Thinking of a cast oven build but had a question regarding the strength of a Perlite insulation layer for the hearth. I am thinking I would 'pour' a 4" thick layer in a form on the 3.5" hearth slab. Then cast my oven on top of that. Is the perlite mixture strong enough to bear the weight of the oven?
My concerns stem from moisture entering into the hearth slab and getting trapped under the insulation layer. Then add the freeze / thaw cycle of winters here in the northern states. My current design has a recessed area in the concrete slab for the perlite (p-crete). This would create a 'pool' for water to collect. Weep holes may work as far as helping moisture escape during the heating of the oven but I am not sure it will help with freezing conditions.
I should clarify that I was going to build an exposed dome oven (stucco finish no enclosure). The estimated weight of the dome is 1464 lbs. I estimate that the surface contact area bearing the weight to be 456 Sq In. so around 3.2 psi
My concerns stem from moisture entering into the hearth slab and getting trapped under the insulation layer. Then add the freeze / thaw cycle of winters here in the northern states. My current design has a recessed area in the concrete slab for the perlite (p-crete). This would create a 'pool' for water to collect. Weep holes may work as far as helping moisture escape during the heating of the oven but I am not sure it will help with freezing conditions.
I should clarify that I was going to build an exposed dome oven (stucco finish no enclosure). The estimated weight of the dome is 1464 lbs. I estimate that the surface contact area bearing the weight to be 456 Sq In. so around 3.2 psi
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