My first 1100mm WFO

[Garth Dye]

I have been reading, and reading and reading and now it is time to build.
My build will be a bit different to most that I have read about as I am going to build it off the side of my wooden deck which is 2.5mtrs off the ground. I will build the base on top of posts that are set into the ground, so my oven floor will be approx 3mtrs off the ground supported by the wooden posts.

I was lucky the other day as I found a source of second hand fire bricks for $1.00 each, brand new seconds in NZ are $4.60 each, so was a great score.

All comments and advise will be greatly appreciated will post pics when I have worked out how to do it.


Sorry have just realised I have posted this in the wrong place, how do I move it to the correct posting spot???

[lwood]

Sounds ok to me, post specific questions when you need help.

[dmun]

Ten feet off the ground on wooden posts? This sounds dangerous to me. We discourage even normal height wooden bases because they don't supply the rigidity to prevent movement and cracking. Your plan sounds sort of like building a WFO in a treehouse.

There's a reason in construction that they build the light wooden structure on top of the heavy masonry base, and not the other way around. I'd reconsider this plan.

[david s]

I agree, a wooden stand is not a good solution. A mate of mine built an oven on a stand about ten feet high using concrete blocks in a U shape. It is very successful, he tiled the outside and it looks great. I think this would be a better solution for you too. I could point you to a photo of it but I'm not allowed to post my website.

[lwood]

If the wooden stand is attached to the 2.5 mtr deck, so there are no lateral forces possible, I don't see a problem. Do you have typhoons or high wind to blow it down? It seems a little top heavy, but if you can secure it to the deck adequately, it shouldn't be a problem. I would also build some sort of supported steel pan to pour the structural slab into so you don't just support the corners.

That said, wood is not the best solution. Why not build a steel stand?

[Garth Dye]

Thanks for the comments and advise.
There will be not lateral forces and we are not in a high wind or have any other major weather issues.
The metal pan is a good thought and will look into that. The block base to me will be too much of an eye sore.
I have today just contreted the posts into the ground and will now proceed with the framework for the base. I intend to support the slab on top of wooden bearers 200 x 75 on edge, much like the floor of a house.
Will get some photos posted to show what I mean.
Thanks again for the posts.
cheers.

[Garth Dye]

Well managed to get some good time on the frame for the base and the oven.
I now have a question.

How much insulation does the conctret base give to the oven floor?.
I ask this because I am building my WFO on a wooden stand and the floor will be completly supported (much like the floor in a house).
Do I really need the 100mm of concrete before I put my 100mm of perlite insulation then my fire brick oven floor?
Not having 100mm of concrete will not only save me noney but also weight on the frame.
If the base does not get too hot I can fill base from below with pink bats (house fiberglass insulation), have a base of plywood on top of them then my 100mm of perlike insulation (could go to a 150mm layer of perlite insulation) then my fire bricks (75mm thick).

All this is based on the heat that moves down into the concrete layer and how hot it can get, I assume that 150mm of perlite insulation should stop the vast majority of the heat moving down.

Also how do I move this post into the newbe forum and so not have it here in the guideline, i apologise in advance for posting in the wrong place.

Cheers from NZ

[brickie in oz]

Originally Posted by Garth Dye

Well managed to get some good time on the frame for the base and the oven.
I now have a question.

How much insulation does the conctret base give to the oven floor?.

None the concrete will add thermal mass.

Originally Posted by Garth Dye

Do I really need the 100mm of concrete before I put my 100mm of perlite insulation then my fire brick oven floor?

Yes

Originally Posted by Garth Dye

can fill base from below with pink bats (house fiberglass insulation),

No, house bats wont cut it.

Originally Posted by Garth Dye

All this is based on the heat that moves down into the concrete layer and how hot

the heat needs to be stopped well before it gets to the concrete.

Originally Posted by Garth Dye

Also how do I move this post into the newbe forum and so not have it here in the guideline, i apologise in advance for posting in the wrong place

You cant, you need to contact a forum moderator.

Having read all your questions and seeing your post stating.

I have been reading, and reading and reading

I guess you must of missed a lot or reading.

[dmun]

I ask this because I am building my WFO on a wooden stand and the floor will be completly supported (much like the floor in a house).

See my post above. Wood stands are not a good idea. Building your oven on wood planks or plywood is an even worse idea.

Wood moves. Masonry on top of wood moves and cracks. When an oven cracks in a live fire situation what keeps the fire away from your wooden tower? This is next to your deck, right? Your deck is attached to your house? I don't think I'm being alarmist to recommend again that you re-think this idea.

[david s]

Too late he's already built the stand. Moist masonry over plywood is also a recipe for failure IMO