We have decided to start building the swimming lane first before the main house, because we had a serious problem with rain water this week, when we had very heavy rain falls gushing off the neighbours workshop and garage grounds.
So we are building a steel reinforced heavy duty block wall nearest the fence, this being the back wall of the swimming lane. Then we can rebuild the soil back up again to stabilised the ground so we can repair the fence itself too.
So the foundation is a 100mm thick concrete slab, set at the 9.200metre point (800mm below the nominal ground level), the first part of the wall will be made using 215mm wide concrete hollow blocks with steel 10mm reinforcing bars through all the holes and then ready mix concrete poured into each column to lock everything together.
The back wall is 6 blocks high (215mm each equals 1350mm high including mortar joints), which will put us above our ground level but still 500mm (at least!) below the neighbour’s soil level. For this, we will put another two layers of blocks but only using the narrower (140mm wide) hollow blocks because there is less weight and load of soil and also at this point, there is a “return” channel for the water to flow back down to the beginning and circulate around through the swimming lane. This is our natural filtration system for cleaning the water, using lots of water plants.