This post brings into mind another issue. How heavy is the mass? Can it be built on regular flooring/subflooring? We also have a space that has a shallow crawlspace under it. Was wondering if the mass would be too heavy to put on a regular (old farmhouse) floor.
I was also wondering how many square feet the standard (I guess 8 inch?? I am new to this and trying to learn) rocket mass heater will heat? Will it heat a first floor well enough for the heat to travel upstairs to the seond floor? I am learning about these. Love the concept! Like the previous poster, I am wondering how to do this with what I have to work with. Thanks!!!
