Retaining wall 10m x 1m (L-shaped)

Hi Gareth, Any retaining wall needs to firstly sit on a good foundation not only reasonably deep but also wide to allow a good footprint. If you can visualise the wall once built and its retaining, the pressure from behind will want to push it forward, by having a wider footing than the wall then this provide a great deal more support and stability than a footing thats the same width. Secondly the wall for 1m high would be fine built with concrete blocks laid on their side giving a witdh of 9" (225mm) it is also a good idea to build pillars into the wall on flats so there is 18" square pillars running through the wall, with the L section will add alot of strength also. Dont forget to add in weep holes into the wall for water to run through, these can be added into the wall as its being built - 50mm diameter pipe should be fine. Directly behind the wall you want to back fill with hardcore and clean stone - 20mm in size, again this is to add for drainage and prevent the build of pressure on the back of the wall. In the ideal world you would lay geotex 1000 first behind the wall then fill with gravel and cover it over the top with geotex, this will prevent soil contamination in the stone which in turn clogs up the drainage. I would recommend getting a concrete company to deliver Gen 3 mix, it will be far stronger than mixing yourself and a lot less work! 11m footing, 300mm deep and 600mm wide ( giving 150mm each side of the wall ) you would need 1.98 cubic meters. If you require further info please dont hesitate to contact us, Regards Henry HJG Contracting Ltd