I'm in the initial stages of planing a structure build, I say structure because what I'm really looking to build is an off grid ( no running water or sewer for staters ) vacation cabin on apiece of property I have. It's in farm country and I want it to bland in with the surroundings so I'm thinking of going barn style. I'm also interested in a post an beam type construction, or perhaps some post and beam hybrid.

The property is slightly sloped, and in the spring is quite wet, as the water table is not far below the surface. In addition it's in zone 6 so it gets quite cold in the winter. According the soil survey, the soil is "ontiora silt loam" but it seems to me that the soil probably has a bit higher clay content then that soil survey would lead one to believe.

Some of the neighbors build on peer foundations, but had some issues because of heaving ( perhaps they did not go deep enough ). I'm looking for some recommendations on what type of foundation to build on, I'm contemplating some type of radiant heat floor that is driven by passive solar ( just to keep the space above freezing ) and then supplemented by a wood or pellet stove. I've read about slab foundations, but I've also read about Raft foundations, although the material cost seems significantly more.

Cost is a factor, but I'm going to try and do as much of the prep work my self as possible, so if it comes down to material costs of a few 1000 here or there, I would rather go with the better option.

2 Answers 2


You have two choices (see sketch) - 1) Continuous Footing (left), and 2) Full Basement (right)

The pier or pile foundation is not ideal for your location, since soil below the slab and pile cap will get freeze when cold hits, and thaw when the ground getting warm, which will exert a tremendous amount of uplift on the structure above. The pile needs to be friction type or with a bell if used.

For the continuous foundation, the inner face insulation is necessary to prevent the enclosed soil from freezing. Your local building code (NY Residential Code) has the requirement and some details, and you shall consult with the supplier/manufacturer for the best practice. Insulation is optional for the basement walls.

Both choices are reinforced concrete construction. You shall engage a structural engineer for design.

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  • For upstate NY, the frost depth is arranged from 42" - 48" or more. Check with the local building code official before construction.

  • You shall replace the soil below the continuous footing with compact fill, as silty loam is not an ideal construction material.

  • Assume the groundwater can reach the low side ground elevation for structural design.


You have several foundation issues to consider: 1) deep enough to eliminate frost/thaw heaving, 2) deep enough to insure stability, 3) deep enough to resist seismic activity,

1) There are lots of charts that will tell you the minimum depth required to reach the frost line. A slab on grade is NOT acceptable, unless it’s structural and tied to a “deep” structural foundation system.

2) In order to find stable soil, you’ll need to go very deep. (Where I live we use piles or piers and go 70’ deep.) We use a geotechnical report performed by a geotechnical engineer. They drill over 100’ deep and take samples. Those samples are analyzed and they produce a report that allows us to recommend the correct foundation.

3) If you live in a seismically active area, you’ll need to consider a “deep” foundation system too. If so, you’ll need an architect or structural (not civil) engineer.

Your neighbors that build on piers, but still have problems, probably did not account for axial load and it settled rather than heaved.

Depending on your soil conditions, you may need DRIVEN piles rather than POURED piles (piers). I’d talk to a local pile driving company and see what their costs are for various pile and pier foundation systems.

Also, because you mention fluctuation in water-table, you’ll need to account for insect infestation.

  • I should add I'm in upstate NY, your right, the frost depths are all over the place, butI've also read that creating a slab foundation with an insulated shield is also an option
    – user379468
    Sep 11, 2018 at 16:15

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