I've been given some tiles,concrete balcony tiles. I was wondering if they would be suitable for under a fire brick hearth. They are 22 mm thick,there's enough for 2 layers,if that's even possible ? There's lots of data I don't understand Dry density approx 1600 kg/m3 Flexiral strength 3 N/mm2
Most importantly the thermal conductivity is 0.79 W/mk I don't understand any of that to be honest,can any resident experts please advise me whether or not they would be suitable ?
weren't you planning to use thermalights and calsil board under your floor? or are you thinking of trying to use these instead? if you are, i wouldn't bother and would steer clear of those mate to be honest, i don't really understand the figures either but what you want under the floor is some decent insulation, its arguably the most important part of the oven to get right. you've got a few different options though on how you go about it, you could go for about 4" of vermicrete (vermiculite mixed with cement at around 5 or 6 to 1 for under the floor off the top of my head) or a lot of people go for thermalight blocks which are probably the easiest method or calsil board which i don't know a lot about sorry. if i were you i'd stick to your original plan!!
yea definitely! its the one part of the oven you need to get right first time as you can't change it after! if you wanted to cut the cost a little you could do away with the cal sil board and just use the thermalights?
Cheers for that. Would using cal sil and thermalights be over the top and wasteful,or is it more the merrier,as I suspect ? I imagined laying fire bricks on a cal sil board would give me a good surface to get them level.
G'day The excepted standard for insulation for the hearth seems to be 50 mm of cal sil or ceramic board. 100 mm of pearlite/cement will provide the same level of insulation. But thermalite block (ACB) i dont know of a standard. Ive got 50mm of Hebel brand ACB as hearth insulation. Im happy with the performance of my oven and it doesn't seem to differ from others that I read about. But I do find after 24 hrs the underside of the slab is slightly warm. So I suspect perhaps it should be 75 mm to 100 mm thick would be best Regards dave
All as above... this question is pretty well where I started last year, and though hell-bent on a design I'd established, I was gently persuaded that I should go for insulation as well as mass in the floor - I was able to incorporate a vermicrete layer with only minor adjustment to the plan.
Look at it this way - cos it's very real and ahead of you - imagine your first 'burns', the anticipation of those bakes... and through a bit of hastiness now, you can't maintain temperature. You can probably get more insulation over the dome, but retro-fitting the slab is a pain.