# Forum Home Renovation Retaining Walls  Add height to existing concrete retaining wall - some advice required please

## jrmr500

I have a retaining wall out the front. It is a multi-level stepped thing. It is concrete with no cracks and has been there for some time by the looks of it. It is about 500mm thick/deep. I would like to make it higher on the left hand side (up to about 1m) and keep it level across to the right hand side of my block. I have shown this in Green. Another part of the retaining wall should be replaced. In the picture I have included, it is shown in red.  
This red section will need extending up to the height of the green section along the front. I would also like this to be 1m high at the front and run from the front boundary of the property to where my neighbour has their pergola. The stripy posts are representing the current tubular fence attached to the retaining wall. The fence posts are spaced at 3m. I can cut them away or leave the 1st and 5th one as this will be 12m (the length of the green area. 
I had a retaining wall guy come around and he just suggested replacing it all with concrete sleepers at a cost of $320 per sq./m. I worked that out to be about $4500 including disposing of the old wall ($600'ish). 
I don't have $4500 to spend on a retaining wall. I don't see why I couldn't add concrete to the top (with some reo bar inserted into the existing wall) but I can't seem to find anyone who wants to do it. I am in Para Hills South Australia for reference.

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## barney118

A retaining wall is designed from the footings so see if you can obtain plans from the original. Engineer would be your best bet for a couple of hundred bucks for advice. Still this is one of the first questions that need to be answered.  
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## jrmr500

> A retaining wall is designed from the footings so see if you can obtain plans from the original. Engineer would be your best bet for a couple of hundred bucks for advice. Still this is one of the first questions that need to be answered.

   Thanks for the reply. There are no building applications listed for the retaining wall in the title (there are for other things) so I can only assume building approval or advice from an Engineer was never sought.  
I guess I understand that I can't just make the wall higher without understanding how it was constructed in the first place. I would just like to find a person to come out and tell me my options rather than just wanting to build me a new wall that I can't afford at the moment.

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## Marc

When you say concrete, you mean solid poured concrete? Or concrete blocks? Solid concrete sounds bizarre and adding more solid concrete on top is OK for a bunker but too much for a fence wall. 0.5m thick seriously? Building up with concrete blocks is a consideration and wouldn't add too much to the weight unless you go and core fill it. It still needs to be done properly if you want to then have a fence on top. Perhaps core fill and add steel only where the post are. 
Having said that, if the wall is concrete and half a meter thick, and it has not cracked, I think you can build 2 story house on it.

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## Pulse

Most walls under 1m legally don't need an engineer provided they are away from the boundary. A mass gravity poured in situ wall 1 m high by 500m wide is not going anywhere. Make sure reo ties it all together. No fines concrete backfill and drainage helps too.  
Cheers pulse  
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