Membrane or Duplex Plasterboard

[Tin Soldier]

Morning All

 

So I have two options for a continuous vapour control layer to meet building regs - according to the architect anyway

either install a membrane all over and use standard plasterboard

 

or his preferred method of duplex / vapour check plasterboard.

 

 

Difference in cost to me is £700 between the two, plus my time to install the membrane (It's a very large area and high ceilings)

Are there pros and cons to either?

 

 

 A separate question,

My local builders mechants only supplies tapered edge plasterboard, is this an issue when skimming? should I find square edge somewhere else?

[nod]

Duplex all day long

We are hardly ever asked for vapour barriers anymore 

Tapered edge are preferred 

Im not sure why square edge boards are made anymore