dome / arch sizes

[my2girls]

hi all

I have started my Pompeii build yesterday, I have my timber sleeper base constructed and im ready to now make my slab.
I have measured the footprint of the oven out onto a board and made a form for the arch which I calculated using the info I read on other peoples builds, I am however unsure if its correct as it doesn't seem to look like others I have seen.

so :

my internal oven size is 810MM, I get the dome height to be 405mm (50%)
the arch opening to be 405mm wide (50% of dome width)
and the arch height to be 255mm (63% of the dome height)

how do these measurements look? it just seems a little small to me .

also on other build the arches seem to start with bricks either side of the arch giving the arch flat upright sides before the curve and mine is curved from the base , is this right ?

any help to clarify is greatly appreciated.
thanks

[chas]

Well, what you have there is a perfect hemisphere, a classic build and if it is a little small in diameter, it ain't by much: mine is (sorry will have to revert to Imperial for a mo) 4 feet base less 9" brick ring = 30" internal = 760mm.

The one or two 'starter' courses you see on some give a bit of vertical before dome building. It will increase height inside but will also give you 'shoulders' around the inside rather than an instant slope... maybe easier to rake out ash. It will also allow you to raise the door height = 225mm isn't much to work in.

In my case I had an old door I wanted to build into the oven, and that determined overall height - hence a couple of starter courses.

Chas

[my2girls]

So could I just add a starter corse to my plan or will it give me performance issues ?
Thanks

[chas]

I don't know that the oven will perform much differently, but you'll end up with an internal height of nearer 500mm and 63% of that is 315mm. I'd say that may be a better door height to work with - you are going to have to reach in there and build fires, rake ashes, retrieve those pizzas! 

Hopefully, someone out there with an oven just your proposed size will chip in with some informed info...

Chas

[kstronach]

my ovens a 34" (860mm) so not to much bigger than yours. my internal door is 18"/460mm wide and 10 3/4"/275mm high this entrance is a semi circle rather than the straight sides. i too was going to make my opening 16" but increased it to 18 as i thought 16 a bit tight! my landing arch and entrance is 20"/510mm wide and 12 1/4/310mm high this leaves an inch at either side for my door to butt up against. this arch was built with the straight sides and just an arched top, i thought this would allow a bit more room for maneuvering things in and out. if you have a quick look at my build theres pictures of the arches. i've had no problems with access or any heat loss problems etc.

keith

[cobblerdave]

G'day
I've got an oven mouth of 300 odd mm but the thats with a mtre oven. You really have to make the oven dome a whole lot bigger to gain a little more height for the oven mouth. 300 mm has meant there has been nothing that I can't fit into the oven. I could easily see myself being able to use an oven with a lower oven mouth height. Check out the spacing of the shelves in your domestic oven and you'll discover they are quite small.
As kieth points out making the entranceway a good size is important to make it easy to work your oven
Regards dave