There were a couple of high spots on bare rock, which meant that in some places the gravel did not bed down into the normally smooth surface. Therefore, we decided to add a layer of geotextile membrane to help ensure that the polythene sheet was not compromised.
Polythene membrane laid over top of the geotextile, which means we are now ready to start with the steel mesh.
The sheets are ST25SC (3×2.4m sheets of 7mm mesh of 15cm squares), which are half the size of ST25S, so they are more manageable for the two of us to maneuver down into the bottom of the pool.
They are placed on concrete spacers, which raise them up by 40mm. We thought we had made a big mistake with them after the first sheet as every time one of us walked on the mesh it caused the castles to topple over. However, the more sheets that were placed and tied together, the more sturdy it became.
After about 4 or 5 hours, the bottom layer of reinforced steel mesh has been successfully installed. There is still some tying together of the sheets to do, but it is taking shape nicely.
The sheets are tied into each other, ensuring at least a 30cm overlap. There is a much greater overlap in the middle, nearly 1m, as we did not cut the sheets to size. This might end up being overengineered, but this is what everything is based off, so I would prefer to be over cautious at this stage; than regret anything later on.