Boards with holes in them?

[Maxal]

There are apparently gypsum boards with square holes in them (supposed to build an acoustic ceiling), does anyone know what I mean and where I can get them? Also, suggestions for other boards with pre-drilled holes and reasonably torsionally stiff that would be suitable for a ceiling are gratefully received...

 

[Schwingen]

Apparently, there are plasterboards with square holes in them

Do you mean Gyptone Quattro???

 

[Maxal]

Ah, perfect, I'll take a closer look at that. Thanks!