I want to build a 20x40 barn on my land. The soil is 2 ft of black earth and then goes to grreen clay. How do I prevent the barn from sinking?

Are you in France? You dig to the clay and lay in gravel or build a pole barn.

Are you in France? You dig to the clay and lay in gravel or build a pole barn.

I am in Ontario canada. I heard that the green clay is not really stable enough for structures.

Call around and get bids from contractors for a pole barn, get their opinion. How deep is your frost line?