Solid walls are always the best surface to apply concrete screed. It can also be applied on a dry partition wall, but only if it’s made of the thicker and heavier calcium silicate board, says Dess Chew of Three-D Conceptwerke. Still, if you’re mounting something on this wall, make sure that you use the right mounting plug to prevent crack lines from appearing when the plug is hammered in.
Crack lines will also appear as a result of temperature changes, so it doesn’t matter if the screeding is done on a dry or solid wall. If the concrete screed surface is near a window and exposed to various temperature changes, there is a greater possibility of crack lines forming over time, explains Dess.