cob drying time?

I have made a small batch of cob and wondering how long it takes to dry. Also, I plan on putting a cob hearth below and behind a wood stove. Can I go on top of wood floors if i use backer board? same question for sheetrock....I have been looking around for others who have done this but so far no luck, would love to hear any and all ideas!!

Backer board does not seem to have much of an advantage. Check your floor structure, make sure it is strong enough first. Plastic would be my choice, keep the moisture out of the framing/floor. This will need enough cob to protect the plastic from heat of course. The small greenhouse I am working on will have a 55 gallon drum cobbed onto the top of the woodstove - a copper coil will sit in the open vat, a pump will move the heat through pex into the soil. The drum boiler will keep the humidity adjusted in the greenhouse. Going to use the cob and some chimney tile around the drum to channel the flue gas around the barrel. Cob is a great material to use around woodstoves.

And drying time will not be an issue around a woodstove, normally it is a function of thickness and ambient humidity, you can use heat to dry.