"Firewood storage"

[Jacob10]

I'm building a wood shed and wondering what dimension I should use for the "battens" under the metal roof? I plan to place the "battens" directly on the rafters. The metal screws are 35 mm long.

Roffe, a happy amateur

 

[fribygg]

If possible, coarse enough so that the screw does not go through, 45*70 becomes strong and good if it feels reasonable economically.
(I myself have a low-budget wood shed made of sapwood and sawmill waste, maybe 100 years old sinus-corrugated thick metal roof without battens underneath)