I am facing some similar concerns. I'm in SW Missouri, so not as severe of weather as the mountains.
I have to enclose a
concrete floor porch before I can build my RMH, because I do not want that much weight on the wooden floor over the basement. But if you can throw tons of weight on your floor, you are good to go in that regard. And *if* you are going to also put in an adobe floor, there is nothing at all lost by tossing all that clay and sand on your existing floor (to become a sub-floor).
These are the kinds of details that are unique to each situation.
However, here is another thought, and it is what I'm doing because there is no way I can put in a RMH right now. Plus, I like the idea of testing a J-style
rocket stove before building my RMH.
Right now I'm testing a dry stack J-style
rocket stove outside. I'm at the point of prepping the barrel to place over it so I can take those test measurements (temperatures are my concern, for fire safety mitigation). Once I am happy with this, I am going to set up the rocket stove/barrel inside, and run that as my wood burning "barrel stove" but fed by a j-rocket for the "engine."
If your floor can take the weight right now, you can also stack up brick, block, rocks, etc around the stove and exhaust this winter, as you accumulate these materials. That'll give you some thermal mass. You can do this with either a standard wood burning stove or a j-rocket barrel stove.
I don't know if this is a better idea, but it is another idea
? It's averaging at or below zero this week in the mountains of montana. Stick that regular wood burner in and get it smoking , then build your RMH. As glenn said getting and working with clay at low temps would be almost impossible, it can be done, you'd need to get it indoors and warm . The same 8" roof jack that you use for your regular wood stove can be used for your rmh when its ready to go thru the roof. If it were me I would push the kerosene heater aside and use the smoking dragon of a regular wood stove while I acquired all the pieces and parts to build my RMH. By the way ... do you have a copy of ianto evans book "rocket mass heaters " ? if not then you should get one and read up this winter snuggled to your old wood stove and dream of next winter, of laying on your mass watching the snow fall...
