'Deep' patio needs a lot of hardcore/sub-base...

[Boxa]

Hi everyone, I would be really grateful of some help re a patio I am about to build. I like to think I am a fairly competent DIY’er and have done a block paving and patio before with good results, but this is a bit of a bigger project.
In short, the patio itself is going to be ‘pie slice’ shaped and my main concern/how to question is the hardcore/sub base I need to use in the deep section against the retaining wall (the depth here is approximately 1.2 metres). As you can see by the photo’s I have attached, I have bit of hardcore I can use as sub base, which I was going to break up into approximately half house brick size and smaller (although I appreciate I am going to need a lot more) but from there do I kind of put layers of hard core down interspersed with compacted MOT 1? Or do I do something else?
Also, the retaining wall itself is double skinned (if that is the correct term to use) and I am also thinking about what I should feel the gap between the two retaining walls sand/cement/concrete mix???
I have a couple of questions about the wall itself, but I’ll keep my powder dry for now
Thanks in advance,
Paul

 

[blup]

Proper compaction of the broken bricks and hardcore is key, and the capacity of the wall to act as a retaining wall.

Blup

 

[freddiemercurystwin]

Broken bricks does not make hardcore, well compacted or otherwise. If you were supporting a floor in a house for example, Building Control would not permit you to do any compacted layers beyond about 600mm as they will drop, even with proper hardcore.

 

[Boxa]

Hi Blup & Freddie, thanks for the input, much appreciated.

 

[mrrusty]

Personally I don't think that wall has a hope of retaining what you are planning. I think I would be considering a decking solution rather than sub-base/patio. Or perhaps patio up to a reasonable depth of sub-base with an intermediate retaining wall, and then an arc of decking where it gets higher.

 

[Boxa]

Hi Mr Rusty and thanks for your reply.
I did post the same issue on another forum and the general consensus there agreed with yours. A shame as we had someone in to do the wall and now I'll have to work round what we have.
It's funny you mentioned about the half decking as that was one solution I was thinking of. The other is to build another retaining wall inside of the current one and tie them in.
Decisions, decisions eh...
Thanks again for you reply and always open to further suggestions