RatRibs73 wrote:
Cheers,

Whats ply membrane, celotex and AI tape. Time may be a problem with
this solution. Plasterer is coming round Thursday.


Celotex is a stiff polyisocyanurate foam board with foil on both sides.
Its rigid, its easily cut and it has twice the insulation properties of
anything else. You wedge it between timber studwork, and use aluminium
tape over it all to create a water and draught proof seal.

Ply membrane is a typo. damp proof membrane - usually polythene.


Is the cost of doing this worth it?


Absolutely. Turns chilly rooms into cosy rooms.