Lally Column - A post supporting a girder or I-beam.
Lath - Mesh metal, plasterboard, or thin wooden strips used as a foundation for plaster or stucco.
Lattice - A grille created by cris-crossing or decoratively interlacing strips of material.
Leaded Window - A window decorated by artistic inserts of lead.
Leader - Down spout
Ledger Strip - A wooden strip nailed along the bottom face of one support to aid in the support of another member brought.
Light - A window glass.
Lintel - A horizontal supporting crosspiece over an opening.
Live Load - The weight of people, things and materials that are not always present at the same place in a building.
Louver Vent - An opening fitted with a series of sloping slats arranged to admit light and air but shed rain.