We are pre-staining cedar tongue and grove siding for the interior of a cathedral ceiling on an addition. Here's the question: Should I stain the backside of the siding also? The lumber yard recommended it. The interior ceiling joists are twelve inches deep filled with ten inches of insulation and a two inch air gap running up to the ridge vent. Vapor barrier plastic seals the whole thing. With 200 pieces of siding I don't want to give myself unnecessary work.
Any thoughts?