Refractory concrete

[123brinkhurst]

Good morning all,
I am hoping to go for dome, shape oven which I was going to make out of clay, but they crack too easily and I've heard of Refractory concrete could I use that instead?
Will I need to insulate it on the outside?
I haven't made the pizza floor yet, would it be a good idea to make it out of the same stuff, and would I need to insulate the underside, as I have made a cavity with a door for storing wood and logs. I would be grateful for any help as always.

[dmun]

Will I need to insulate it on the outside?

Yes, absolutely.

would I need to insulate the underside

Yes, absolutely. Your oven will be useless without insulation. You will burn cords of wood and only bring it up to pizza temperature with the greatest difficulty.

Refractory concrete could I use that instead?

Refractory concrete is useful in places like the UK where firebricks are irrationally expensive. It is more difficult to use than ordinary portland concretes.

There are solid, and insulating castables. You want the solid kind for the inside of the dome. You will find that the insulating kind is far more expensive than vermiculite concrete, and has no particular benefit at the temperatures we use. Whatever you use to build your dome, you are probably going to want to spring for a firebrick floor. It's your cooking surface, and you may not be wanting to scrape peels over chalky concrete.

[david s]

You can cast the floor in castable dense refractory, however if you do it in one piece it is likely to crack because of the uneven heating and resulting expansion. It is expensive stuff, you are probably better off using firebricks without mortar between them.

[123brinkhurst]

Thanks very much for the advice lads

[brickie in oz]

Yorky.
Here is my build for a refractory concrete dome.
Ive since knocked it over an redone it in fire brick but it served me well.
Wood Fired Pizza Oven : BrikiWiki the home of online brickwork.

Cheers, from a Lancy lad

[123brinkhurst]

Thanks mate, will prob go fore fire bricks.