I've never built or fired one, but I'd be a little concerned about it sitting bare on a wood floor. I'd at least put down some kind of thermal mass down before the rest went down, something that wouldn't get as hot as the rest of it, but like I said, I don't know. I'm new here. lol
Yes (although we cut the boards out and put the hearth onto the floor joists because we wanted the hearth flush with the floor). You just need to put in a heatproof insulating hearth. There will be code requirements around that (materials, thickness, how far the hearth extends around the stove footprint etc), so best bet is to get advice from your local authorities. It's not technically difficult though.
Location: Sunizona, Az
posted 8 years ago
im just learning about this but my question should have been what should i put down on the wood floor first and how thick?
I'm planning to install a box-type (but smaller due to limited space) than Pauls in an older house with a very low foundation, with little crawl space. Estimating the weight of the thermal mass is hard in a 4' x 6' x 2' area, (still undecided as to cob or pea gravel) but I believe I can reinforce my floor joists with a couple of shimed railroad ties, & then overlay the floor with a 3/4" plywood sheet, which should help distribute the weight.
Rocket Mass Heater Plans: Annex 6" L-shaped Bench by Ernie and Erica