I had the drive (140 m2) surface skimmed and 150mm DOT1 laid 2 years ago - to see what level of movement the cars produced. I got about 30mm rutting and tidal waves of DOT1 so I want to use cellular system.
Problem is the ground worker left the DOT1 at 150mm below the DPC with a fall away from the house.
It appears that I could set the drive to 75 mm below DPC if it has a gravel finish next to the wall.
Does this apply for a cellular system - its all gravel finish, sloping away from the house, fully drained by existing functional soakaways?
The top of the MOT is 150mm from the DPC & the cell structure uses 35mm sharp sand and then 40mm for the cells (which are gravel filled) so I'm 25mm high.
I'll dig out and drop the level - doing the proper job.