If you intend to use your room in the roof for workspace, then you will benefit from insulating the walls, roof and floor. If it is to be residential then you will need to satisfy the Building Regulation requirements.

High-performance Celotex insulation board complies with the thermal requirements of building regulations It is lightweight, durable and easy to install.

Thermal Conductivity: 0.022 W/mK
Finish: Foil Faced
Usage: Floors, walls and roofs

Celotex insulation board

To protect from outside noise (and vice-versa) and noise between room spaces, you may benefit from fitting Rockwool.

ROCKWOOL FLEXI® is multi-use, dual purpose thermal & acoustic insulation with a unique flexible edge along one side. This ensures a good fit with the supporting framework for optimum effectiveness.

At 140 mm thickness, ROCKWOOL Flexi™ has a thermal conductivity of 0.035W/mK. Adjustments to timber sizes and/or additional insulation may be needed to meet Building Regulation requirements.

Rockwool Insulation
Heat Loss