U-Value - the capability of a substance to transfer heat. Used to describe the conductance of a
material, or a composite of materials, in construction. Its reciprocal is referred to as an R-value.
Vapor Retarder - a material or construction that retards water vapor migration, generally not
exceeding one perm for ordinary houses in non-extreme climates.
Wall - a part of a building that divides spaces vertically.
Bearing wall - a wall supporting a vertical load in addition to its own weight.
Curtain wall - a nonbearing exterior wall, secured to and supported by the structural members
of the building.
Nonbearing wall - a wall that does not support a vertical load other than its own weight.
Water-Repellent - a material or treatment for surfaces to provide resistance to penetration by water.
Waterproofing - treatment of a surface or structure to prevent the passage of liquid water under
hydrostatic, dynamic, or static pressure.
Weephole - a small hole allowing drainage of fluid.
Windows and doors -
Frame - an assembly of structural members that surrounds and supports the sash, ventilators,
doors, panels, or glazing that is installed into an opening in a building envelope or wall.
Glazing - a material installed in a sash, ventilator, or panel such as glass, plastic, etc.
Head - an upper horizontal member of a window or door frame.
Jamb - a vertical member of a window or door frame.
Mullion - a member used between windows or doors as a means of connection, which may or
may not be structural.
Muntin - a member used between lites of glazing within a sash, ventilator, or panel.
Operable - describing a sash, ventilator, or panel designed to be opened and closed.
Sill - a lower horizontal member of a window or sliding door frame.
Working Drawing - A detail drawing, usually produced by a draftsperson under direction of an
architect, engineer, or other designer showing form, quantity, and relationship of construction
elements and materials; indicating their location, identification, grades, dimensions, and
Working Life - the time interval after opening a container of a single component sealant, or after
mixing the components of a multi-component sealant, during which application and tooling is