How to improve drainage in open brick/cement drain extension?
I noticed the high side of my house had no drainage. I began digging a trench for a drain install when I unearthed the original open brick/cement drain. I cleared the drain pipe so began unearthing the length of the drain. The drain finishes at the end of the original dwelling and an extension of 4 ish metres has no drainage. There is evidence of weatherboard and framing rot here so I want to complete the open drain. What do I need (and need to keep in mind) for this project? Am I better off building a different style drainage system that connects to the open drain? Any advice is welcome!
Welcome to the Bunnings Workshop community @doberon. It's sensational to have you join us, and many thanks for your question about garden drainage.
That's a fairly rudimentary drainage channel formed with bricks. If it works and you're a fan of the rustic style, I see no reason why you couldn't continue the length with more bricks. You'll need to source some older bricks, as these days, they typically have holes in them. Alternatively, you could form up the sides, pour concrete for the end section, and create the channel from that, linking the two. I recommend that you check that there's an adequate slope over the length to ensure the water flows freely to the drain.
It would be best to consider removing this system and updating it. First, check to see whether these bricks have been bedded into a concrete base, as this will determine how much work will be involved with removing them. If the bricks are bedded into sand then I'd recommend removing them and replacing them with an Everhard drainage channel on the surface or a buried drain coil beneath it. Both of these can be connected to the existing drain outlet. Whilst we are on the topic, before you start any work, ensure that the drain flows freely as, given its age, it could be filled with tree roots and unusable. If it is, it might be best to run PVC pipe from there back to your main line. Check out this helpful guide: How to install garden drainage.