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Post by davidj on Feb 13, 2016 10:23:22 GMT
I'm thinking of building a WFO and was going to construct a complete slab then block base for it in front of an existing wall. It's occurred to me that I could save some space (and some building) if I moved the whole thing backwards....ending up with the main weight of the oven resting on the existing wall and the earth behind it. I would of course need to lay a small slab and block work in front of the wall, then lay a top slab across the whole lot.
So question is, has anyone got any experience of doing this?
My thoughts were to remove a couple of layers of the stone from the wall. Then to remove the soil to the correct level, and dig a trench for the outer blocks. Concrete in the bottom of the trench, then a layer of block to the level of the front section.
Then I'd need to lay slab across the whole lot, which would give me the base for constructing the oven.
It it sounds ok to me but I've never done it
Thoughts and suggestions appreciated.
David.
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Post by chas on Feb 13, 2016 13:49:41 GMT
Hi David, and you seem to have a grasp of the civil engineering required, and all sounds do-able, but if your idea by building out front is to give some toe-room (good idea - most of us have the useless 'woodstore' for that) why not cantilever the floor forward say 9" to a foot using lintels and slabs and save some building. Given enough depth of preps behind the wall, you'll have plenty of scope for a good thickness of insulation beneath the slabs - and on top, between slabs and floor finish - and the existing wall will bear most of the weight. The part of the oven you need to insulate least will be the uninsulated entrance bit out front. You may not even need to remove anything from the top of the wall... if it's at a convenient working height. Even better, if behind the wall is lower, you won't need to do much digging. It's the gift site that keeps on giving!
Chas
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Post by downunderdave on Feb 13, 2016 22:19:52 GMT
If that wall happens to be on your property boundary be careful. I don't know what your council regulations would be, but in Australia most councils require anything that's built to be no closer than 1.5 m of a boundary. This can become a problem if a vexatious neighbour made a complaint to the council. You could be forced to move the oven which would necessitate.a tear down.
Having said that my own oven is hard up against my boundary wall, but my neighbour has one of my ovens in the same place on his side of the wall. Should he sell I could end up with the neighbour from hell... Hope not.
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Post by albacore on Feb 13, 2016 23:12:21 GMT
(good idea - most of us have the useless 'woodstore' for that) Chas Chas, I think you have an unreasonable "down" on the woodstore as a concept. I find it a pretty useful place for er, storing wood! I don't have a lot of alternative undercover space for storing it, so it comes in handy for me. More by accident than design, my woodstore has a reasonably wide opening and I think that this good access is the key to having a worthwhile woodstore. I urge anyone at the planning stage of a WFO to make sure that they have a decent opening into the woodstore and not compromise the store with extra internal support walls. Mine is 660 wide by 600 tall - not perfect, but better than many. A planned upgrade for this year is to make a wheeled wood storage trolley that will live in the woodstore and roll out for filling/emptying - I've got as far as buying the wheels! Lance |
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Post by davidj on Feb 13, 2016 23:31:52 GMT
Thanks for the responses. Great idea chas. It would look really cool with the front just floating. My concern would be if the current wall can take the weight. There are a few cracks in the mortar already. I think having a small slab and block work supporting some of the load would put my mind at rest a bit. I might have to investigate that idea more though.... downunderdave, the wall is not near the boundary so no issues there. In terms of planning though, do I need to inform the planning office I want to build a WFO, even if it will be nowhere near any neighbours? |
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Post by downunderdave on Feb 14, 2016 1:04:30 GMT
downunderdave , the wall is not near the boundary so no issues there. "In terms of planning though, do I need to inform the planning office I want to build a WFO, even if it will be nowhere near any neighbours?" That is not a requirement where we live. If you check with your local authority they may have some, but you're only building an outdoor barbeque, but make sure the top of the flue is well away from anything combustible. I avoid them wherever possible because they tend not to let you do what you want and also charge you a fee for the application. |
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Post by chas on Feb 15, 2016 11:48:06 GMT
(good idea - most of us have the useless 'woodstore' for that) Chas Chas, I think you have an unreasonable "down" on the woodstore as a concept. I find it a pretty useful place... Lance Don't mean to diss your store Lance, and of course you're right: in the absence of anywhere else, it's a waste to fill in with a front wall. My experience is that dry, seasoned wood absorbs moisture (from the atmosphere?) to a level that's really disappointing. If at all possible, store your wood elsewhere, anywhere, dry. My store - apart from providing toe room - has a collection of tools in it plus beer crates to sit on. Chas |
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Post by downunderdave on Feb 15, 2016 19:03:06 GMT
Chas, I think you have an unreasonable "down" on the woodstore as a concept. I find it a pretty useful place... Lance Don't mean to diss your store Lance, and of course you're right: in the absence of anywhere else, it's a waste to fill in with a front wall. My experience is that dry, seasoned wood absorbs moisture (from the atmosphere?) to a level that's really disappointing. If at all possible, store your wood elsewhere, anywhere, dry. My store - apart from providing toe room - has a collection of tools in it plus beer crates to sit on. Chas If you build the oven oven stand so the front and back are open it provides air flow so the wood will remain dry. In the case of the retaining wall at the back you can have both sides open instead. This has two advantages, one is that it's safer in that dropped coals are not going to present a problem setting fire to your wood and secondly you don't see an untidy wood storage from the front of the oven. |
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Post by davidj on Feb 15, 2016 19:54:18 GMT
Quantity questions...
For a barrel oven, how many firebricks do I need, approximately?
I'm thinking about 200.
I'm presuming 230 x 115 x 64 is the size to use?
About 14 per arch, four arches =56.
About 80 for the floor.
About 25 for back wall.
About 40 for the front arch (front of the main chamber, not the entrance arch) and the transition.
Have I forgotten any, does this sound right?
Fireclay, how many 25 kg bags will I need?
I presume I need some for under the hearth bricks (optional I guess), and some for the fire mortar for the arches, back wall and front arch/transition.
Vermiculite, if I'm using it just over the main chamber in the insulating layer, is one 25kg / 100 litre bag enough?
On the subject of insulation, for under the hearth slab, I guess I have a choice of casting a 4" layer with vermiculite....or using thermalite blocks. The blocks are £1.02 each at my local Selco, so it seems like a cost effective solution.
Anyone got any experience of using them?
Thanks in advance.
Edit...
Actually, just looking at the pics on Rado's site and I think I'm going to add 10 thinner (51mm) bricks onto this for the actual arch on the front of the main chamber...as its a little smaller than the main arches.
And, I won't need 40 for that arch (which was my guess above) but I will need some for the bottom of the walls, so I think the final number is about right.
I wait to be corrected though.
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Post by albacore on Feb 16, 2016 20:47:23 GMT
I would recommend a proper insulating board under your oven floor - 50mm calcium silicate for preference. It will have much better insulating properties than thermalites or vermicrete. You could sit in on a layer of thermalites to get the best of both worlds.
Lance
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