I am going to increase my growing space this summer. Our land was filled (clay, asphalt concrete..) over and old swamp. It is highly compacted with 5 cm of topsoil. My main vegetable garden like a big bathtub and then filled in the huegelculture style. I works, but it was so much work, backbreaking that I will not ever do this again (I spare you the details). My first approach to extend the growing area was in form of huegelkultur bed but on the top of the existing "soil". It failed because it did not retain the water at all. And after removing some of the material it does nothing to the soil underneath. If I would try sheet mulching it would turn our similar, high runoff and not turning the soil underneath in real soil. So my plan is to either doing sheet mulch but using old roofing sheets (cheap) to hold enough mass in place, or I get someone to rip the soil deeply and then do sheet mulching on the top of it after getting rid of all the stones, concrete pavers etc. But who should I ask? We are not a agricultural area were tractors and implements are available. I could do Holzers method too, getting drenches dug out with a machine, which is logistically kind of difficult because you have strips of beds and in between the much narrower pathways.