Handcrafted log cabins are very versatile in the type of footings that can be used.
Due to the way that the building is constructed each log acts as its own 'lintel' so a log wall can span between pier footings or strip footings easily. We usually don't exceed spacings of 2000mm.
On a small cabin we generally specify pier footings because they are simple, reasonable inexpensive and work well on both flat and sloping sites.
With a full log home we opt for a full footing and slab, this makes it easier to properly insulate (minimising thermal bridging) and allows for installation of underfloor heating within a screed which is our preferred convection method in a log home.
The depth of the footings will depend upon the ground where it will be sited and the foundations will ultimately have to be passed by a structural engineer. However, as an indication I would work on the following:
400mm wide, 1000mm deep reinforced footing under each log wall. 150mm deep reinforced concrete slab throughout. 3 rows of engineering bricks underneath each log wall to bring logs up to finished floor level. (This allows for insulation, underfloor heating and a liquid screed sub floor finish). Footings are not included in any of our example prices due to the variation from site to site.