I do not work in the trade, so please excuse this simple question. I would like to remove the grass in our front garden and lay gravel grids down to use it for parking. I read that I need to dig down and create a sub base of about 150mm deep of MOT Type 1, and then lay the gravel grids on top of this. But I have a drain that runs under the front garden, and it looks to be, if not less than, very close to 150mm below the surface.
How can I lay a 150mm sub base with drains like this?
How can I lay a 150mm sub base with drains like this?