Hi, we're at a bit of a loss on the best approach to a foundation for our patio. We had a new patio laid in our garden around 6 years ago that is now uneven due to heave. The soil is clay and the garden is surrounded by oak trees.
Someone has suggested a concrete raft foundation, someone else has suggested ground screws with a frame and someone else has said all that's required is a deeper concrete sub-base.
I don't want to throw away more money on the patio by having it done incorrectly a second time.
Advice very much appreciated!