Good afternoon,
I'm building a small raised patio area in the back garden. It'll be raised above the ground level using 200x100 sleepers in a picture-frame arrangement. The void will then be filled and eventually flagged on top.
I have removed the turf from the area which has taken the whole area down by approx 50mm. I will be laying the sleepers on their 100mm side and fastening each one to a series of 100mm timber fence posts concreted into the ground.
My question is: As I am aiming for a minimum of 100mm sub-base, can this just be poured and compacted on-top of the soil level I am at now, or will I need to dig down further? I'm just conscious of that fact that as it stands now I'll have a void of 200mm to fill to bring the finished patio flags level with the top of the sleepers.
Thanks in advance!