Using stone

[Tim F]

Hi all,

I love the look of mortared stone combined with brick edging, and am thinking about making the stand for my oven with this method. My biggest question about this is how I would pour the slab for the dome to stand on. Would you build up a layer of stone around the edges of the slab to conceal the concrete, or just pour it on top of the stone and have it visible as a layer - maybe with the same colour cement as the mortar?
Or could you construct some supporting pillars inside the stone shell, and pour the slab on top of them, inside the stone work?

(examples attached)

Any opinions/examples? Is there a better way?

[nissanneill]

Hi Tim,
what stone are you planning on using?
Local limestone, Kanmantoo book leaf or even closer to home some Wistow stone?? (I think the Wistow quarry is still open albeit be on a much smaller scale).
No matter what stone, I would brick up the stand and use thinner stone to run a second layer up. The inner brick (or 4" cement block) wall can be invisible from the outside but will support the total weight of your oven. I would also include some brick ties in the mortar joints of the inner wall to tie the outer stonework and make it much stronger.

Neill

[Tim F]

Good question - I don't know much about different types of stone. I was thinking I might just use whatever I can find around the place - maybe get some spare field stones and split them roughly to the shapes I want. I'm not sure if that is practical or feasible though! I might look into some of the local quarries.

Do you think I could get away with some pillars of brick under the slab rather than doing the full 4 walls? I was thinking of a 2 brick wide column of besser blocks with filled cores in each corner and a couple in the middle. I'm mainly thinking of minimising the cost as the besser blocks are pretty dear.

[dmun]

How would I do it? I'd lay up the decorative stone base up beyond the level of the slab, then do some dry stacking of concrete blocks on the inside just to support the slab. With enough rebar, I suspect that just a stack in each corner would be enough if filled. Then i'd lay in wonderboard to cover the openings, and pour the slab. Just having the slab mate with the rough interior of the stone would stabilize the structure.

I really don't like the exposed edge of concrete showing.

[nissanneill]

Tim,
keep your eyes open in the Saturday's advertiser under building materials. The are often give away bricks and paving bricks just for the taking. The 4" Besser blocks are a little rarer and are usually around $1 for the 8" but I would keep the wall width down to a minimum.
You are going to need a substantial foundation no matter what you do. Cheap or free brisks will be easy to lay on the inside, they don't need to be neat as they won't be seen except by the person, probably you anyway, climbing in to either put or get wood out.
Run the bricks up to your 'under hearth height', probably around a metre, lay some used galvanised iron or decking, as it can remain there and does not need to be removed. That is how they pour second story concrete floors quickly and cheaply without having to hire props and buying the expensive forming ply. You will need to put some reinforcing timber bracing and props to support the weight of the 4 to 5" concrete base and 3" vermiculite cement insulating layer. You will also need some deformed reinforcing bar and weld mesh (I would put a double layer in it myself) and a little extra over your base opening.
I would then start the stone work, keeping it fairly thin as it will only be decorative and non load bearing. Run that up to just over the top of your hearth so that you can then put your tiles/slate/render on top for your work area or shelf. This will also depend on whether you do a dome or an enclosed/roofed oven. Once this is done, you can then pour your slab as it will also tie your top stone work into the structure.
You need to make some decisions and commence sourcing your materials.
Check locally around Woodside, there are plenty of farmers with stone collecting areas on their properties that would gladly let you get what you need for a slab of beer or the like.

Neill

[Tim F]

Thanks for the advice guys.
I did some experimenting today with brick and some field stone I have already and I don't think it's quite the look I'm after. I got some quotes on dressed stone but it's pretty pricey at $600 per pallet for book leaf or $460 for mixed wall stone. I'm giving it some serious thought though!

[Frances]

Um, were you thinking of something like this?

http://www.fornobravo.com/forum/f6/h...tand-2469.html (Hooray, Iinished the walls of my stand!)

Only from what I understand with more irregular stones. This is how I added the cement layer:

http://www.fornobravo.com/forum/f6/p...tion-2531.html (Poured hearth, questions about concrete and insulation...)

These stones were rather expensive, but for some reason I didn't like the idea of cement bricks showing on the inside of the stand. And I still like the idea of having a natural stone wall under the oven... but you may well do better listening to the experienced builders on this forum.

About the cement hearth on the walls, it rather depends how you want to finish the oven. I plonked mine on top with the edges showing because I've built an igloo and am tying in the edges with that part of the installation. Well, that and it struck me as being easiest . But actually I think the first version you posted would look best.

[Frances]

Oh, and check out the last contribution in this thread!

http://www.fornobravo.com/forum/9/st...html#post37948 (Stone Work Photos and Ideas)

[Tim F]

Thanks for the links!