Stone foundation with minimal excavation - idea and a question

working on my design for my little cabin and i have a good area in the woods.  i dont want to cut any trees down if i can help it, was wondering if just excavating the topsoil off of the foundation area, building the stone foundation and then backfilling 24'' up the foundation wall would be sufficient.  see attached pic.  there are a number of old Appalachian log homes that seem to be just on stacked stones pretty much level with the mineral soil

code here requires 24'' of cover of any footing.  

thanks!

I would say that you need to dig down to solid subsoil, however far that may be. When it gets compacted enough that it takes real work to dig farther, you are probably good. I would make the footing wider than you normally would for a deep-dug foundation just to ensure that you don't overload the soil bearing capacity.

Filling on a slope to get the required 24" cover sounds like a fine plan. That also has the benefit of ensuring that there is positive surface drainage away from the foundation. You will have to get that fill from somewhere, so it probably makes sense to balance digging down for the footer with the amount of top fill you will need, minimizing transport of earth.

ok thanks.

getting extra dirt isn't an issue, i primarily don't want to bother the roots of all the trees.

Around here the settlers of the 1800,s did that very thing. They dug down 4 feet and then used the dug material to berm up four feet to get an eight foot foundation.

I think in modern times at places that have building codes, you are required to dig down so many inches below frost level whatever that is, Here in Maine it is four feet. But that will vary on where you are building.

Steve makes a good point about the frost line. You'll want to know what that is for your building site, and plan accordingly. Setting a foundation below that point helps prevent the building from heaving and twisting during the annual freeze/thaw cycles. Buried things (like fence posts and foundations) tend to get pushed out of the ground if not sufficiently anchored. Your embankment should help with this, but it would help to find someone know knows more about embankments and their effect on the frost line and structural stability.

Brian Kaller had a very interesting photo on his blog (here - https://restoringmayberry.blogspot.com/2023/02/pub-in-bog-of-allen.html) showing a pub built on a bog in Ireland, that apparently rocks like a boat under the force of soil movement, yet it remains intact and functional. That's an impressive bit of construction engineering, to say the least!

Good luck on your building!

The frost line depends on the current grade level, not the historic level, so adding fill in summer will cause the frost line the next winter to follow the new ground level. If the interior of the foundation is open to wind, the ground level inside is also relevant for the frost line, so you would need to either enclose the foundation to keep it warmish, or berm on the inside too.