Additional Mortar Layer

[MK1]

What is the current thinking on adding a 2" layer of refractory mortar on the outside of the dome. I know it's been stated that this layer can add additional retained heat to the oven which is useful in bread baking. I assume it also slows the heat up times. The reason I ask is that at one time a layer of splits added to the floor was advocated for bread but I understand that was not effective.
Also what is the cause of cracking. I know that's a very broad question. I assume it has to do with differential heating of the oven, the dome absorbing heat faster and growing in relation to the floor and lower parts of the dome? What about circulation of air from the entry?
I was looking at Dino's cracks and trying to see what's going on.

Mark

[DrakeRemoray]

Re: Additional Mortar Layer

i have 1" extra on mine. It still heats up in about 45 minutes to pizza temp (though it is not fully saturated at that point, meaning if I took the fire out then the dome temp would drop quickly). One of my biggest problems in baking bread at the end of a pizza session is waiting for the oven to cool down. 2" might be too much mass, search some of my past posts, I have nearly killed myself trying to use all of the heat in my oven...

As to cracking, It is going to crack, be ready for it.

Drake