3 layer walls but 2 ceiling? is it worth it?

just a small question. My room will have 2 layers of 12.5mm plasterbaord with green glue... I am wondering if it is worth adding a 3rd layer JUST on the walls but not on the ceiling but is that a waste of time because the "extra" sound stopped could get out the ceiling anyway?? I could go with 3 on the ceiling but would need to have check if it could take the extra weight... Cheers Geoff

I would imagine it will help ... some. The roof and attic above will act in some regards to absorb some sound. But probably not as much as the 3rd layer. It is really up to you as to whether the doors / windows and other areas are up to the sound blocking level of the added mass of the 3rd layer. They (doors / windows) may leak like crazy to which the added mass is useless. Tom