My house is built on the side of a hill on top of a rock formation and the front wall of my bedroom sits on a shale outcrop that runs at right angles to the wall, with parts of the reef protruding through the wall on the inside. These particular rock formations are part of a crater structure caused by one of the largest and oldest known meteorite strikes on the planet, called the Vredefort catastrophe - I am literally living on part of the crater rim, which appeals to my sense of my life.
When I first moved in, I noticed that when it rained heavily, water started flowing through the wall at the junction of wall and floor. On one occasion, I was up half the night bailing water off the floor with the dustpan and a bucket. I removed around 20 litres of water and when I mentioned this to others, the response was "Get goldfish!". I started calling it The Water Feature and I was unamused as it was impossible to say whether the water flow was caused by groundwater as the water table rose as a result of the rainfall - a serious problem - or whether it was simply water flowing up against the wall and leaking through at the bottom.
The only way to find out what was causing the flow was to prevent rainwater flowing up against the wall and see if that solved the problem. If it didn't, it would mean that I had a rising groundwater situation, which would not be fixable. A rock garden had been made on the shale reef against the wall so I had to remove the plants and soil and a layer of rocks and concrete until the bedrock was exposed and throw a layer of concrete with a waterproof additive up against the wall that would create a channel for water to flow straight into the drain instead of pooling in the rocks.
Once a clean trench was made, I had to seal the wall
Then it was time to throw concrete and create a slight slope away from the wall and wait and see what happened the next time it rained.
The floor remained dry after the next heavy rains and I was immensely relieved: I could continue using the bedroom and there was no need to make an indoor koi pond!
Next episode: half-baked greywater solutions