# Forum Home Renovation Retaining Walls  Fence/Retaining Wall Construction

## SLUGGO33X

I'm in the process of designing a new fence/retaining wall to replace a collapsed wall on the boundary separating my neighbour and I and just wanted to run some ideas by some more knowledgeable folk. 
The previous wall's foundations have shifted and the wall itself is starting to collapse due to two large trees. The trees have since been removed. My natural ground level is approx 500mm higher than my neighbours. 
In an ideal world, i'd use boral 20.01 (390x190x190) concrete form blocks lined with steel and core filled with concrete, but this is going to be pretty expensive and my neighbour's budget doesn't stretch that far. 
To try and keeps costs to a minimum, i'm thinking of using boral 10.01 (390x190x90) concrete blocks which i can get at approx $1.20 per block. 
The wall is 16m long, and the retaining wall needs to be 800 high. The remaining height is purely cosmetic. 
I planning on laying new footings, and using 2 blocks wide for the retaining wall, and then single for the remainder. 
Here is a rough sketch...   
I think i need approx 450 blocks @ $540, and 1.5m3 of concrete for the footings @$300. I just need to budget for an excavator and bricky. 
Questions: 
1. If i backfill with aggregate and use ag-pipe etc, will the double block retaining wall stand the test of time?
2. Are 300x300  footings sufficient?
3. Have i missed anything? Suggestions, comments?

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## seriph1

wish I could help! Will be watching if/when someone does though  :Biggrin:

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