Can I literally stick my insulation to the roof boards?

[CotswoldDoItUpper]

So, new replacement roof on the conservatory. No ventilation gap between new roof osb boards and wall (there never was in the first place when it was a polycarbonate roof). Can I just stick my insulation to these boards or do I need a ventilation gap of about 50mm?
 

thanks! 

[Mr Punter]

If there is a door between this and the rest of the house and you have no fixed heating you can do as you like.  If you could have ventilation above the insulation, with a decent clear path it would be better.  Cover the lot in polythene before you add the plasterboard.

[CotswoldDoItUpper]

11 minutes ago, Mr Punter said:

If there is a door between this and the rest of the house and you have no fixed heating you can do as you like.  If you could have ventilation above the insulation, with a decent clear path it would be better.  Cover the lot in polythene before you add the plasterboard.

there is. It might accidentally fall off at some point though….

 

I was more asking about good practice. Do I need to allow air to circulate on the ‘cold’ side of the insulation? Trying to avoid internal damp/condensation. I will be filling the gaps with foam and foil taping over the lot.
 

If I can stick the insulation to the boards I can get 100mm in otherwise I’m limited to 50 between and then 20mm over the internal joists to combat cold bridging….

[CotswoldDoItUpper]

Meant to add that the roof felt is breathable apparently…. 

[Mr Punter]

Are there any battens or are the slates fixed through the felt into the OSB?

[CotswoldDoItUpper]

Slates screwed through the felt into the osb, As per manufacturer instructions (14deg pitch).