Straight run in cob or stratification bench?

    Here is my idea, presently I heat my barn with a catalytic wood stove with a single wall stove pipe running up 12 feet to an insulated pipe that passes through a loft and then out through a metal roof. I use my barn to work on my equipment so I need as much floor space as possible so what I am planning is to go about 15 feet along a concrete wall away from the woodstove and put my rocket stove in that location then run a straight pipe from there through a cob bench and then intersect with the woodstove chimney. I was also thinking of using Matt's idea of making it just a stratification bench, my objective is to not only heat the bench but also heat the mass of the NW concrete foundation wall because my barn is built into a small hill so is half below grade, any suggestions would be welcome, thanks, Chas.

Hi Chas; Welcome to Permies  and the wonderful world of rocket science!
Wanting to build your rmh is the first step down a one way trail … soon there will be no going back for you... you will become a rocket scientist ! OH NO...
Do you have a copy of the rmh builders guide ?  Readily available on Amazon. I highly recommend locating a copy. Best money you will spend!

Your idea of using the stem wall as a part of the mass is a good one... as long as that wall is insulated from the outside.
If it is not insulated then you would want to insulate your rmh FROM the concrete. Otherwise it will steal all your heat and move it outdoors.

As this is a shop rather than a residence , using Matts half barrel system would be my choice , it will give you more heat faster.  A cob/rock bench would take longer to heat but would stay warm longer.
Do you know which style and size of rmh you are wanting ?  Standard J tube in 8" ? 6"  or are you wanting a batch box style?

This is to replace your current stove correct ?  Not try to have a 2 stove system ?
I have attatched a photo of my new shop heater. It uses a barrel for instant heat AND a brick bell to store that heat. Works great and has a small footprint.
Here is a link to that thread, https://permies.com/t/94980/Brick-Bell-Shop-Heater


Keep us posted on your progress.
Ask all the questions you wish
Take plenty of photos!

Hi Thomas,
   First and foremost thank you for your information, I have that wall insulated and I do have the book in my hands and it is a great book. I used some salvaged insulation on the exterior of the concrete foundation any areas above grade going below grade as I remember about 2 to 3 feet down it is not insulated all the way down to the footings. Your set up looks to be what I will model mine after. Thanks so much, Chas.