Constructing a dome oven in rainy Manchester

[Matt Gartside]

As most i looked at many posts before my build and it has changed directions mid route after seeing a lot of failed domes due to water ingress and strength issues.
My build is a 48inch corner slab mounted on oak sleepers , reinforced concrete , bottles , vermiculite - now just about to look at ways of keeping excess water off the slab and calcium silica board dry with firebricks on top.-- potentially looking at drilling the slab and mounting the board on mosaic tiles ---ANY ADVICE WELCOME

The dome was initially a cast vermiculite done over an exercise ball , this then changed to a grog and cement with metal fibres cast on the ball again , -- before a stroke of good look found me a cast GRP ( fibreglass ) 42 inch shell.This was ideal for our climate and should stop any issues with water ingress into the dome .
i have put 25mm ceramic blanked , chicken wire , then cast the grog /cement mix into the dome -- the results are outstanding and the structure is solid (fingers crossed).

i could leave the dome in its original finish , or tile the outer

i have attached some pictures

[david s]

Can you remove the fibreglass outer shell so you can drive off the water from the casting?

[Matt Gartside]

it would be possible , but wasnt planning on doing that , as you will see i have three and this is the prototype so not too worried if things go wrong.
do you not think it would dry out naturally over a couple of weeks ,

[david s]

When you light fires, how will the water escape?

[Matt Gartside]

forgive me for sounding a complete novice , could i light a fire in it inverted , then steam would work its way upwards

[Matt Gartside]

When you light fires, how will the water escape?

David , what are your thoughts on drilling a hole in the top just through to the blanket layer as a steam/vapour release vent

[david s]

David , what are your thoughts on drilling a hole in the top just through to the blanket layer as a steam/vapour release vent

If it were mine apart from a hole at the top I'd be making some near the base of the fibreglass dome so condensing steam hitting the cooler inside surface of the fibreglass shell will run down to the base. You can always plug these up later. As moisture will always travel in the opposite direction of the heat source a fire inside the inverted dome is unlikely to be very successful. Sun and wind are pretty good though and far safer.

[Matt Gartside]

i have had an idea for cheap vent hole in stainless steel , i think one of the stainless steel straws which are now readily available and already bent would do the job - only a couple of pounds

[Matt Gartside]

So my prototype pizza oven has been tried and tested.The steam vent worked a treat , no cracks whatsoever on the dome and gradually cranked up the heat to 600 , thanks for the advise David. Produced some fabulous restaurant standard pizzas (so my friends said).
Tried a small mosaic glass section on the entrance to check the adhesive was suitable.
I will now produce the much larger version i have

[Matt Gartside]

larger version coming along nicely , just sewing up a bespoke cover for the winter