Insulating bay window roof.

[MisterG81]

Im having the front rooms of the house re plastered next week so i am making any improvements i can while i have the chance.

the upper-bay itself is single-skin brick/timber and tile fronted.
The plasterer is going to build-out a timber frame, and ill use kingspan or similar to insulate between the frame, and insulated plasterboard to finish.

For the roof area - will 50mm kingspan between the batons be sufficient and leave the eaves area above untouched? or should i be packing the area with rockwool?



Any comments or suggestions welcome.

 

[oldbutnotdead]

Is that a pitched roof to the bay? And is there any ventilation in the void?
You should probably maintain an air gap under the felt through to the eaves- if you can get the usual roof thickness (250mm rockwool) in there without compromising the airflow under the eaves then do it (50mm solid is about the same as 100mm rockwool so you can save a bit of height there)

 

[MisterG81]

The bay itself is flat roof the gap is the eaves of the house roof. I'm thinking 50mm kingspan like this will be enough? That will maintain airflow round the eaves yet still provide useful insulation in the room?