nuthcuntrynut wrote:precast is how i do most all boilers and furnaces up here, just wanted advice on coal appliances, as this is my first.
i didn't know if it's open on the bottom and may need to be air tight? so blocks would leave small air space?
Its not open on the bottom anymore than a conventional boiler is, so don't worry about that... simply lay down some 2" thick precast solid flats
P/T ive never seen done (that cant be legal
), paint the concrete with dry lock to match your floor or boiler.