Hola! Base Question

[Soaks]

Hi guys

First off I wanted to say what a great community you guys have built. The info and guidance is amazing, I've been reading for about 6 months, now its time to break ground on the WFO.

Few questions if I may, I am planning a 36" oven (in sketchup only so far!) and man the foundation seems large! When I decide how I intend to cover the dome I guess I can adjust the base size.

I have read a few times that the block goes down dry fitted onto the foundation and then concrete is poured into every other void.

Is that correct? I dont need to mortar the block together at all between courses and between blocks? The weight holds it altogether? And when I pour the top slab (4" slab that the insultation sits on) do I allow the concrete to form down into the empty voids, creating one large concrete monster? Or is that why we stuff bags into some of the voids to stop the concrete dropping down into the current empty voids?

Hope that makes sense? Sorry for such a basic question, just cautious about foundation given its the most important part of the oven staying, well, in place

I'm looking forward to the build and watching others build their WFO's. I'll post some pics once we get underway.

Rob

[papavino]

Re: Hola! Base Question

Rob,

I'm currently at the stage of dry-fitting my blocks together and I think it is okay to not use mortar. I'm going to fill the corners and the stand arch plus a few others just for good measure.

I think you have the right idea about filling voids with concrete bags. No need to fill them, so block them off with something you have plenty of. And after building a foundation, we have plenty of empty bags!

[thebadger]

Re: Hola! Base Question

Soaks,

The base does seem big but by the time you add the brick, the insulation and finish materials you'll be right to each edge or so...

Correct, no need to mortar the joints - you can if you want but trust me once you fill the voids it's not going anywhere...

I actually filled every core to the below grade level and then every other core all the way to the top. No need to let the concrete drop down when you pour the base for the hearth. I just stuffed them with used concrete bags.

Good Luck and keep us posted.
Dick

[Rastys]

Re: Hola! Base Question

A variation to the theme (if you prefer).
Here in Australia, it is customary to cement the blocks together for strength and rigidity. Yes you can fill the corner blocks and even put reinforcing rods through them if you want to tie the whole lot down as in a roof of a building.
You can even knock/chip/cut out a channel in your top course and fill them with concrete and rods for strength as in a lintel but not justified for an oven base or tank stand which would hold considerably more weight supporting a reasonable sized tank.
You could also reduce the size of your base dimensionally if you wished to cantalever the top slab over the edge bu say 6" or so. Instead of boxing/framing up the top slab, you could also use concrete posts, sleepers etc and pour a reinforced slab over that or just add your vermiculite insulation layer. After all, the total oven weight would then be directly over the walls and not inside of them.
Anyway, get it going, the sooner the quicker you will be enjoying it!

Rastys