I've got a line on some 5/16" X 4' X 8' Sierra Hardipanels, pre-
primed, for $22 each.

I'm planning on building a small lean-to style shed to house some
bikes, etc. over the winter as I need the garage for a winter project.
8' W x 6' D x 6' H at the front.

Can I use the Hardipanels right over the stud walls or do I need to
use sheathing under it?

Can I use the Hardipanels as roofing material - with felt-paper
covered sheathing underneath? There will be snow and the roof will
have a very shallow pitch, maybe 1:12. I was thinking kind of a board
& batten roof, with copious amounts of caulk under the battens.

Do you think I'd get a winter or so worth's of use out of this?