be a lot larger than the area of the 6" flue pipe, especially if the chimney is less than 16'. It will weaken draft
2) Normal stove pipe is not allowed, it must be stainless and you will need flex to get past the damper area. A short length of liner can be used with a block off plate but...
3) Crud is going to collect around the stub of pipe every time the chimney is cleaned unless the block off plate is removed when cleaning (which would be a pita)

So reduced draft, a dirtier chimney, and incomplete cleaning are what can be expected.

 

[Berl2169]

True story[emoji115]

Without the liner the stove really won’t function correctly. You won’t be able to shut the door and control with air controls and every time you open the door you will get some smoke in house. I just tried this a month ago.....trying to save some cash and didn’t pay off.


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[Mech]

Thank you both for your replies. The existing flue is 8x8 and approx 22’, so in terms of draft it would seem to me that running a short section of pipe past the damper wouldn’t be terribly disruptive in terms of draft.

regarding the difficulty in cleaning... That’s understandable. My local place charges an extra 40 bucks for this type of arrangement.

Do any of you have a recommended source or brand or kit for liners and associated hardware?

Thanks

 

[brenndatomu]

The existing flue is 8x8 and approx 22’

So over double the recommended size...28.26 sq in. on a round 6", 8 x 8 is 64 sq in...that WILL affect draft. (not in a good way) AND, square chimneys like to build creosote in the corners...and it can be harder to clean out.
Plus, the chimney pros say that 99% of masonry chimneys don't meet clearance to combustible codes anyway...or at least no way to verify if they do or not. For me, when the stove is running, I sleep better having the fire isolated to a nice insulated liner...

 

[Mech]

No disputes with your cross sectional area math. I am curious though what makes you say “recommended size” as 6 in dia. The manual for my stove very clearly states it recommends either 6 in round or 8x8 square.

 

[Berl2169]

Thank you both for your replies. The existing flue is 8x8 and approx 22’, so in terms of draft it would seem to me that running a short section of pipe past the damper wouldn’t be terribly disruptive in terms of draft.

regarding the difficulty in cleaning... That’s understandable. My local place charges an extra 40 bucks for this type of arrangement.

Do any of you have a recommended source or brand or kit for liners and associated hardware?

Thanks

I believe what you are referring to, is called a positive connection to existing flue. If all your dimensions fit the manufactures specs with this type of connection I would say it would probably work. However, if you’re already installing to first flue tile from stove, why not go another 15’ ish to the top and reap all the extra benefits a full liner will give you? Peace of mind and you could start cleaning liner yourself and save that money too. It takes maybe 15 minutes max and you can clean as often as you like to give you added peace.

I have interior chimney so I didn’t use insulated liner and all is good.


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[brenndatomu]

No disputes with your cross sectional area math. I am curious though what makes you say “recommended size” as 6 in dia. The manual for my stove very clearly states it recommends either 6 in round or 8x8 square.

Well, I guess I used that term as a generality...I have no familiarity with that particular stove. Almost all stoves have a 6" flue connector anymore, and recommend 6" round for a chimney.
It is really confusing that they would say you can use either/or...6" round and 8" square are going to be on the opposite ends of the performance spectrum with a modern stove...can't say 8" square won't work...but I can say 6" round will work better.

 

[Sailrmike]

I believe the type of connection that the op is referring to is called "direct connect" or slammer install. Very popular in the'70s-'80s, in fact a previous home of mine (c.1986) had a Dutchwest installed this way. A huge pain to clean the system properly, and the house usually had a faint to strong woodsmoke odor. We installed a new insert with liner around 2010 and noticed a huge improvement in overall draft, and much less smoke odor.

 

[brenndatomu]

I don't think slammer installs are even legal anymore...and most assuredly a bad idea at the least!

 

[KC Matt]

I finished my install a month or two ago in a similar application and learned quite a bit the hard way. First, I got the kit from Rockford Chimney Supply and had excellent customer service. My install is in the basement and it took a 25' kit to reach the top of the chimney. You would be well advised to take advantage of their free tool rental and get the liner puller. I didn't and it was a bear getting the liner past the little jag in the chimney. I also had to get the 30* elbow to make a good connection.

Plan on cutting your original damper out and it's a nasty job.

You would also be wise to install rockwool insulation around the insert.

I would not attempt to use a modern insert without a liner and insulated would be best though I didn't insulate mine. No more than my insert will be used I cant justify the expense and my chimney is all masonry and is outside the house.

 

[begreen]

I believe the type of connection that the op is referring to is called "direct connect" or slammer install. Very popular in the'70s-'80s, in fact a previous home of mine (c.1986) had a Dutchwest installed this way. A huge pain to clean the system properly, and the house usually had a faint to strong woodsmoke odor. We installed a new insert with liner around 2010 and noticed a huge improvement in overall draft, and much less smoke odor.

This is not a slammer. That term only applies to inserts where the sealing is done at the surround. They are no longer legal. Berl2169 has it correct. The OP is asking about a positive connection. This is covered in the stove's manual.

 

[bholler]

The problem with direct connects is that all the instructions i have seen call for a positive connection to the flue tile. I have never seen one that was attached or any way to attach it.

Just run the full insulated liner it works way better and is much safer.

And are you sure the clay is 8×8? That is very very uncommon to see on a fireplace.

 

[begreen]

And are you sure the clay is 8×8? That is very very uncommon to see on a fireplace.

I was thinking the same thing. I can't recall seeing a fireplace with that small a liner.

 

[bholler]

I was thinking the same thing. I can't recall seeing a fireplace with that small a liner.

I have seen a few but they are rare. And they never work

 

[Mech]

I reckon you folks have sold me. I'll give the newfangled soft liner a go.

 

[bholler]

I reckon you folks have sold me. I'll give the newfangled soft liner a go.

The "soft liners" have been around about 40 years now. And have proven them selves many times over. But are you sure your clay liners are 8x8? If they really are they may need removed to put in a proper insulated liner.