New Build Darlington

[stew1971]

Hi all

Newbie here who has been lurking around the site for a while picking up tips for my first, and probably only, wood fired oven build.

I think I have my plans sorted now but would appreciate a critical eye or two being cast over them to see if there is an obvious flaw anywhere with my build.

I’m doing a Pompeii, I have the base/pedestal complete, built out of reclaimed solid red brick, and I’m about to set loose laid fire brick into the middle of the base (the inner footprint of the dome).

I’m intending to build an inner dome of more fire brick, bonded with refractory mortar, then an outer dome of the reclaimed solid reds in standard mortar.

If I can form the outer dome neat enough (I’m by no means a bricklayer) I’m going to leave it at that as I like that ‘mosaic’ effect. If it’s not neat enough I then intend to render the outside with a standard sand/cement render.

I have two concerns I’d appreciate some advice on.

One – do I need a layer of insulation between the inner and outer domes, or would the outer dome act as sufficient insulation in itself?

Two – would the outer rendering need to be some sort of refractory render or is a standard render up to the job?

Many thanks in advance of any advice.

Stewart

[oblertone]

Welcome to the forum; you will need to separate the inner & outer dome, otherwise the heat will just continue to leach out. A layer of 50mm insulating blanket would be the 'gold' standard, then a shell of chicken wire and a light render coat before applying your finish of choice. If you intend to use reclaimed brick on the exterior then I suggest you split them lengthways to produce a thickish tile. If going down that route then your render over the chicken wire could be ordinary bricklaying mortar.

Any particular reason you are planning on using refractory mortar for the inner dome ? I ask because it is expensive and has no advantage over homebrew (3-1-1-1 sand-cement-lime-clay).

Hope that helps.

[stew1971]

Thanks oblertone.

I'm using refractory mortar purely because at the time of buying I wasn't aware of the homebrew. I now have three bags of refractory, so might as well use it!

If I use the 50mm insulating blanket over the inner dome could I then do away with the outer dome of reclaimed bricks, and apply a finishing render? Obviously the thicker the dome gets the more room inside I will lose, as I'm now constrained by the size of my base which is already built.

[oblertone]

You can indeed just render over the insulating blanket, most folk find that a cage of chicken wire gives the render something to grip to and saves the blanket from being compressed too much.

[stew1971]

Jun 28, 2016 13:34:20 GMT oblertone said:

You can indeed just render over the insulating blanket, most folk find that a cage of chicken wire gives the render something to grip to and saves the blanket from being compressed too much.

Thanks again.

Presumably ceramic blanket is the insulation of choice in this sort of application? Can you recommend where to source such insulation, or even suggest an inexpensive alternative?

[oblertone]

I think I got mine from eBay, but try a search for Kilnlinings or one of the sponsored links on here. Alternatives have been used but for best results in a confined space you can't beat it.

[stew1971]

So this is where I'm at with my build:



I stripped the temporary support to the dome out last night and, thankfully, it's still standing! When having a good look inside though it seems like some of the joints could do with pointing.

Obviously pointing them is not going to harm but, because it's going to be a difficult job, do they even need it if the joints on the outside are well sealed?

[tim1989]

I pointed lower joints for looks but left the top! Who's ganna look up after u give them a pizza?

[stew1971]

Finished!

[oblertone]

Very neat finish, just be careful regarding the size of the 'curing' fires, too much too soon can cause problems so aim to take at least a week with progressively larger fires for longer every day. Did you use an insulating blanket or is that yet to come ?

[stew1971]

Jul 19, 2016 9:20:59 GMT oblertone said:

Very neat finish, just be careful regarding the size of the 'curing' fires, too much too soon can cause problems so aim to take at least a week with progressively larger fires for longer every day. Did you use an insulating blanket or is that yet to come ?

Yes, there is an insulating blanket under that render.

Thanks for the advice.