Señor Chris wrote:

I'm installing an independent ceiling just below the existing one for
sound insulation purposes, so the only load it will carry is an acoustic
quilt above and plasterboard below. Assuming maximum span of 4m and
plasterboard thickness of 25mm, what size joists do I use and at what
spacing ? Is there a generic formula I can use if I vary the span and
plasterboard thickness ?

minimum size will be 2x2, but since you want acoustic insulation
the bigger the better, preferably much bigger than 2x2.


NT