Our house is mostly plaster board over redwood planks. For the most part, these planks are not fixed to the studs, except at the floor and ceiling. When they are fixed to the studs, it's usually via another board fixed crossways to the redwood planks and studs.

So, the question is: how to fix hanging cabinets to the wall when you can't find the studs?

Knocking doesn't find the studs. Stud finders don't work. A finish nail through the plaster, backing and planks doesn't work (already nailing into a 3/4" plank behind the plasterboard). I have pulled a strip of plasterboard off the reveal the planks, but this still doesn't help find the studs; the nails holding up the plasterboard seem to be randomly spaced!