I've never been faced with this problem, would guess about a foot, but you might want to check with a professional local contractor. - Bob

We too are having the same question here in DC. The weather was terrible this winter and we're considering some washington dc masonry contractors, but don't know how much it would cost. The house is about 1,200 square feet. Thanks Bob.

As a possible solution to the drought problem we did this. We started using couple of stream hoses to create shower units which kept the ground from shifting and cranking. It worked for us until now.