Sin autem aliqui paries perpetuos habuerit umores, paululum ab eo recedatur et struatur alter tenuis distans ab eo, quantum res patietur, et inter duos parietes canalis ducatur inferior, quam libramentum conclavis fuerit, habens nares ad locum patentem.
But if any wall shows continued damp, we must go a little behind it, and build another wall, thin and distant from the first, as far as the case admits. Between the two walls, a gutter must be laid lower than the level of the room, with outlets into the open.
final_alignments\Vitruvius_Architecture_Book_7.json