6 Rocket Builds - 3d Plans - Free Heat Bundle

Paul just released a new video comparing the temps of the inside air, outside air, rmh and pipe exiting house.  This is very compelling!

I think I'll be purchasing this soon!

I'm going to be building a mass bench for my Liberator soon, but it in the shop in going to build something homemade!

I would like to build the pebble rmh so would like to buy the book.
But... it looks like the plans need refractory bricks?
I don't have them, so can I fabricate flue pipes instead? As well, can I build this directly on a wooden floor using perlight clay mix as an isolator? I thought about using an aircrete slab underneath the perlight clay mix.
I would only use it for four months in the year.