Partial garage conversion - dividing wall between new room and remaining garage

[_me_]

I'm currently planning a partial garage conversion. The current garage is integral and is a double size. The plan is to use the back two-thirds of the garage as the converted space with the window on the side elevation. The front third of the garage will stay as non-habitable and be used as a workshop with the existing garage doors retained.

There will therefore be a dividing wall between the workshop and the converted space which will be within the existing garage space. I don't plan on having an internal door within this wall so access to the workshop will be external only. I was hoping for a bit of advice on the best way to build this dividing wall.

My thoughts are that an insulated stud wall which is fire boarded on the workshop side and 2x 12.5mm plasterboard on the habitable side will be simplest. What I'm not sure on is what insulation would be required / recommended to use? I was thinking 100mm stud wall with 100mm Kingspan between studs, but would that be sufficient?

Any thoughts / ideas are welcome.

 

[John D v2.0]

Plasterboard sounds ok.
Insulation wise also sounds about right but you can do the calcs on the insulation makers web site and submit to building control for approval.
Be aware 4 inch timer for stud walls is about 95mm so your insulation may not fit easily.

 

[_me_]

Thanks John, appreciate that. Will have a look on the celotex/ kingspan websites.