Doctor Drivel wrote:

If you want thermal mass: cheaper dense concrete blocks can be used no more
than 4" thick, a layer of 6" or 7" of insulation and then thin brick slips
(very thin bricks of say 1" thick) to get the brick affect...

Or nail diagonal dark face boards to SIPs for an outdoor Tudor effect and
hang shiny water-filled platforms under a shiny ceiling for higher temp
thermal mass that stores 7 times more heat than room temp mass, with
better room temp control.

Nick