Right, if I start a build thread, that means I have to get on and build it
Technically the build started 5 years ago when we renovated the patio and built an area for an oven. Work, a house renovation and a host of other things got in the way but this summer looks like it'll have a bit more free time than recent ones so here's a chance to get it built at last.
The plinth below has been full of rocks and gravel for 5 years and now needs a concrete pad putting on top. I'll bring it out to the front of the stone work and it'll be 3-4" thick. First question, do I need to throw rebar in there if it's going to be sitting on rocks and gravel and enclosed by the blockwork walls or will it be fine just throwing a load of concrete in and smoothing it over?
I have a pile of storage heater bricks that I can use to make the floor of the oven. I also have a few hundred of these bricks, does having the holes in them mean they can't be used? If you're facing the ends in to the oven, they're still flat and wouldn't the holes just be additional insulation?
If not, I'll have to buy suitable bricks if I can't find them locally. I do have some nice curved end ones which would look nice for the outside arch.
A few pointers; your oven floor needs to be at elbow height of the most frequent user, any lower and you'll be stooping all the time which is not good, so you may need to build up a little. You can use building blocks (laid flat) for this as it'll provide an insulation layer below your storage blocks which is important. Your base is well contained so I wouldn't bother with rebar as it's not going anywhere. Try and find bricks without frogs or holes for the dome, holes will just reduce the thermal mass and efficiency of the oven.
OK, so it looks like I'll have to fill in a bit more concrete than originally planned, it'll need to come up to the top of the stonework at the back and sides and then I'll put the insulation down. Either that or I could put some thermalite blocks in to be level with the top of the stonework, run concrete in around them to create the rest of the plinth and build off from there.
So, now that the mortar's dry I need to bring the level up on the inside. That would take quite a bit of concrete but I have a pile of concrete building blocks left over from the wall building so I'm thinking I just throw some mortar in and level the concrete blocks on it to give a solid base and fill in the gaps around the edges with mortar. Then I can lay thermalite blocks on top as the insulation layer. Watch this space.
Just started a new build in East Devon! I've done the base and attach two pictures, with the shuttering still on. I'm now deciding what to put on top as insulation. Ceramic FB board is out of the question for me on price. I looked at Thermalite blocks and was advised by the manufacturer that they may split if you have a strong heat source next to them and they didn't like the idea of them being used on their flats, because of loading (but I didn't think that was a problem).
I''m heading towards a vermiculite/Portland cement mix under the cooking layer, I think but it will need to be 100 mm thick which is more than I designed in!
I priced up fire-bricks for the cooking layer and dome and quickly retreated from that so I'm now looking at two options, either a fire brick (I could probably run to 25 bricks to do this) or house clay bricks, which I got from Gumtree at a good price (I used them for the stand). The dome will either be 1/2 clay house bricks or one of these "home brew" cast domes that people seem to be using.
For dome insulation, I need to find out if the cast home brew one will provide enough insulation on its own or if a vermiculite concrete or ceramic blanket (affordable) is best.
What's your oven destined for? Pizza mainly or other longer roast foods as well?