Hello, Everybody!

[Orrin Dean]

I've always wanted a Wood Fired Oven. My uncle had one in Florida and he used it to bake bread , when we went to visit. My concern is that where I live it can get from 25? below - 110?F. Are there steps I have to take to prevent extra wear from the temperature?

Orrin Dean
All Fired Up!

[mfiore]

Re: Hello, Everybody!

Hello, Orrin. Welcome!

To start with, you will need a sturdy foundation to support the oven. Cold weather builders need to take frost heave into consideration. There are several threads discussing cold weather foundations, I suggest you search back a bit for very helpful options.

Many have suggested the need to dig the foundation to a point below your frost level. You will need to check with your local building code to know that depth. Here (Michigan) it is 42-48 inches. This is the option many of us have taken.

Other options discussed are to build the oven on a "floating slab" of concrete sitting atop very well drained crushed rock. I would discuss this with local builders, as they will tell you what is best given your particular climate and soil.

[dmun]

Re: Hello, Everybody!

Welcome Orrin Dean!

The discussion about deep cold region ovens is whether we build full footings under the frost line, or pour a pad on a bed of well-drained crushed stone. Members have done it both ways. Our most recent question on this topic was from a new member in Moscow, where they apparently have a five foot deep frost line.

There seem to be successful examples of both types of build.

As for the oven itself, it will take more wood to fire it in deep winter, but there are no special precautions you need to take.

[Ed_]

Re: Hello, Everybody!

Here in central Iowa, the recommended depth for below-frostline footings is 42"-48". That sounded like a lot of digging to me, so I've been looking into other options. If you do a search for "frost protected shallow foundation" you'll find lots of information.

One article I found useful was this: ESB: Frost-Protected Shallow Foundations. The diagram at the end is particularly relevant to WFO construction. I think I'll do something similar, but I'll be interested to hear what you decide.

As mfiore said, there's also a lot of discussion in older posts on this forum.

Ed

[dmun]

Re: Hello, Everybody!

Thanks for that link!



Note that this technique requires high density foam insulation, not the pink stuff from HD, and superior drainage both above and below grade.

[mfiore]

Re: Hello, Everybody!

I think a lot of it depends on your soil conditions. I spent far more time agonizing over the deep footing then actually digging. Once I started digging, it wasn't too bad, and was able to knock out a 48 inch deep, 16 inch wide trench in a few afternoons.

[Orrin Dean]

Re: Hello, Everybody!

We have a lot of heavage due to the high amount of clay in our soil. Our patio and sidewalk are cracked from the expansion and contraction. Is this a matter of digging post holes or are we talking a small ditch?

[dmun]

Re: Hello, Everybody!

A sonotube post in each corner is the worst solution. It just gives the ice lenses something to grab onto. It's either full footings on bare soil below the frost line or a slab floating on well drained fill. That link in Ed's post above is very informative. You also might look at this:

CBD-26. Ground Freezing and Frost Heaving - NRC-IRC

The Canadians should be the masters of frost heaving.

[mfiore]

Re: Hello, Everybody!

are we talking a small ditch?

Not really "small". If you go the route of a trench, then it needs to be deep enough to go below frost-line, my guess is at least 42-48 inches in your area.
Here is an example of my "ditch".

[Orrin Dean]

Re: Hello, Everybody!

If I have 'my ducks in a row' how quick can I get this built?
I can guess how long it can take!
I'm wondering if I plan a long Memorial Day Weekend next year, if that would do it? I also want at least another day for set backs.

[gjbingham]

Re: Hello, Everybody!

If you had your plans in order and supplies on-site in advance, and had nothing but free time to build, you could probably pull off the oven in 5 or 6 weeks or so, with some occasional help from friends.

Waiting days/weeks for concrete and mortar to cure before you move on probably doubles the work time involved.

[Orrin Dean]

Re: Hello, Everybody!

So, taking you time can be benificial?
I guess the next question would be what steps are the most crucial?

Orrin Dean

[Ed_]

below-slab insulation strength

Note that this technique requires high density foam insulation, not the pink stuff from HD, and superior drainage both above and below grade.

They do emphasize in that article that you should look for the denser foam. I was just looking at Dow website for specs on the blue Styrofoam brand insulation board. The compressive strength varies a bit from product to product, but the low end is 15psi, which translates to over 2000 lb/ft^2. Seems to me that if you're doing a slab right on the insulation (rather than footings with fill as shown in the diagram), this is more than strong enough. (Especially when you consider that the reinforced slab will spread the load.)

Anyone know more about this? Am I missing something obvious?

[Orrin Dean]

Re: Hello, Everybody!

Is there a good post, article or resource that explains the purpose of each feature of a wood fired oven?
For example, a circular dome distributes heat better because radiation moves in concentric circles. But why the hearth and the vent in the hearth, etc...

[thebadger]

Re: Hello, Everybody!

Orrin,

I think the FB manual does a pretty good job of explaining the basics of the round WFO. You might also want to search the forum for more specific discussions.

Hope this helps.

Dick