Hi @Lew1,
A warm welcome to the Bunnings Workshop community and thank you for your question.
It's not typically recommended to rely on glue alone to attach cement sheeting to a substructure.
The method of attachment can vary between materials, and you should always check the manufacturer's installation guide, but typically, you would use fibre cement screws through the old sheeting into the studs behind.
Let me know if you have any further questions.
Jacob
