What are you trying to achieve? What will you be doing in the loft?
Andy
Yes to light storage, no to study.
Unless you are going to do a loft conversion, then your cladding would not be used, it would be plaster board.
Andy
As the Pennsylvania Dutch say, “It's for nice.”Whats the point if you only use it for storage.
Andy
A breathable membrane stapled to the rafters? PVC cladding will prevent airflow and a loft without good airflow is an unhealthy loft. In anycase your loft will be freezing in the winter and boiling in the summer. Like a conservatory but worse.