posted 8 years ago
I think in your location you would be okay. I have never been to the UK, but have been to Ireland and there (not so far away) there are legions of houses built on stone since your frost line (if any) is rather shallow. Here in Maine, stone foundations like that you describe were teh undoing of many houses built in the 1800's.
Frozen soil expands by 9%.
Period.
It does not matter if there is a dollhouse above it or a McMansion, it will move. It has to simply by the laws of nature. It is possible to build on stone, but it requires getting all the water out from under the rock, and this is prudent in any situation. Houses like dry feet (foundations) and a hat (well covered roof). You can find a lot of information on "rubble filled foundations", or "french drains", but if that water is drained off, and thus the soil has nothing to freeze, nothing moves. I would look into that anyway, but if you have lots of rock underneath, and severe compaction, then you might not have an option as digging sounds problematic.