I’m having a wall re-plastered (i’ve hacked it back to the brick-work) and want to add some insulation.

What are my options (or best option)

– Im thinking of either battening to create an (insulated cavity) before lining with board & having it skimmed

– fixing thermal plasterboard straight to the wall & having that skimmed.

The room is narrow (~1550mm) so the thinnest solution possible would be best,

Kingspan (50-75mm?) followed by plasterboard, you could go for adhesive or plug and screw it on, but unless you went for insulation plugs that could lead to cold bridging at the screw/washer. Foil tape the joints of the Kingspan to maintain a vapour barrier (ie keep moisture room-side). If you wanted to put a pre-bonded board on, look at Kingspan Kooltherm k17 (adhesive) or k18 (mechanical fixings). Is it ground floor? If so any options to insulate floor now? I’ve just put fibreglass between floor joists and it’s made a big difference to suspended wooden floor, partly through draught reduction though. Fill all the gaps!

groundfloor, but concrete, so no insulating to be done.