From: Jim Buckley Sent: Tuesday, May 05, 2009 To: Vin Jannetty Vin, Thanks for the pictures, including the one of the first oven your built. I think the stone veneer over your oven cracked because there was no air space or compressible insulation between the stone and the oven liner to allow for thermal expansion. We have found that the liners do expand and contract and are likely to crack so, to keep the outer shell from cracking, you have to isolate it from the inner liner. If patching the cracks doesn't work I would remove the stone and then cover the oven core with mineral wool or even regular fiberglass insulation, then some metal lath and a coat of mortar or stucco. Finally, re-lay the stone so that it doesn't touch the inner liner including the oven entrance tunnel. All this may only be marginally successful since it is hard to seal the stonework so that no water gets in it. That's why many traditional ovens have roofs over them as in the pictures at http://www.rumford.com/oven/Italianoven.html and http://www.rumford.com/oven/Apolloni/Apolloni.html
Best,
|