Why is extra drywall never added inside the framework?

[bygges]

I have installed double plasterboard on all the interior walls of the house for better sound insulation and stiffer walls.

A thought that has come up, why don't we glue plasterboards on the inside of wall plaster to save the centimeters that double plaster takes up from the room? You probably won't get the torsional stiffness, but the sound insulation should be about the same, better than mineral wool, right? You could also put a simple frame inside a stud compartment to screw the plasterboard into the inside of the wall.

 

[AndersS]

It is common to install OSB, which is also good for screwing/mounting, as the first wall board and then drywall.

 

[useless]

The only reason is that it takes too long. If there were panels of the right dimensions to fit inside the studs, it might have been different, but no regular construction worker has the time to cut every panel to make them fit.