Salt under cooking floor

[zarzir]

Hi everyone,
Finally... Started building my first oven, done foundation and hearth and getting ready laying the cooking floor .
Some people told me to lay the floor on bed of salt instead of fireclay… saying it will have the same thermal qualities of fireclay and will absorb some humidity from the cooking chamber… to produce better and crispier pizza.
Does anyone have some experience with this?

[brokencookie]

No experience but a little chemistry background in desicants. The salt will definitely attrach water and bond with it, for a time. As it becomes saturated, it becomes useless. Driving the water off ( firing the oven) will work to a certain extent. Over time your salt will become contaminated and stop working.
I am not sure why you are worrying about this. If you look a some of the bread threads you will see people adding water ( misting) to get a higher humity. A 900 degree fire is sure to dry everything out.
Also, look at the FB pizza crust recipe. It has a 65% hydration for crying out loud. Any slight moisture from the cracks in the floor should not really have a huge effect. The crispy crust comes from a good recipe and the correct temperature in the oven.

Bruce

[DrakeRemoray]

I think some very old designs call for salt as an insulator instead of the FB board or vermiculite concrete. Salt is not a good insulator and should not be used in that capacity. The fireclay layer is strictly for leveling and it works well...

[dmun]

This is a hang-over from a traditional ineffective under-floor insulation technique. Don't do it. Salt reacts with ambient moisture to produce sulfuric acid (see northeastern US automobiles) that will attack your support slab and it's rebar. Plain sand would be better.

What insulation are you using under your oven floor?

[zarzir]

Thanks!
I’m using vermiculite concrete under the cooking floor,
The salt idea didn’t sounds that good to me and suspected it to be hanging-over from traditional isolation method… I’ll stick to fireclay and sand.