How to use blueboard for rendered retaining wall?

lyndal1

I have a substantial amount of retaining to do and I would like to achieve a rendered look to suit my home. I am looking to plant the top of the retaining walls. 

I was thinking of treated timber posts fixed framing for the seat part, fixing blue board back filling with Rock against the back to help with water filtering through and running drainage at the bottom. Then I'd render the blue board for a nice finish.

I'm open to suggestions or ideas and please let me know if I'm completely missed something. I have no retaining wall experience. Photo attached of the look I'm after but without the camping tile 

MitchellMc

Hi @lyndal1. 

I suggest first building your retaining wall/garden bed as a standalone structure. You'll find this step-by-step guide useful: How to build a raised garden bed. Remember to check regulations in your area, as if the structure is retaining soil, then once it hits a certain height, it will need engineering. 

After you've built your retaining wall from sleepers and posts, you can attach a batten frame of H3-treated timber onto its faces and fix your blueboard to the frame.

Framing isn't enough to retain soil/rock on its own and is typically H3-treated, which means it shouldn't contact the soil. You'll need the H4-treated sleepers for retaining purposes. The reason for the framing over the sleepers, which the blueboard attaches to, is that if you fix it directly to the sleepers, you'll get moisture transferring through them and discolouring your render. It will be best to have an air gap between the blueboard and sleepers, and you might also like to look at sealing the rear side of the sheets when attaching them.

I've created the rendering below to help illustrate.

Please let me know if you have any questions.

Mitchell