hi guys, just now i take my office ceilling down, i discovered that it is about 2cm-3cm thick and very strong. i knock knock it also no problem.

last time i do the similar ceiling certain area in my home, but the ceiling board is so thin and fragile, easily pecah if some strength applied. its thickness about 0.5cm only. feel like chalk/kapur when pecah.

is it low low quality product? usually if change how much per piece? thanks