Valley - The internal angle formed by the junction of two sloping sides of a roof.

Vapor Barrier - Material used to retard the movement of water vapor into walls and prevent condensation in them. Usually considered as having a perm value of less than 1.0. Applied separately over the warm side of exposed walls or as a part of batt or blanket insulation.

Varnish - A thickened preparation of drying oil or drying oil and resin suitable for spreading on surfaces to form continuous, transparent coatings, or for mixing with pigments to make enamels.

Vehicle - The liquid portion of a finishing material; it consists of the binder (nonvolatile) and volatile thinners.

Veneer - Thin sheets of wood made by rotary cutting or slicing of a log.

Vent - A pipe or duct which allows flow of air as an inlet or outlet.

Vermiculite - A mineral closely related to mica, with the faculty of expanding on heating to form lightweight material with insulation quality. Used as bulk insulation and also as aggregate in insulating and acoustical plaster and in insulating concrete floors.

Volatile Thinner - A liquid that evaporates readily and is used to thin or reduce the consistency of finishes without altering the relative volumes of pigment and nonvolatile vehicles.