Mechanically affix K118 or similar insulated plasterboard to solid brick wall

[MisterBoy]

I want to add internal insulation to solid-brick walls. They are plastered and papered in good condition and I don't really want to strip that off. I want to minimise the depth added so I don't want to batten on top of PIR boards - thinking 40-50mm PIR (based on rough U value calcs). Insulated plasterboard seems a good option mechanically fixed directly onto the existing wall and then skimmed.

How would you recommend doing the fixing though, in terms of fixings per sheet and any product recommendations? My hope is to do the install myself and get a plasterer to do the skim, for us to paint.

A quick google turned up these clever looking things which would cope with up to 100mm boards I think, but I've never heard of them before: https://www.twistfix.co.uk/insulated-plasterboard-fixings

 

[Mr Chibs]

I haven't used those.

But you could also use wedi washers, (long screws and rawl plugs) or just concrete screws straight into your brickwork.

6-8 fittings per sheet should be plenty.

 

[MisterBoy]

How would you find the holes accurately for the rawl plugs? Put the board in position and pre-drill all the way into the wall, remove to fit the rawls, and put back? Fixings which avoid the need seem to be a winner - I think concrete screw is the fixing I didn't know about for this job.

 

[catlad]

You are supposed to remove wallpaper before doing this to reduce the chance of mould.