Retaining wall construction advice
I want to build a 24" retaining wall, about 40' long, as cheap as possible. Advice needed please!
The grade at my house is about 30" above the grade at my property line, which is about 8-10 feet away. This means there's quite a bit of slope.
I want to fill this in to have a relatively level platform for parking trailers, RV's, etc. I will have to build a retaining wall near the property line to accomplish this. The height will range from zero to 24". Since this wall will not be visible to anyone (hidden by a fence, to be built just inches away), appearance is not a factor - only cost and longevity.
So my options are:
1) 6x6 timbers (pressure treated?), supported by wood posts sunk 3-4 feet in the ground?
2) railroad ties, supported the same way
3) steel, supported the same way (or perhaps with concrete and galvanized fence poles).
I'm leaning towards the steel plate. I have access to the steel cheap, I just don't know the required dimensions. Obviously it would have to be 30-36" wide (some buried), but what about thickness? Would 3/16" work or would I have to go heavier? Heavier might be a better option, maybe I could space the posts wider apart, or is there some standard distance to use with a wall this height?