I have a lot of tongue and groove, reversible shiplap / v-groove boards from a big box store. I would like to use them for a plank ceiling that is 25x8ft. It is unclear to me how these boards allow for expansion since they sit flush together with seemingly no expansion gap on the V-groove side (see image). If I use the shiplap side down, do I need to rip the tongue to allow for expansion?
I plan to treat the boards before installation. I live in an area that stay low humidity year round.