Brick walker rmh?

Hiya permies,

Our new house is being built in stages due to finances, trying to cash flow is as much as possible. My question is on building a RMH, and thinking to go with a walker 6” brick bell system.

Details: house is 40’x44’, single story on an insulated slab. Have pex in the floor for radiant heat but not sure if we’ll be able to afford getting the boiler installed this year. Walls are 8” concrete with 2” of insulation both inside and out (ICF), so should be very efficient. In the living room we have a chimney with triple wall pipe going up through the roof, 6-7” I.D., that’s what the Amish generally install around here (northern Missouri)

Planning to build a 6” j tube from bricks, walker style bell, insulated fiber board for the core with firebrick splits for the wood touching surfaces. Thoughts? Especially on what to use to cap the bells? Wife wants rustic style so I figured brick may be the easiest to build. I’ve played with a few different RMHs at Wheaton Labs but none with a bell that I recall.

Hoping if I can get one working well and using just a bit of wood each winter, maybe I can help encourage others in my area to build one too. My Amish friend uses 8-10 wagon loads of wood each winter!

A 6” J tube will need feeding very regularly, why not build a Walker core as well?

Maybe my terminology is incorrect… I did go ahead and buy the 6” core from the walkerstove site. Is that what you meant? Mainly fiberboard and adding several splits in the feed area?

Also, the chimney is about 2-2.5’ taller than the roof and exits at the peak. Roof is metal and 6/12 pitch, no trees of equal height within 100-150’ of the house, maybe a bit further…

Ah ok that is not what I meant but as you have already bought  a core that is fine ha ha.

Matt Walker has developed has own design core with a door and it is capable of loading batches of wood rather than feeding a J tube.

However in your case with an insulated house it wont require to much effort to get it up to temperature.
You chimney sounds fine, for a 6”  J tube you need a minimum chimney size of 6” but a 7” will also work fine.
In fact I think Matts J tube is 5.5” system size.

Leif Ing wrote:
Planning to build a 6” j tube from bricks, walker style bell, insulated fiber board for the core with firebrick splits for the wood touching surfaces. Thoughts? Especially on what to use to cap the bells? Wife wants rustic style so I figured brick may be the easiest to build. I’ve played with a few different RMHs at Wheaton Labs but none with a bell that I recall.

There's a section about bells at the batchrocket site, both theory and sizing. Keep in mind that a given batchrocket is twice as powerful as a J-tube of the same size, running in the same time frame. So a 6" j-tube can be compared with a 4" batchrocket for to calculate the Internal Surface Area of a bell.
In the Application section of the same site there are examples of how to cap a bell. Have a look at the video that goes with the Mallorca build.

Thanks Fox and Peter. Other than the core I haven’t set anything in stone (or brick) yet. I will go check the  site on batch rockets and bell sizing. My thoughts on brick were for aesthetics for her and hopefully ease of installation for me.

Will keep reading for now since we can’t move in yet… as long as we’re in before winter really hits!