External render over cement board

[Cgas]

Evening,
Is it acceptable to use cement board over a second story external timber wall then render over the cement board ? Or any other alternative options?
It's to replace upvc cladding, but under the cladding is timber?

Tia.

 

[tomfe]

Yes, make sure you have an air gap behind the cement board, there should be one anyway.
You might need planning permission and building regs as you might need to add ewi.