Re: foil under base element
I might add that although the loss of a small amount of metallic foil wouldn’t cause too much concern. It has to be substituted in the way that has previously been suggested as too much heat loss downwards can cause the base of the oven to overheat and burn the cabinet on which it stands.
The bottom oven lining is jacketed with double sided aluminium foil and glass fibre and held in position with a wire or steel straps. It’s thermal qualities in retaining the heat inside the oven cavity should never be compromised. So please take care. 😉