I am planning on laying a slab as a base for a car standing. My garden level (and the planned top of the slab) is about 300mm lower than the ajoining garden. What should I use as a retaining material along this soil, preferably without having to build a wall?
I've used paving slabs on edge for this problem and they work beautifully. You really should make sure that the depth underground is at least the height above - but once you get the car-standing slabs down to level, their weight will help hold the neighbours soil in place.