Expert: Bruce E. Johnson - 7/5/2010

Question
Hi,i am wanting to build an ornamental wall in the garden made of aerated blocks size 1mtr wide x 2mtr high double thickness,how deep and how would you recommend i did the footings.
regards
carol

Answer
Hi caroljacks, for a wall like this a footing 60 cms wide and 30 cms deep should be sufficient if the soil is capable of being compacted (not soft and loamy)..if the soil is soft and loamy you may need to dig it deeper to cut through the topsoil and get to a more solid base.  I would install two reinforcing bars (13mm minimum x the length of the footing) horizontally in the concrete at least 12 cms above the bottom of the footing. Since you are installing the block on their side it will be hard to do any vertical reinforcing steel but if the footing is installed level you should be okay considering you are making it two blocks deep.  I hope this information helps, feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com