Greetings from the frozen wastelands of Derbyshire

[MarkEnglander]

I have been set the challenge of building an oven by the first week in June. So far the base blockwork is in and 4 off 2' x 2' concrete flags have been placed on top but I'm now thinking of adding a layer of 3' x 2' flags on top so I have a 6' square base. I can always take the Stihl saw to it and cut down the flags later.

[Gulf]

Mark,

Welcome to the forum. Can you post a pic of your oven stand and what you have done so far? I'm having a little trouble with the termanolgy.

[MarkEnglander]

Will do it may take a few days I leave for site in the dark and return in the dark at the moment

[jonv]

Hi Mark,

Are you saying the concrete flags are in place of the structural hearth slab? How thick are they? Are they just ordinary concrete slabs? I would be worried about the strength of them. Most folks pour a pretty thick reinforced concrete slab with plenty of steel in.

What size oven are you thinking of building?

[MarkEnglander]

Over in the UK we have a pressed concrete flags which are more Utilitarian they are quite strong approx 50 mm thick so it would end up as 2 layers with the bulk of it being 100mm thick.
On top of the flags I've just asked our merchants if they can get vermiculite board or something like that approx 25mm think the a 50 mm fire brick on that.
As to the brick I had a pile but used them in a raised bed but we maybe knocking down a wall on a house in Manchester soon and they are what we call Handmade Cheshire's these would look good on the outer/ visible finished skin.

As to size I'm aiming for 1100mm internal diameter and approx 550 mm high internal.

[jonv]

I know the ones you mean. Personally I wouldn't use them to support an oven; I would need a lot of convincing that they are up to the job. Why not pour a slab with concrete of known properties and plenty of rebar/mesh in?

Looks like you will need to have the slab overhang the stand a fair bit, once brick, insulation and whatever you finish it in are added to the 1100mm. That shouldn't be a problem with the right materials though.

You might want to consider increasing the insulation under the floor brick; 25mm is not much regardless of material. Are you planning several layers?

Hope that helps.

[MarkEnglander]

the blockwork is H shaped and there is angle iron carrying the flagstones all are resin bonded together with Hilti resin