How to add insulation here

[noseall]

Are they ring shank nails, what gives them a grip better than old nails used for lath.

Not ring shank no. Just galv. But you try and lever the batten off and often the the nails stay put and pull through the batten. I tell the lads when fixing the first eaves batten, never to send the nails home until you are sure. You can end up wrecking the felt too, trying to remove the battens. And then a dodgy nail head will shear and leave the spike behind.

 

[aveatry]

Not ring shank no. Just galv. But you try and lever the batten off and often the the nails stay put and pull through the batten. I tell the lads when fixing the first eaves batten, never to send the nails home until you are sure. You can end up wrecking the felt too, trying to remove the battens.

Sounds like softer battens/ laths rather than grippier nails

 

[noseall]

Sounds like softer battens/ laths rather than grippier nails

Possibly. But even levering the nail out afterwards - you shear the nail head off and end up smashing the spike into the rafter.

 

[aveatry]

Possibly. But even levering the nail out afterwards - you shear the nail head off and end up smashing the spike into the rafter.

Right - your the builder but would it be better ( not ideal) to just snap off the nail after the nail has pulled through the batten.
I had to dismantle some wooden pallets and they were ringshank nails inpossible to remove so I found the best way was to use a 10mm hole saw and saw/drill over the nail releasing the pallet plank and then whacking the remaining 10mm plug/nail with a hammer and snapping the nail.