Landing - A platform between flights of stairs or at the termination of a flight of stairs.

Lath - A building material of wood, metal, gypsum, or insulating board that is fastened to the frame of a building to act as a plaster base.

Lattice - A framework of crossed wood or metal strips.

Ledger Strip - A strip of lumber nailed along the bottom of the side of a girder on which joists rest.

Light - Space in a window sash for a single pane of glass. Also, a pane of glass.

Lintel - A horizontal structural member that supports the load over an opening such as a door or window.

Lookout - A short wood bracket or cantilever to support an overhang portion of a roof or the like, usually concealed from view.

Louver - An opening with a series of horizontal slats so an ranged as to permit ventilation but to exclude rain, sun, light, or vision. See also Attic ventilators.

Lumber - Lumber is the product of the sawmill and planning mill not further manufactured other than by sawing, re-sawing, and passing lengthwise through a standard planning machine, crosscutting to length, and matching.

Lumber, boards - Yard lumber less than 2 inches thick and 2 or more inches wide.

Lumber, dimension - Yard lumber from 2 inches to, but not including, 5 inches thick and 2 or more inches wide. Includes joists, rafters, studs, plank, and small timbers.

Lumber, dressed size - The dimension of lumber after shrinking from green dimension and after machining to size or pattern.

Lumber, matched - Lumber that is dressed and shaped on one edge in a grooved pattern and on the other in a tongued pattern.

Lumber, shiplap - Lumber that is edge-dressed to make a close rabbeted or lapped joint.

Lumber, timbers - Yard lumber 5 or more inches in least dimension. Includes beams, stringers, posts, caps, sills, girders, and purlins