Garage ceiling insulation

[matlob]

Hi

I'm creating a small office and upstairs room in my double garage

The upstairs is going to be fully open with insulation to roof etc

The downstairs is going to be left as a garage apart form one quarter of it is going to be a small office with stairs leading to the top floor

In terms on insulation on the ceiling, do I just insulate above the office area or the entire garage ceiling.

The office area and top floor will be heated but the garage part will just stay as it is (cavity wall)

Thanks in advance of any help

 

[Alastairreid]

Just the garage area needs to be insulated.
Ceiling will need double plaster boarded as well.

 

[frutbunn]

Just the garage area needs to be insulated.
Ceiling will need double plaster boarded as well.

You don't need to double board, you can achieve half hour fire resistance with 12.5mm plasterboard with taped joints.

 

[matlob]

Thanks both.

Its going to have 150mm celotex between joists and it is proving costly : )

May as well do the lot

Thanks