Footers or Slab

[tusr18a]

Re: Footers or Slab

I live in Western Michigan and grew up in Central Maine. Not wanting to worry about what Mother Nature might throw my way, I put the full foundation under my oven. Dug down through 4 feet of clay. Poured a 1 foot thick footer to support the walls. Cement block to grade and 4" slab on top of that. Everyone that saw the build told me that I was crazy. I told them that I agreed. I rest well knowing that frost will not likely topple the oven. On top of that, I was able to practice my masonry skills, which were non-existant, while building the block wall that is now hidden under ground.

[forno di Lucca]

Re: Footers or Slab

all great points and a good read as I am having the same dilemma with my layout for my oven build...I was actually talking to an engineer friend of mine and he mentioned a floating slab 16" thick ---he said that for gas stations and garbage bin areas behind your local grocery stores thats all they do......heavily reinforced with re-bar of course and he mentioned adding a couple of inches thicker towards the outside edge.....and 2" of polystyrene insulation underneath!

[dmun]

Re: Footers or Slab

and 2" of polystyrene insulation underneath!

Sounds like frost-protected-shallow-foundations to me. If you can't take the structure down to the frost line, bring the frost line up to the structure.

[BeanAnimal]

Re: Footers or Slab

I have looked at that page several times over the last year or so and similar pages.

This is the applicable image:


But my concern is still the highly plastic and expansive clay soil. It is very tempting to try for a project like this, but I just don't see how it will work due to the poor (total lack of) drainage under the 6" gravel layer that is beneth the foundation.

A parking slab at a filling station and a 6x6 oven are very different

[Neil2]

Re: Footers or Slab

If you go the pier route, do not tie an at grade slab to the piers.

This will not contribute to the bearing strength. In frost susceptible soils in particular, a tied slab will tend to move and put stress on the piers.