Cold external solid wall question

[MarkTravis]

I recently purchased a 1920 built end terrance house. The external end wall - which covers the hallway - is very cold (but not damp) so I am thinking about taking the plaster off to the brick and using Gyproc thermaline 27mm plasterboard which, from what I can tell, you simply glue to the brickwork.

Problem: I am on a tight budget in doing this place up and my major DIY weakness is plastering. But when using plasterboad do you really need to plaster?

I noticed in a builders supply store a product made by Gyproc - a sealant - which implies it can be applied to act as a base for painting or wallpapering direct to the plasterboard.

I was thinking of maybe using that followed by thick lining paper, then wall paper..... or am I wishful thinking? or heading for major regrets later?

As a final thought, in using 27mm thick insulated board, what would I do regarding putting up a shelf?

 

[iwaters]

You don't need to plaster but it gives a better finish. You can simply dry line which involves using tappered edge plaster board and skiming/sanding the joints. This is largely what they do in America I learnt recently. Then prime and paint directly on the plasterboard