insulation advice needed for office, Thanks

[imiami]

Please see picture attached below:
The office was garage converted, it is cold then the other room, I realized the wall(green colour in the picture) was not insulated, It looks pretty simple job, my question: do I need need extra layer or work before I put the insulation board on this green wall? as this insulation is inside of the garage, I guess it should not much damp, as the garage is not as cold/wet as outdoor, am I right?
is this kind of board ok: links from wicks
Many thanks

I am just a diy er and not a professional but kingspan should do the job. I would make a wooden frame on the wall and then fill in the central bit with kingspan. if you are worried about damp then you could leave a small gap of a few cm at the bottom of the wall so that damp can escape but like you say it should be pretty dry. Will only be an issue if there is no damp roof course in the garage.

@imiami I have recently looked into this as a competent DIYer. I was looking at insulated plasterboard because I wanted that finish rather than shiny foil which is how the usual Kingspan type insulation appears. There are different thicknesses with the insulation already attached to the back of the plasterboard.

I have attached this video below by a chap who has done lots of very well researched DIY projects, I think his is the best one for you (there are lots of youtube videos showing the timber framing suggestion above or using a dot and dab method of adhesive, ie Carpenter's Daughter, The Restoration Couple, Charlie DIYte) but Keith, like others, is using a can of foam adhesive that adheres straight to the wall making it so much easier and how we will be doing ours in our integrated garage wall. I hope this helps. Keith has also had issues with his damp course as the drive was built up higher than his DPC and he addresses that in another video.