sheathing, overlay, overlayer -- (protective covering consisting, for example, of a layer of boards applied to the studs and joists of a building to strengthen it and serve as a foundation for a weatherproof exterior)
Overview of verb sheathe
The verb sheathe has 3 senses
sheathe -- (cover with a protective sheathing; "sheathe her face")
sheathe -- (enclose with a sheath; "sheathe a sword")
sheathe -- (plunge or bury (a knife or sword) in flesh)