Labor Burden 
Employer's charges for employee benefits, wages, taxes, insurance, etc.

Laches 
"Doctrine of laches," is the failure to timely assert one's rights or claim in any given matter. This failure to take action on a timely basis misleads an adverse party that no breach has occurred. 

Lacing 
Interweaving of roof shingles at intersections. 

Lack of Fusion 
Poorly done weld, which has areas of incomplete weld fusion, where the weld isn't fused to the base metal in all places, making the strength of the weld weaker. 

Lacquer 
1. Substance, consisting of such resinous materials as ether, shellac, gum, and alkyd resins dissolved in alcohol or other solvent, which will evaporate rapidly when, applied, leaving a tough, adherent film with a hard, smooth coating on such items as wood furniture. 
2. Resinous varnish. 

Ladder 
Framework which consists of two parallel side pieces which are connected by a series of rungs or crosspiece which are used for climbing up and down. 

Ladder Bar 
Reinforcement for a masonry joint, which is in the shape of a ladder, with its parallel and cross wires. 

Ladder Tray 
Cable support similar in shape to a ladder, with side rails connected by periodic crosspieces.

Lag Bolt or Screw 
Wood fastener, which has a square or hexagonal shaped head with a pointed, threaded shank, resembling a thick wood screw.

Lagging 
Insulation for thermal piping, which minimizes heat loss through a pipe wall. 

Lagging Indicators 
Six lagging indicators issued by the government consisting of unemployment rate, corporate expenditures, labor cost per unit, loans outstanding, bank interest rates and book value of trade inventories, trail behind aggregate economic activity. 

Laitance
White dusty surface film which occurs when there is too much water, left to evaporate, in the concrete mix, or when it has not been worked properly during finishing. 

Lally Column 
Circular, concrete filled pipe, which is used as a support for beams and girders.

Lamella 
1. A thin plate-like part, layer or structure. 
2. Wood that is laid out and joined in crosspieces to create a diamond pattern in this roof framing method. 

Laminate 
Plastic-like material used as countertops, which is known by several brand names, including Formica. 

Laminated 
Composed of or built in thin sheets or layers, that have been bonded, glued or pressed together, often under heat. 

Laminated Glass 
Layers of plate glass that have plastic sheeting between the layers, which adheres to the glass so that, if broken, it will remain in one piece. 

Laminated Veneer Lumber (LVL) 
Created by parallel lamination of veneers into a thickness normal to solid sawn lumber, which is ¾" to 2 ¼" and is considered engineered lumber. 

Lampblack 
Black coloring agent, of nearly pure carbon pigment made from soot. 

Lamp Cord 
Also known as zip cord or SP wire, these small diameter stranded wires are covered with rubber insulation. 

Lampholder 
Lighting fixture that is a simple holder for a light bulb.