New gable walls insulation question

[OvertonPlumber]

Hi we have had our front and back gable built up.
The nature of construction will be 20mm render/100mm concrete blocks/50mm airgap/13mm osb /4x2 studwork/80mm celotex 13mm osb x2/vapour barrier/plasterboard/skim

Now I asked my bricky if he needed 50mm cavity batts, to which he said no.
Just had a conversation with chippy who was here when the building inspector was here and he wanted cavity batts.

Confused. Com

 

[^woody^]

You can't have cavity bat insulation on a timber frame, the frame needs a clear ventilated cavity.

 

[OvertonPlumber]

Forgot to mention we had tyvek stapled onto the face of the osb facing the cavity.

 

[^woody^]

Doesn't matter.