Foundation size for 42"

[irelande5]

Hello all,

Looking at the plans/manual, there is a discrepancy on foundation size, on page 66, it states 80 x 94, on page 13 it states 73 x 86, what size should I make for 42" pompeii style?

Also, live in NE Ohio and soil conditions here are lots of sand, should I go with floating slab, or pour footers?

Thanks for your time,

Pat

[deejayoh]

Re: Foundation size for 42"

Didn't look at the doc but the rough width of a hearth for a 42" is 42 + 9 for dome walls + 6 for insulation + 8 for walls = 65" wide. The foundation slab is ~8" wider than the hearth - so 73" sounds right for width.

Lots of differing opinions on the floating vs. footers question. I didn't have to worry about it for my climate, but here are some good threads
http://www.fornobravo.com/forum/6/fo...b-15604-2.html
http://www.fornobravo.com/forum/f8/s...ion-16327.html

[Gulf]

Re: Foundation size for 42"

Hello all,

Looking at the plans/manual, there is a discrepancy on foundation size, on page 66, it states 80 x 94, on page 13 it states 73 x 86, what size should I make for 42" pompeii style?

Also, live in NE Ohio and soil conditions here are lots of sand, should I go with floating slab, or pour footers?

Thanks for your time,

Pat

Go monolithic (footers and slab with the proper reinforcement) in the same pour! Footers,then block, and then slab should only be used on uneven grade (hills) and covering some distance. IE: The distances occurred in a house on an even grade. The short distance covered by an oven foundation would be well within the guidelines of a monolithic pour. It will be stronger.

[Les]

Re: Foundation size for 42"

Also, live in NE Ohio and soil conditions here are lots of sand, should I go with floating slab, or pour footers?



Pat

Pat,

If you are on sand I don't think you need to worry about frost heave. We get pretty cold here and I built on DG (same as sand). I poured about 4 inches in the field an 8 -12 inches on the perimeter (it's been a while). Obviously drop in some steel and you should be golden.

[Neil2]

Re: Foundation size for 42"

Try for at least 1 % rebar by volume for a floating slab.

[Dino_Pizza]

Re: Foundation size for 42"

Pat,
If you look halfway down this page of my thread
http://www.fornobravo.com/forum/8/di...s-5883-63.html
I have just posted 2 pdf files of my 42" oven block stand. The block stand itself is about 70" by 80". The foundation is only an inch bigger in each direction. The 1st pdf has the 1st row of blocks on the left with the dimensions shown.

It's all about (at least in my opinion or way of thinking) being forced to use our normal building materials in the area or country we live in. If your ovens block stand is going to be made of 8"x16" concrete block, it's easiest to use those dimensions (or the half-blocks most brick yards sell). As you can see by my pdf's that's why I had those dimensions. I always felt I could have gone 1/2 block shorter in depth (8") if I want to cantilever a larger front counter, which I chose not to do.

Hope this helps, good luck,
Dino

[Mingy]

Re: Foundation size for 42"

Unfortunately I made the mistake of using the smaller dimension - this should be corrected in the book. I made the wall from the dome up in 4" block, and there is very little room (about 1" for insulation). So, go big.

Also, you should consider whether you will be putting stone or brick on the outside of the blocks. If so, you will want a 'ledge' to hold those up, and make sure that the ledge has perpendicular rebar in it. I had a 4" ledge, 6" would be better as I am covering with natural field stone.

With respect to the foundation, for some reason people on this site seem to think ovens need footings for frost heave. Unless you are attaching to another building, this is not necessary. A floating slab with rise up a tad in winter, drop down a tad in summer - no harm done. The one thing that would concern me about sand is whether it would be stable enough. My soil is 'sandy loam' which translate to 'hard as concrete when undisturbed'. Either way, if you dig footings, unless you hit rock or something, stability would be an issue. In fact, a floating slab would have more area to distribute the weight than footings so it should be more stable.

Make sure you remove the topsoil, though.

[irelande5]

Re: Foundation size for 42"

thanks all for your great advice