1.2m plasterboard, but 1.22m joists!!!

[Roberto2019]

Have I screwed up here?

Just bought all my plasterboard to redo my ceiling, currently looking at bare joists following an extension build.

The house is 1950's so joists are 16" apart, which means my standard 1200 x 2400 boards are just short in both directions.... which is very annoying.

Is there a good way of getting around this, or do I need to just cut them shorter and accept I am going to have a load of wastage?

Incidentally I notice that sheets of plywood are sold as 1.22m, which would match my joists...? Why is that??

TIA

 

[kp00110]

Sister some lengths of batten along the joist to catch edges ?

 

[noseall]

Incidentally I notice that sheets of plywood are sold as 1.22m, which would match my joists...? Why is that??

TIA

USA/Canada spec' lumber v's European plasterboard.