1920's - 1930's concrete retaining wall facade
All over San Francisco in the "normal neighborhoods" houses were build with concrete retaining walls. Mostly they were 3 to 6 foot high in the fronts facing the street-sidewalks. The facades had a molded concrete look that mimicked large blocks of stone with a 1 to 2 inch flat framed edge then a "screw driver" sized line as if the edge of the blocks had they been real.
What I am trying to find out is how was this done. Was a mold used when the concrete was poured or was a mortar mixed up and applied over a concrete retaining wall.
We wish to re-create this process and many concrete folks we have contacted are clueless.
Anyone who has a though or a lead please let me know.