Chimney Liner Sizing, 20 foot tall masonry chimney

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mnowaczyk

Feeling the Heat
Feb 19, 2009
279
Delaware
01EF7E1B-FCC2-4812-AA27-8907EE977F9A.jpeg

I’m looking to buy and install chimney liner, probably myself on a ~20 foot tall chimney. It’s hard to see the top in these two pics, and I see that I could possibly need to extend the chimney and/or install a different type of roofing that can’t burn like that asphalt might.

Anyway, this is the detached garage with a chimney that has about a 6” diameter hole in the side around 6 feet high. The garage also has a wall hung radiator next to this. I will probably install a high efficiency natural gas heater and want to out in a wood stove or just use one of the two identical Vermont Stove company 1981-82 Shelburne fireplace insert models I already have. It’s nice to have spare parts. That model specifies an 8” liner, and I currently get the best fires in my 40 foot 13x13” terra cotta lined chimney with really hot fires. That makes sense since there’s so much chimney to heat.

Anyway, I don’t know the BTUs of my inserts, but figure I should be able to estimate it or size the liner for a wood believing stove and maybe get one of those instead of making a fireplace around this insert.

My gut says that smaller diameter will draft better whereas wider diameters might act more like a hole in the wall that can downdraft.

I see this sizing chart, and am still trying to make sense of it and figure out what the best draft might be.


I will see if I can get a shot of the hole in the chimney and better shots of the back side of the chimney too. I’m not living in this house, so it’s a little harder than normal.
71D03CCF-A628-4818-BD76-FB5DECC0A896.jpeg
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,474
central pa
View attachment 292187 I’m looking to buy and install chimney liner, probably myself on a ~20 foot tall chimney. It’s hard to see the top in these two pics, and I see that I could possibly need to extend the chimney and/or install a different type of roofing that can’t burn like that asphalt might.

Anyway, this is the detached garage with a chimney that has about a 6” diameter hole in the side around 6 feet high. The garage also has a wall hung radiator next to this. I will probably install a high efficiency natural gas heater and want to out in a wood stove or just use one of the two identical Vermont Stove company 1981-82 Shelburne fireplace insert models I already have. It’s nice to have spare parts. That model specifies an 8” liner, and I currently get the best fires in my 40 foot 13x13” terra cotta lined chimney with really hot fires. That makes sense since there’s so much chimney to heat.

Anyway, I don’t know the BTUs of my inserts, but figure I should be able to estimate it or size the liner for a wood believing stove and maybe get one of those instead of making a fireplace around this insert.

My gut says that smaller diameter will draft better whereas wider diameters might act more like a hole in the wall that can downdraft.

I see this sizing chart, and am still trying to make sense of it and figure out what the best draft might be.


I will see if I can get a shot of the hole in the chimney and better shots of the back side of the chimney too. I’m not living in this house, so it’s a little harder than normal. View attachment 292188
The liner should match the outlet size of your stove.
 

mnowaczyk

Feeling the Heat
Feb 19, 2009
279
Delaware
I will have to see if I can find that manual that I scanned and posted here many years ago. I left it on the bookshelf next to the insert, and my wife apparently didn’t like it there. So now it’s MIA.

I will probably table this until I learn what size liner I can actually fit in the chimney.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,474
central pa
I will have to see if I can find that manual that I scanned and posted here many years ago. I left it on the bookshelf next to the insert, and my wife apparently didn’t like it there. So now it’s MIA.

I will probably table this until I learn what size liner I can actually fit in the chimney.
What size is the outlet on the insert?
 

mnowaczyk

Feeling the Heat
Feb 19, 2009
279
Delaware
What size is the outlet on the insert?

The currently owned extra insert is effectively 8” I believe, but it is rectangular. I’m not married to the insert either, but having two of them, it’s nicer to perhaps use this instead of trying to store it. It’s sort of double-duty as parts and something that could be used if in the garage in this way.

I checked the garage chimney from below today, and the hole at the bottom is currently 6” round, and the inside of the chimney at that location is apparently not lined and looks like it might fit an 8” if needed, just a bit more bashing at the hole in the side to do 8” I’m afraid.