Hopefully someone can answer this, I'm building a bread baking oven that will be in daily use(Sunday excepted), a cross-section of the hearth will be as follows: 4" firebrick.4" thermal concrete reinforced 8" vermiculite mortar. Is this enough insulation and secondly should the vermiculite mortar layer given its thickness also be reinforced with a rebar matrix.
Re: hearth slab
I can answer this question! Yes I think it is enough insulation under the hearth.
My build is a bit of a hybrid, but my hearth is similar:
115 mm of firebrick (about 4 1/2")
100mm (4") reinforced concrete (as a "floating" slab, so separated from the surrounding base structure)
150mm (6") Vermicrete insulation underneath.
A link to my build: http://www.fornobravo.com/forum/f21/...ula-20323.html (40" brick oven on Tasman Peninsula)
Admittedly I have only cooked in my oven twice, but on both occasions I had the internal temp up around 500C at the dome and under the Vermicrete it was mildly warm at best (OK to leave my hand there as long as I liked). My dome has no extra thermal mass but is well insulated, and the next day after firing the internal temp is still around 250C.
I didn't put any reinforcing through the Vermicrete layer, and it didn't need it. I put a few large screws between the vermicrete and concrete layers, and I also put a few short pieces of rebar (3-4") from the sides of the Vermicrete into the blocks of the stand before I core filled them. I was a bit worried about the weight of the Vermicrete layer being held by those crews only. I'm still not sure if this was overkill but it didn't hurt. I think to put rebar all the way through the Vermicrete might detract from its insulating properties?
Having said all that, I think there are probably better ways to insulate under the hearth slab. On my next build () I think I will investigate polystyrene blocks (eg Foamex) for under the concrete hearth slab. Surely these would be easier to fit and better insulators?
Hope that helps.
|Thread||Thread Starter||Forum||Replies||Last Post|
|cracking in hearth slab||camooch||Pompeii Oven Construction||2||03-26-2012 06:47 AM|
|2 x 4's inside the hearth slab||masuzzu||Tools, Tips and Techniques||1||10-19-2008 08:49 AM|
|Between Hearth SLAB and Hearth BRICKS, slip plane.||Marcel||Newbie Forum||2||09-12-2005 05:35 PM|
|How far to cantilever the Hearth Slab?||Marcel||Getting Started||2||08-31-2005 09:38 AM|
|Spanning the wood storage below the Hearth slab.||Marcel||Getting Started||0||08-22-2005 09:13 PM|
All times are GMT -7. The time now is 12:05 AM.
Search Engine Friendly URLs by vBSEO 3.6.0
© 2006/10 Forno Bravo, LLC