We’ve just had a concrete slab taken up from our garden with a plan to replace part of it with paving and part with a new lawn sown from seed. The contractors have lifted the concrete, and laid a 10cm deep layer of crushed concrete hardcore as part of the base structure for the paving, but have laid this over the entire area rather than just the part we want paved. Our plan had been to prepare the ground for the lawn by bringing in 15cm of top soil, but with the crushed concrete hardcore there is only space for about 8cm of soil if we keep the level as we want. The contractors are telling us that this will be fine, that the hardcore will act as a good base layer for the lawn stop the soil settling too much, and that should drain without any problems. From what I’ve read I have some serious doubts, but am not an expert and thought I’d ask for your thoughts. How bad is the lawn likely to be in only 8cm of soil. I’ve seen lots of write ups about irregular coloured lumpy patches where rubble has been buried under a lawn, but we do at least have a uniform surface. Will it just be a bit drought intolerant, or is it likely to be a real issue? Is the problem fixable by adding a few more cm of soil (we can probably get to 10, but not 15), or is the only option to have all the hardcore dug out? Thanks for your advice.