Lacquer: a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high gloss and that can be further polished as required. More durable than shellac.
Lally Column: cylindrical steel member for supporting beams and girders. Can be filled with concrete sometimes.
Lap Joint: a technique for joining two pieces of material by overlapping them. A lap may be a full lap or half lap. The full lap is a very basic method of joining two members and requires little or no joinery skills to make. It requires some form of mechanical fastener, such as a nail or screw, to be effective. It offers no resistance to racking but some resistance to twisting and shearing depending upon the fastener used.
Lath: building material fastened to the framing to provide a base for application of plaster. Can be made of wood, gypsum, metal or insulating board. The lath and plaster method declined in the 1950s, as it was replaced by the more efficient drywall, although many existing buildings are built using the technique.
Ledger: a support strip attached to vertical structural members or framing for supporting joists or other horizontal member.
Let-in: generic term for any notch in a block, joist, stud or other member holding one or more other members.
Level Transit: surveying device used for checking the plumb in new construction walls.
Light Frame Construction: method of construction based around structural members, usually called studs, which provide a stable frame to which interior and exterior wall coverings are attached, and covered by a roof comprising horizontal ceiling joists and sloping rafters (together forming a truss structure) or manufactured pre-fabricated roof trusses—all of which are covered by various sheathing materials to give weather resistance. Generally restricted to residential buildings. Also called Light framing or Light construction.
Lineal Foot: measurement having length only, pertains to a line one foot long, as opposed to a square or cubic foot.
Lintel: horizontal structural member supporting the entire load over an opening in a wall such as a door or window.
Load Bearing: a structural member in a building supporting the weight of a structure.
Lock Block: a block shaped piece of wood joined to the inside edge of a hollow core door‘s stile, which a lock is fitted to. On flush doors, there is a lock block on each stile.
Lookout: a structural member that runs between the lower end of a rafter and the outside wall, used to carry the underside of the overhang.
Lumber: refers to solid wood product from saw and planing mills with no other processing than sawing, resawing, planing lengthwise and crosscutting to length. Lumber is supplied either rough or finished. Rough lumber is the raw material for furniture-making and other items requiring additional cutting and shaping. It is available in many species, usually hardwoods. Finished lumber is supplied in standard sizes, mostly for the construction industry, primarily softwood from coniferous species including pine, fir and spruce (collectively known as Spruce-pine-fir), cedar, hemlock, but also some hardwood, for high-grade flooring.