32" build in Calgary, AB - pompeii neapolitan

[UtahBeehiver]

Our goal is not to harp on the issue but to make you oven the best it can be. With all your hard work of planning and design, it will be a great oven. A 5 to 1 pecrete mix is suggested for under the floor and dome since this ratio has enough compression strength for supporting the dome and floor and adequate insulation value. Roughly 4" 5 to 1 pcrete equals 2" CaSi. So a total of 4" CaSi equivalent is a very good insulated floor.

[IH123]

I have almost everything I need to build the oven purchased and stored in dry basement over winter, I already purchased perlite, "Ceramic fibre blanket 2300°F 1'' 8LB/FT3 (1 Box 47.3sf)", and 5 count of "Ceramic fibre board 2300°F 2'' X 12'' X 36''" . I even have ThermoBond 915 100lbs refractory mortar purchased about a year ago placed in tight closed plastic pail never opened yet. The only thing I haven't got yet is either refractory castable or a steel plate for the doughnut base. so my design requires using ceramic fibre board under insulation not CaSi board

for weeping holes, I could even cut using my concrete saw shallow channels grid all over the slab; however unfortunately, at this moment, I am still not sure I need to do anything for making a "pooling water" drain from a hole because: I have a 6" thick slab placed mostly on grouted cmu block cores with very little gaps under it and still connected to a bottom slab that is 5.5" thick ... and got lots of fibre on slab. I can't imagine the oven can produce enough moisture to saturate close to 3 tons of concrete between firings . I most likely be a light user of the oven, may be fire it few times a year or so (not good to plan to design it so though). I have a feeling that weeping holes would be more suitable for large open span slabs with wood being stored under the oven that the slab would be bowed in centre creating a gap between the oven base and the slab where it will get filled with no emptiness but moist air. My priority in my oven is to have extremely rigid and stable foundation that will not propagate settlement to oven and water should not get on it. I still have close to a month to research it more and decide , for now just waiting for concrete to cure.

any help about my insulation stack design and if I should use castable refractory for dome wall support or instead use a 1/4" mild steel sheet one? as I am not using tiles under the dome walls, the ceramic fibre board and perlite if they creep or settle could cause settlement on a half brick and that if combined could cause a dome instability, so wanting to put a very solid doughnut under the dome walls ONLY while hearth can be on its own ...

[david s]

I have almost everything I need to build the oven purchased and stored in dry basement over winter, I already purchased perlite, "Ceramic fibre blanket 2300°F 1'' 8LB/FT3 (1 Box 47.3sf)", and 5 count of "Ceramic fibre board 2300°F 2'' X 12'' X 36''" . I even have ThermoBond 915 100lbs refractory mortar purchased about a year ago placed in tight closed plastic pail never opened yet. The only thing I haven't got yet is either refractory castable or a steel plate for the doughnut base. so my design requires using ceramic fibre board under insulation not CaSi board

for weeping holes, I could even cut using my concrete saw shallow channels grid all over the slab; however unfortunately, at this moment, I am still not sure I need to do anything for making a "pooling water" drain from a hole because: I have a 6" thick slab placed mostly on grouted cmu block cores with very little gaps under it and still connected to a bottom slab that is 5.5" thick ... and got lots of fibre on slab. I can't imagine the oven can produce enough moisture to saturate close to 3 tons of concrete between firings . I most likely be a light user of the oven, may be fire it few times a year or so (not good to plan to design it so though). I have a feeling that weeping holes would be more suitable for large open span slabs with wood being stored under the oven that the slab would be bowed in centre creating a gap between the oven base and the slab where it will get filled with no emptiness but moist air. My priority in my oven is to have extremely rigid and stable foundation that will not propagate settlement to oven and water should not get on it. I still have close to a month to research it more and decide , for now just waiting for concrete to cure.

any help about my insulation stack design and if I should use castable refractory for dome wall support or instead use a 1/4" mild steel sheet one? as I am not using tiles under the dome walls, the ceramic fibre board and perlite if they creep or settle could cause settlement on a half brick and that if combined could cause a dome instability, so wanting to put a very solid doughnut under the dome walls ONLY while hearth can be on its own ...

The problem is that water is conductive, air is not. This leads to moist insulation not working as an insulator. This fact combined with water in a liquid state creating more than 1500 times its volume as steam when heated, means that small amounts of water will negate the insulative quality of the insulation. Every oven owner becomes surprised by just how much is generated and how much difference it makes to the efficient operation of their ovens.

Any mild steel used in the build particularly if thin, is prone to corrosion from the combination of heat and moisture, always use stainless.

[IH123]

it all depends on the form of water and where the oven is. In Calgary, water is:

-water=ice
-water=nightmare in -40C, -20C, 0c
-water can turn ice from October to May
-steam water will turn to ice powder in cold weather
- water= damage as it expands and freezes


having weeping holes on slab in winter is not very useful because they will certainly get blocked and ice, only way to get them open is if concrete temperature rise above zero for a while which will not happen probably for hours of firing because of insulation and outdoor temperatures and wind .

A positive thing of living thousands of kilometres away from warm ocean with sun taken vacation for whole winter is outside air is mostly dry so water can fly free when not too cold


Therefore, protecting oven from downpour is the best thing someone like me can do, moisture build up inside oven will be limited to water content inside oven cooking chamber from food and fuel. The thinking of water coming from air vapour and becoming water pooled inside insulation will not apply much as I think dealing with designing an exist fo water from a confined place will be unworthy knowing the oven got a mouth and a chimney to vent off