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1m retaining wall - advice please

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I am currently in the process of landscaping the garden and a complete newbie to this all.  The garden requires a retaining wall and I wanted to check my plans for it.

REQUIREMENT : 1m high retaining wall to hold back a slopped garden

DESIGN : The wall will be built to start at the garage wall, 1m out parallel with the house then 1m away from the house forming an L shape
FOOTINGS : Trench 40cm wide by 40cm deep 
CONSTRUCTION : Plan to fill the trench with concrete at 20cm deep, full width (40cm) with rebar places throughout.  Using 7N solid concrete blocks (100mm) laid on their side throughout giving 1 1/2 blocks under the ground level.  I plan to place shingle against the wall, all the way up, wrapped in a fabric waterproof membrane before back filling with the earth from the excavation

FINISH : I will be rendering the wall after it's all done


My question is will this be sufficient footings and a decent structure to retain the garden.  Also when back filling with the excavation earth will it will be strong enough to support a mini digger push it back in place and compacting it?


Thanks in advance



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Basically no. A single skin block wall won't hold back that amount of pressure. 

You want the wall to have steps so the earth its holding back rests on these and stops it toppling over. So your bottom course would be 450mm wide then steps in to 330mm for another course. Then 1 course at 215mm and a single row of 215mm then a block on its edge, 100mm wide. This will give you a height of 1m. 

You backfill with clean gravel with some sort of drainage channel or weep holes in the block work. The membrane sits on the ledges of the steps and helps to hold the wall in place. 

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