So, this weekend just gone, I had another successful volunteer weekend. With a good lead up to the weekend, we had a scorching Saturday, and managed to get the materials in place for the french drain, which will serve the purpose of directing any run off away from the walls of the building, and prevent it from building up behind the retaining wall.
The general principle of a french drain is that you sit a perforated pipe in a trench, and cover it with gravel. Any rainwater will then filter down between the gravel, gather in the pipe and drain away. A good website showing how it is done well can be found here: http://www.nachi.org/french-drain-inspection.htm
What made my installation a little more complicated is that I wanted to add in a waterproof membrane to ensure one side of the drain didn’t let any water through to the tyre wall. So I had an installation more like this diagram:
Installing a drain looks so clean and fuss free on other websites, but I found the practicality of it to be much more difficult!
We first out had to measure the membrane, which was 2m high. We rolled it out along the trench line and gave some slack to be sure everything would fit.
With the distance cut, we folded the membrane in half and tucked it down into the dug out trench. Because we were going around corners, and, on the front of the wall especially, the trench was not evenly supported either side, this was a lot more difficult than first imagined!
Finally, we tucked in the pipe and started throwing stones on top to hold it all down. Work on this is currently ongoing, so I’ll post photos when it’s all done!