By Dannyh
United Kingdom 
I have put 5 tonne of new topsoil in my garden over roughly 40m2 as I’ve raised my garden by approx 4 inches and layed down boards and gone over it with a roller and layed new turf but any pressure put on the lawn and it sinks about about an inch, what is there that I could possibly do to remedy this
13 Apr, 2021
Answers
Just to clarify, do you mean 40 metres square or 40 square meters?
13 Apr, 2021
The soil will naturally settle into place with the rain and traffic. It is not inert. As mentioned you may need to take up the turf again and top off with new soil if necessary. Before you lay the turf again, give the soil a chance to settle again.
13 Apr, 2021
Thanks for your comments, the topsoil and turf has only been down for just over a week and it is an area of 40 meters square
18 Apr, 2021
welcome to GoY. A couple of questions first sorry!
How long did you leave the top soil to settle before you laid the turf? How long has the turf been down?
If the turf has only been down less than a fortnight it can be rolled up again then you will be able to do more rolling and watering of the soil to get it to settle.4" is quite a lot of soil to settle.
see what others suggest.
13 Apr, 2021