I'm trying to plan out a rocket mass heater for my house. My house is two stories with a basement. I've seen people using a perlite cob mix for the insulation layer beneath the rocket mass heater. Can I use the perlite cob for the bench of my rocket mass heater assuming that it isn't used as an actual bench. I know that the perlite does not have enough compression strength for that. What I really am trying to do is lighten the load on my wood floors. I'm still planning on Shoring the structure up. Any help and input would be great. I just want to make it as light as possible to reduce the stress from the heavy load.
