I think I now will be able to get the quantites required. By the way, the dimentions I gave is one half required. In the middle of footings for the full brick wall, is a line of 2" thick paving slabs that go down 600mm acting as a root barrier.
I really now just have a question as to the aggregate. I myself have crushed down larger sandstone chunks into about 20mm size chunks. Would I mix in with this some smaller chunks? Or just put in 20mm chunks?
Thought your dimensions were a bit quaint. What you are saying now is that you have a 450 wide found that you propose to drop a 600 slab down the middle of to act as root barrier.
Don’t know what book you dug that out from, but root barriers went out the window years ago, and you do not form a root barrier like that.
Have you got any trees adjacent to found?
Sandstone is one of the softest stones available, and we would never put it in a concrete mix. Your choice,
Just one more question. I want to have a straight edge to the footing. I aim to put in the ground, lengths of board. I might need to put in 3 or 4 over the 7m length of the footing. Now, when the footing is set, the idea is to remove sections, one by one, filling in the gap left between the set concrete and the earth after each board section is removed, until all boards are removed.
Would this present any problems? Thanks.
Your shuttering for concrete are the sides of your excavated trench. You do not need any shuttering as only the worms will see side of concrete.
Word of warning. Retaining walls even at 1200 high, if back filled full height require a design consideration in regard to materials being used, width of wall, width of founds for rotation, and excluding any live load above, the lateral thrust of the back fill and possible water content.
Angle of repose of existing ground is also a factor to determine the KN loading of back fill. In our opinion a 450 wide foundation is insufficient for a 1200 high retaining wall. If you are doing this all your self, you would be better to think along the lines of 2400x250x125 oak sleepers. Will last your life out if done correctly/.
oldun