How to attach wooden post to the side of a concrete retaining wall?

[Mctram]

What is the best way to attach a 2.4m, 90mm x 90mm fence post to the side of a concrete retaining wall, 1m high?  The post is one of several to support a frame to which I want to attach screening panels.

[EricL]

Hello @Mctram

Welcome to the Bunnings Workshop community. It's brilliant to have you join us, and thank you for sharing your question about mounting a wooden post to your retaining wall.

Before I make any recommendations, would it be possible for you to post a few photos of the concrete retaining wall? This will give our members a chance to assess the condition of the concrete wall. We can then make recommendations on how to proceed.

You will have to test the wall and see if it is mortar filled or hollow. How old is the retaining wall? Is the retaining wall holding on to a great deal of weight? If it looks like the wall is not as strong as it looks you might have to consider burying an independent post for your screening panels.

We look forward to seeing the pictures of your retaining wall.

Eric

[Mctram]

[Mctram]

Hi Eric,

I have uploaded a couple of images. My idea was to sit the posts on firm earth (clay if I can get down that far) and attach them to the retaining wall both for support and alignment.  The property boundary fence is visible.  It would be very difficult to dig a normal post hole but will be able to get down around 30cm.

[EricL]

HI @Mctram

Thanks for posting those photos of your retaining wall. I suggest a combination of Dunnings 60 x 60 x 35mm M10 Galvanised Angle Bracket in combination with a Zenith M10 x 75mm Hot Dipped Galvanised Hex Head Bolt And Nut you'll need to adjust bolt length depending on how thick the concrete sleeper is.

For the bottom part, I recommend using Ramset 300ml Chemset UltraFix Plus along with Ramset anchor studs. I propose drilling through the concrete sleeper and attaching the top part with the nut and bolt and using the Chemset UltrFix for the bottom of the post. You then use a Zenith M10 x 120mm Hot Dipped Galvanised Hex Head Bolt And Nut to hold the timber post between the two angle brackets. Please note that excessive weight applied to the retaining wall will have a negative effect on its balance.

I've placed an example below of what it might look like. 

If you have any other questions we can help with, please let us know.

Eric