Sands may be prone to frost heave, particularly fine sands. Hazards with silts are as per sand. Prone to shrinkage and swelling by vegetation. Firm clay can be moulded with finger pressure whereas stiff clay cannot. Prone to long-term settlement by consolidation and sulphate bearing clay will attack O.P. cement.
Hard clay is brittle and tough.
Prone to offer poor drainage. Very low bearing capacity, large settlement by compressibility - will require specialist foundations. Prone to frost heave when exposed and swallow holes. Fill or made ground Consists of miscellaneous material - rubble, glass, waste etc. To be avoided unless compacted in very thin layers.