Following up from my recent post re: dry mix, we parted company with our landscapers over disagreements on this and several other things. I am now planning to finish the work myself, armed with a willing mate, grafter of a wife and this website!
https://ibb.co/QMs9vXS
One of the (many) concerns I have is the finish in the attached picture - no sub-base compression etc. The drop is 400mm and about 3m wide. Originally, I was going to build a tapered double skin 'drystone wall' (held together with hidden mortar) on the concrete pad - 1m high on the low side and 600mm high on the paved side. Wall is 500mm wide at bottom and 350mm at top - capped with coping stones. But as this is a retaining wall I'm concerned this may not hold the weight behind it.
I see I have two options. My preferred one is the double skin drystone wall, backfilled with pea shingle, adding in the geo textile membrane and land drain at bottom etc per the retaining wall section on the main site (no need for copper pipes though through the wall?). Tied together with bigger blocks across both skins (especially at the bottom) tying the 2 skins together. An alternative is to concrete block the back side of the wall as the first skin - again backfilled with pea shingle etc - and face it with the nice drystone blocks as the second skin. Probably some wall ties in place to bond the two skins and copper pipe through the concrete into the void in the middle (as the blocks wont be watertight).
Is there a preferred way? Also, I assume putting concrete as backfill would be sacrilege as it just adds to the weight behind the wall, but am wondering if this could help strengthen the structure?
I hope this all makes sense. Any advice appreciated as always - thanks Ian