fred coughed up some electrons that declared:


When putting celotex between rafters it is even more important to
exclude water. If it creeps into the unventilated trough formed by the
celotex, between the rafters, it wont be able to escape and we all know
where that leads. This is the case even if the area above the celotex is
ventilated.

Definitely repair the sarking[1].

Since you put it like that, it makes sense.

I'll get some spare and work it into the hole so the overlaps are more or
less right, then tape it up with some duct tape.

Cheers

Tim