Insulation question

[sonomacast]

I am in the process of building an oven using castable cement and by building my own forms, I have built the inner dome form and tomorrow i shall build the outer form and pour next week. The dome wall will be 70mm thick (3"). Due to lack of space after the dome is poured and the forms are struck there will only be 50mm left for insulation (Table size) so my question is this;
I work in construction and have got some foam insulation (We call it kingspan) It is a yellowish foam with a silver backing on each side. (Fantastic insulation.) The sheets that I have are 25mm so I want to know would it be a good idea for me to sick this insulation to the outside of the inner dome then cover with chicken wire and then put on a 25mm render (Stucco) finished with a waterproof coating or is there a better way? Thanks

[eyepatch]

Very interesting

Hi, what you are doing is very interesting. Will you post any pics of your progress?

Good luck!

Mike

[sonomacast]

I will do that no problem. I want to build three ovens, the 1st by casting as I am a shuttering (Formwork) Carpenter by trade, (This one in my garden). The second on a trailer, this will be brick and the 3rd using Loam or fireclay using a sand dome as a mould. Then I can compare all pros and cons. (Time, Labour and Cost). I will keep you updated!