Of course I will stand by my product
That said for your own satisfaction as a consumer make sure freezing temp are covered by the warranty for the dome and the floor.
We do for the FGM ovens.
Our ovens come with 2 doors, cast iron door and insulated door. This helps ensuring the oven stays nice and dry, which is crucial.
I had a customer who told me he was cooking in blizzard conditions, only issue he reported was his hands freezing to the peel
As Stonecutter said, if you are in a deep freeze, you want to break out the cold slowly. A small fire the evening before cooking helps. Otherwise do a smaller fire for an hour, then you are good to go.
The quality of the materials does make a difference.
On our ovens the metal fibers in the refractory concrete and the smaller tiles do help prevent any cracking. However on the larger ovens we use larger tiles, 13" by 13" and 2"1/2 thick. Even the ones on the trailers that are exposed to freezing temps don't show any cracking.