How to replace supporting 1.2m timber retaining wall?

jenyushaw

Hi all,

This “garden bed” portion of our retaining wall is in a disgraceful condition. This is a 1.2m tall and 10m wide second level of a retaining wall. It looks like the fence behind the retaining wall is in good shape above ground, so we are hoping to DIY the reconstruction of the garden bed portion (fully understanding that we are not engineers). 
I plan on removing some bricks and extending the wall out by 20cm before digging holes and installing galvanised steel beems and concrete sleepers. 
I’m eventually planning on removing the rotten wood before filling with appropriate filler. 
My questions for the forum is two fold - 1) Is this job structurally complex and just needs a professional? And 2) If I was to extend the retaining wall successfully, would I be able to remove the rotten wood without risking the integrity of the fence behind? 

Many thanks in advance, 

MitchellMc

Welcome to the Bunnings Workshop community @jenyushaw. It's brilliant to have you join us, and many thanks for your question about repairing a retaining wall.

I'd consult with some professionals on this one as it's complex. That's a bit of a precarious setup to begin with, having the higher retaining walls posts down into the lower retaining wall. Now that the lower retaining wall is compromised all of it could come down.

I would advise you not to touch it. Consult with the neighbour on the other side of the fence, as their retaining wall is only held up by this one. Contact a professional fairly briskly, and danger tape off the area so no one walks in front of the wall, especially in the worst bit.

Please let me know if you have any questions.

Mitchell