michael Egan

I have a 40 x 60 pole barn. My plan is to section off about a quarter to a third of it and insulate to make a shop heated by my batch mass heater. that's 600 to 800 sq. ft. any ideas on how to insulate walls and a ceiling?

What a great project Yannick!
I looked at the pdf you linked to. a few questions:
Will you pour a concrete beam around the hole? what size, also what kind of steel reinforcement in the beam? Assuming you do, I would embed probably two pieces of rebar to reinforce it, make a ring. I would also put some steel pegs (could be little pieces of rebar, scraps, etc) into the top so they stick out and hold the roof when you pour it.
How high is your wall? The higher, the stronger it will need to be.

What about drains, cleanouts?

Art Ludwig has a really good book you might want to look at. If you apply ferrocement you might want to do a small project first, say, a thin slab or something creative. Ferrocement will last 100s of years if cured properly. Ludwig goes into much more detail in his book than the pdf you cited.

Best of luck to you! Keep posting.

and thank you for experimenting and sharing ideas/results. We all benefit. Keep going!

It seems to me that the burnt toast is carbon... biochar... charcoal. If I'm correct and not missing something then any carbon substance could be an ingredient in an insulative mix as long as oxygen is not present in high enough amounts to trigger combustion at certain temperatures. That's basically what people were doing when they experimented with using sawdust in an insulation mix: the sawdust pyrolized and apparently stayed stable in a honeycomb kind of configuration but was also fragile which wouldn't matter if it were in between the firebox and the outer masonry skin of a heater.

I don't have a science background; i'm a retired guidance counselor but have read a bit about the molecular components of materials mostly over the past 10 years of experimenting with and building mass heaters. My understanding is that plastic material is, at its core, petroleum, which is compressed fossils, hence the name, along with being called "hydrocarbons", molecules composed of hydrogen and carbon. What I don't understand is the difference in the length of the various molecules and how/if that affects burning/pollution: long chain hydrocarbons such as petroleum, for example, I think burn differently than short chain molecules.
PVC and many petroleum based combinations are probably really really bad. I would welcome more comments like the above to help us get informed. I have a huge  ("sad") sack of poly bags that I want to get rid of in the least bad way possible.

March is grass burning time in central Illinois and our rural neighborhood is often covered with a smoky haze. I wonder if burning certain waste plastics in my rmh is adding--- a lot, a little, or just CO2--- to our air.

ps. I haven't burned many bags--- yet. but the few I put in melted, then, when liquid, appeared to burn as clean as the wood with zero smoke. But I don't have testing instruments beyond my eyes and nose.

Plastic bags are pure polyethlyne, I think. Could they be burned in an efficient rmh as cleanly as wood?

Here are some pictures of the heater in the pole barn. a few specs:
8" flue
chimney is about 20' tall, black 8" stove pipe sits on an 8" elbow on floor of bell, then switches to 8" heating duct at about 8' (thinner gauge, galvanized), 12" heating duct starts at top of bell and sealed with cob to for a semi air tight insulating space like a double wall insulated chimney, total cost, around $200; temp at eye level is around 160F (uncomfortably warm to touch but doesn't burn)
T primer out of chimney for cold starts, works well;
bell is around 2.5'x 5'x3' tall, all single skin standard brick setting on 8'' blocks and perlite cob floor, top is bricks set on steel t posts, covered with screen and cob;
firebox is peter berg's 8" dimensions, standard firebrick except ceiling which is 1" ceramic fiberboard. I will redo this in the summer and make some refractory slabs to set on the ceiling to protect the soft fiberboard.
p channel is two 1.5" steel tubes with flaps on end to create turbulence;
riser is 4' tall, 8" diameter, octagon shape made of 1" ceramic fiberboard.
Almost no smoke if I start the fire right, takes about 5 minutes to rocket. The one picture of the chimney is steam on day 1. The single skin bell works great in my barn since it heats up faster and retains some heat to give off overnight but I would only need that to keep engines sortof warm on really cold nights.

Overall it's a real good heater. My thanks to Peter Berg and Matt Walker for sharing their work on the batch heaters!

I just finished an 8" batch box (Peter berg's specs) in my 40x56' uninsulated pole barn in central Illinois and am very happy with it- 2 stacked barrels for instant heat and one large bell, single skin brick. with your dimensions I would recommend an 8" batch box-- not a top feed. I switched to the batch box in 2011 with my 34x30' shop: the Ianto Evans type top feed just didn't allow enough btus to be burned and heat up that shop... I tried for over a year.

Regarding floor heating, other commenters pretty much covered the issues and I also would say that heating the floor is possible but would require isolating the mass so it doesn't bleed off heat and also figuring out a smaller floor area to heat: your pole barn would have way too much floor space to heat. as one person said, you only have a finite amount of heat to bleed off before your exhaust loses it's pumping capacity.

You might want to look at Peter Berg's shop batch heater which has 3 stacked barrels; if you start with 2 or even 3 you could later try taking the top barrel and running 50' of 1/2" copper around the top section inside the top barrel, screwed/bolted to the sides of the barrel. Then run an antifreeze solution powered by a small pump through a pex grid on maybe 200 sq.' of floor. Any liquid heat transfer system needs to be designed and built with safety features including pressure relief valves, no air pockets, etc. so if you've never done this I would get some help from someone who has. One advantage of adding the coil later is that you could start and see/feel how the stove performs and then modify it.

Regarding ducting, I no longer use ducting and instead have switched to bells/chambers. Bells are superior in every way, in my opinion. I would not recommend using ducts to bleed off heat into storage areas. Also, you will need to be careful about dropping your exhaust too low, especially in a duct as it will stall if you go below a certain level.

I'm checking out reviews on brad Lancasters latest book,he is definitely one of the best on water use. Jane your comment about trying to get your husband on the same page made me laugh, My wife is not so enamored with my fanatical permaculture plans and I keep thinking we should start a thread for partners of agnostics or something but that would probably get too complicated!