I have a home built in the 40's. The kitchen wall where I want to place the shelf/support is an exterior wall. The wall is rock lath about and is an inch thick with the plaster. The rock lath on the exterior walls is not attched to 2x4s. It is connected to ~2x1 wood strips nailed to the brick or cinder block at standard intervals. The question is: Do I need to screw the shelf supports to the 2x1 strips behind the wall, OR the brick or cinder block on the other side of strips? It is difficult to drill into the brick and it is hard to tell if it is brick or cinder block behind the wall because I've found both mixed with each other on another project.
I am assuming it is not a good idea to just use the wall for support.
If any one has experience with this type of construction I would appreciate the advice.