wow my build is starting to come along and i need to start thinking about insulation. my question is perlite or vermiculite??? can i use perlite and portland to insulate the dome and what is the ratio (sand,lime,cement and perlite) and for loose insulation is perlite ok as it is alot cheaper. or is vermiculite the way to go. oh and do i get a course bag and does anyone have ideas of where to get it in san diego thanks for all the help this forum is great!!!