Cold climate foundations

[jderek77]

Just planning to build this year as I'm not sure all our frost is gone yet! Speaking of frost, should I follow recommendations for any other building in colder climates, i.e. the footing or foundation should be below any frost line?
That would make the project a bit more work, expense and difficult.
Thank you

[dougrappe]

Re: Cold climate foundations

I am just finishing up the base for my 36" oven. It's built from solid limestone on a frost protected shallow foundation. There have been a few posts on this subject. If you follow this link there is a detailed description of how this type of foundation works: ESB: Frost-Protected Shallow Foundations, the last diagram, for an unheated space is the relevant one for an outdoor oven. (originally posted by Ed last year)

This link: Revised Builder's Guide to Frost Protected Shallow Foundations (FPSFs) has very detailed instructions (download the pdf) and tables that will help you calculate insulation size and placement.

The tradeoff is going deep versus going wide, I only dug a total of 24 inches deep but for a 5' square oven base dug out an area approximately 11' square. Of course, the shallow foundation uses less concrete versus a deep concrete foundation with footing. I was confident choosing this method since the site has good drainage, which is the key to this type of foundation slab. It looks fine after the first winter, and there's no turning back now!

Good luck, hopefully others with more time in the ground will weigh in.

[dmun]

Re: Cold climate foundations

I did the one foot thick footings below the frost line, but I was building a two story chimney. I think the general rule is that if your oven isn't much taller than it is wide, you can pour a slab on a thick base of well drained crushed rock with confidence.

I'm glad to hear that someone has had success with the frost protected shallow foundations. The Canadians should know about freezing conditions!

[jderek77]

Re: Cold climate foundations

Thanks for such worthwhile assistance. Good luck with the rest of your oven. Please post some pictures.
James

[david s]

Re: Cold climate foundations

Why do you people live in such conditions !

[david s]

Re: Cold climate foundations

We only have to deal with cyclones and flooding

[jderek77]

Re: Why do I live in such conditions?

My wife and I ask that question frequently during January, February, March and sometimes April.
On the other hand, we rarely see tornados, never earthquakes, no real wild fires to speak of and hurricanes generally don't make it very well in the cold northern Atlantic ocean.
Mostly its accident of birth. By choice it would be Italy, probably Tuscany. Then you would see quite a pizza oven project!

[Neil2]

Re: Cold climate foundations

You can put it on piles. Look at my Avatar. The poured concrete piles go down below the frost zone.

[jderek77]

Re: Cold climate foundations

That's an idea worth considering! Thanks.

[Neil2]

Re: Cold climate foundations

Easy to do. I just dug down 4 feet with an ordinary hand held post hole digger. Put in a couple of 3/8 rebar, filled with concrete to about 6 inches of the surface. A second pour, from there up to the bottom of the structural slab I used 7 inch diameter "sonotube" cardboard tube forms - available at any builder supply.

[car1gil]

Re: Cold climate foundations

Hi Neil,
I'm about to start my "big" project, I live in the Chicagoland area (it's cold in the winter..) and I saw your avatar, quite interesting the use of sonotube. No foundation slab needed as per Pompei plans? Are 7" diameter enough? I'm planning on building a 36" oven. Your insight and advice is appreciated!