Data sheet 1 right shows a selection of suggested bases, We can’t stress how important it is to prepare the sub base correctly. After all you wouldn’t build a house on a poor foundation or no foundation at all would you? You’d be amazed how many buildings we deliver, only to see the customer hasn’t even cleared the area never mind prepared it.
If the selected area is turf (grass) this should be removed, depending on the sub soil you may need to add hardcore to stabilize it, an anti weed membrane can be added