whats considered best slow heat stone?

[MR GUS]

..Sort of thing I should know really (but don't)
Wish to tile both inside the stove hearth & on the other side  in order to..

A. satisfy looks for the modern-(ish rooms)
B. Add to any form of slow heat release in both rooms (ie room fire backs onto)

How thick should it all be to make it vaguely useful, or should I simply vent the back of the new stove siting through the wall into another room?

C ..& tile it!

[Ivan]

I can't really answer - but I suspect most ceramic/stone materials all have similar conductivities and heat capacities. I do like the idea of heating the chimney stack/fire surround. Our woodstove vents directly into a 9" brick flue which was installed when the house was built at the beginning of the 60s. The flue itself acts wonderfully as a storage radiator, and will store heat for over 24hours - keeping the stairwell and two upstairs bedrooms nice and warm even in very cold weather.

One American website I visited many years ago described a newbuild fireback - it was brick front and back, and the middle was backfilled with several tons of sand to act as a heat store. In order to get the heat into the sand, the whole mass was riddled with steel rods attached to metal plates on the fireback surface (to capture the heat at the surface). The guy claimed it would heat up in a matter of a few hours, and release it's heat over a few days. I've no way of verifying it's accuracy, but it sounds like a good idea.

In my sister's house, we used slate floor tiles to build the hearth - looked nice. In mine, I used a few flagstones that had been in the garden for years and used 'brick slips' from Wickes to make it look like a tidy brick-lined recess (actually, the fireback was brick, but very shoddy, and not good enough to expose)

[MR GUS]

This is precisely why I ask seemingly inane questions & go so slow, (information springs forth at different rates) ...sometimes the tomorrow manyana attitude comes good, having bodged over winter we now find ourselves in the position to tidy the rear & sides up with tiles etc, the stove area is quite well recessed & high (around 5.8 feet high) so will be able to utilise that eco fan & drying area without problem (thinking enough wood storage to deal with nasty flu achey limbs for a few days without going out etc) .basic drying of "stuff" etc. we wish to insulate the void around the chimney, so I'm wondering what area you're safe to pop in glassfibre insulation / celotex in order to channel & deflect heat rather than have it going up through the wall void & escaping through partial filled cavity etc.. (should point out the chimney liner is terracotta)
the "short" outer wall adjacent to the fireplace is to be scraped back of it's plaster in order to have 150mm ? celotex covering it, in fact i'd go as far as to say just having this wall temporarily celotexed  (exposed) knocked the need to heat the room down by around 20 % (estimation)
What does concern me though is the required "air-brick" which i'm extremely loathe to cut out ever, having removed the door to the living room the draw has always been satisfacory for the previous nasty open fireplace, & outside noises are extremely unwelcome through said air brick,not to mention damp air.
I'd prefer to get it "tight" then maybe draw air through somehow without spoiling the created heat regardless of any legalities.
I guess though the larger the uninteruppted surface area of tile (ie without grouting lines) the better for surface absorbtion & deflection backed where appropriate with insulation?