Hi All
I want to raise our patio so it reaches up to the patio doors we had fitted.
We don't want to use decking.

As far as I can work it out, I'll build a retaining wall around the intended
patio area, fill it with rubble and crushed hardcore then lay slabs on top.

It will need to be four or five feet high.

Can anyone recommend the depth of foundations, thickness of the wall (dense
blocks) etc and can I use any of the soil removed for the foundations to
fill inside the raised walls.

Do I need to talk to Building Control or Planning.

Thanks
Roger