How to fasten boards in reverse board and batten siding over rigid mineral wool
We’re building in climate zone 4C. The design calls for 2×6’s @ 24″ O.C. with dense-packed cellulose, plywood sheathing, WRB, 3″ rigid mineral wool and board and batten cedar siding over a rainscreen. The contractor brought up the concern of using horizontal firring strips behind the board and batten siding for the rainscreen. After doing some research on GBA, it sounds like the horizontal firring strips are fine and will allow for enough drying behind the siding. But I also saw the suggestion of doing a reverse board and batten, using the battens as the rainscreen. I like this idea since it would require less wood, fewer fasteners and less labor. We could attach the cedar battens (1×3 or 1×4’s) through the mineral wool into the studs. But how would we attach the boards? Could we nail them to the battens or would we need fasteners to go through the rigid into the sheathing?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Board-and-batten siding usually requires 1x8s, 1x10s, or (rarely) 1x12s for boards.
You wrote, "We could attach the cedar battens (1x3 or 1x4's) through the mineral wool into the studs." I don't see how you could do that, since the battens need to be about 8 or 10 inches on center, and the studs are 16 or 24 inches on center.
In theory, you might be able to attach the battens to the plywood sheathing. But that is less satisfying (and less secure) than fastening the battens to horizontal furring strips.
Here is a link to a previous Q&A thread that discussed fastener patterns for reverse board-and-batten siding: