I checked back on your last questions - the impression is given that the topsoil mentioned was for putting in a newly built raised bed, doesn't mention that you want a new lawn or topsoil underneath it anywhere. You do mention, however, that your lawn isn't currently very good and you suspect 'its built in a gravel pit'. I'm sure you don't mean its actually a gravel pit, but it certainly sounds as if you have some issues with buried debris underneath the existing lawn. Unfortunately, spreading topsoil over the old lawn with a layer of weed membrane beneath isn't a good choice - unless your topsoil is going to be a 4 inches deep all over. Buying in topsoil is a risky business at best, it's often full of weed seeds, some of which are pernicious ones. And even then, if there are issues with buried debris with the current lawn, you'll have the same problems again within two years. The best way to do it is to lift what's there and dig over, removing any rubble and debris, then levelling off ready to receive new turf. I know you're not very mobile, so not sure if you are able to manage this.

Hi Bamboo.Thanks for your response to my last question,Sorry for not being very clear on what i am trying to do.At the moment i have a back garden that is grassed,Not very good as a lawn but having said that it suits at this time as myself and grandkids use it for replica r/c tank battles.I have had built two triangle shaped beds with path between them,They were built on section of lawn in corner of 6ft wood fence and have some grass still there.My hope is that i can cover grass with membrane and then put 12ins of soil on top(my beds are 1ft deep)will this work.The ground i have is unworkable my son in law dug down as deep as two feet in several places and did not get through rubble(needs a JCB i think).My garden is very boring so built beds hoping to put some colour in my garden. Again i am sorry for the confusion i caused you and hope i have made it a little clearer on what i am trying to do.Thanks again for your help....Cheers

Am i right in saying the topsoil is for the two triangular beds ? if so then it should work but as regards plantings then it will be limited, due to soil depth, large shrubs would stuggle here, but smallish plants with small root systems would be ok, or you could use the beds for summer/winter bedding, or incorporate some small perrenials, regarding topsoil, look for a supplier that sells screened top soil or try useing Rowlawn they sell decent topsoil in ton bags, julien.

Well that's a relief, sorry for the misunderstanding. Julien's right, at that depth you can only plant small things. I'm not even sure you'll need weed membrane over the turf if its covered with a foot of soil, that should kill off the grass and disable it from growing through. You could use the membrane, but if you did, any plants in your beds really are restricted to just a foot deep - without it, as the turf breaks down, they may just be able to penetrate into it so you may be able to grow deeper rooting, larger plants. Shame the grass wasn't lifted off - I'd get a half moon edger, cut up any turf you can see into small manageable sections, and lift it out, leaving just bare soil/rubble beneath, then add the topsoil mix.