I am in the process of building a Koi pond and was wondering about the best material to use for backfilling against clay soil.
The pond will be block built (laid flat-faced to give 9" thick walls all around). The norm is to back fill the first foot of the excavation with concrete and then use stone dust to back fill the rest. The foundation slab is approx 8" of reinforced concrete.
Apart from the difficulty of obtaining large amounts of stone dust in my area, I would go with this but maybe the group has some better ideas?
Cheers!
Jeff To email me just take the MICK out of my addy!