New member, new build.

[The foxdale phantom]

Just throwing something out there, has anyone ever considered pouring the hearth on the ground then lifting into place? Understanding that one would require the space to do this and the means to lift it into place, + install lifting anchors.
A random thought when considering where to put possible excess from slab pour

[The foxdale phantom]

Testing some photo uploads of IT I’ve built ……and successfully. Whist at Bunnnings looking to purchase an Irwin Quick Grip bar clamp for an IT I spotted these two Stanley bits of kit that i have modded . Will make a brick sized block of timber to set in floor and install socket (25mm Poly pipe fitting) to accommodate the ball end.

[UtahBeehiver]

There are a couple critical design items that need to be factored in order for the IT to work correctly. 1 - The line from the floor elevation pivot point "must" intersect the mid point of the brick face. If it does not, a stepping of the brick face will occur and it gets progressively more severe as you work you way up in courses. This design element is to ensure the the brick face is perpendicular to the center of the floor elevation pivot point. 2 - By raising the floor elevation (wood block) this affects the oven size, ie it will be 47" at the base and 47" plus the wood block thickness at the floor pivot point. This can be corrected two ways, first, make a wood block the size of the floor brick and place where the floor brick will be and lowere so pivot point is at floor elevation or second, adjust length of IT and you move up in course to match you desired ID of the oven. You need to work this design items in the oven or the IT will not work as desired. PS Karangi Dude has a large thread of WFO cooking outside pizzas.

[The foxdale phantom]

UtahBeehiver , yeah plan is to make a timber block, brick size to lay into floor. I’ve added a edited pic of IT showing a red line from centre of pivot point to brick face , does this look ok?

[UtahBeehiver]

I can't see the pivot point side on the pic. Just make sure the pivot point is at the floor elevation and not raised off the floor. Otherwise looks good, beefy, and adjustable (which is good, since there are so many variable in building one of these beasts).

[The foxdale phantom]

Had the block layer complete the hearth stand.

[Gulf]

Referencing posts #12-#14: Will that be "dead space" in the hearth stand next to the tall vertical block wall? Looking back on our conversation, I now believe that you were asking about support in the footer, I was wondering then and now about supporting the hearth slab in the back?

[The foxdale phantom]

Yeah filling the void with sand Gulf and adding reo bar to tie it all in pics to come

[Gulf]

Before filling the void with sand I would lay a course of filler brick along the back wall for support. That's just me. I'm sure you've got this.

[The foxdale phantom]

I’m adding some 20mm pvc for weep holes in the hearth and contemplating wether I should bother with them on the side/back were they will be leaching any moister into the sand filled void? Any thoughts/suggestions on this would be appreciated.
Attached picture shows the sand filled void . Black plastic and more reinforcement to come.

[david s]

Have you drawn a detailed plan for your 47" ID oven to fit on your supporting slab?
My rough drawing suggests that a 47" (1194mm) would be extremely tight. The last thing you'd want is to have the oven outer shell outboard the edge of the slab. A lot depends on whether you are doing a brick or cast oven, thickness of inner walls and insulation layers. A brick build usually has 4" (100mm) inner dome then the insulation layers. My rough drawing may not be correct, but a careful check at this stage could prevent a lot of heartache caused by an oven too big for its slab.

[The foxdale phantom]

Have you drawn a detailed plan for your 47" ID oven to fit on your supporting slab?
My rough drawing suggests that a 47" (1194mm) would be extremely tight. The last thing you'd want is to have the oven outer shell outboard the edge of the slab. A lot depends on whether you are doing a brick or cast oven, thickness of inner walls and insulation layers. A brick build usually has 4" (100mm) inner dome then the insulation layers. My rough drawing may not be correct, but a careful check at this stage could prevent a lot of heartache caused by an oven too big for its slab.

Thanks DavidS 48’ was my planed sized bricked WFO. Have just thrown my internal diameter template up on the future hearth and have been trying to do a calculation on finished dimensions . Was posted somewhere on this forum, it is a wealth of information I’m wishing i had have left important stuff I’ve found in open tabs or written down as now I find myself searching again. The excel dome calculator gives me approx a 708mm outer radius then I’m thinking add 50mm for insulating fire blanket then I’m not sure what a finished rendered thickness would be.

If 48’ becomes to tight of a squeeze happy to lose an inch or two.

[david s]

A layer of lean (8:1 or 10:1) vermicrete over the blanket layers to even out the soft uneven lumpy blanket surface and to provide a firm substrate for the outer render, usually requires at least 1.5 to 2” (35-50mm) of thickness. (I never bother to secure the blanket with chicken wire though most builders do, because it takes ages, tends to compress the blanket which reduces its insulating capacity and adds a conductive material inside layers that you want to be insulative).
Then allow around 15-20mm for the outer shell, maybe more. Also check the thickness of your firebricks, there are many different sizes.