cladding

The sheath surrounding the glass or plastic core of a piece of fiber optic cable. It prevents signal loss, and physically protects the core of the cable.

After the government decided to remove precious metals such as silver from the American coins in the monetary system, they used coins with copper centers with a nickel metal sheath on the outside to keep them the same color and prolong the service life. The sheathing was called cladding.

Clad coins were dimes, quarters, half-dollars and dollars in the US.

Cladding is an important architectural term. It is used to designate an exterior, structurally unimportant sheath of material, usually decorative. It is especially common in steel-frame buildings where the load-bearing members form only a skeleton to which a skin must be applied.

An example is the Empire State Building, which is clad in a gray limestone skin. The stone, besides being attractive in itself, gives the building a sense of permanence and dignity because of its apparent durability and weight. But of course, if the quarter-mile-high ESB had in fact been constructed of limestone blocks it would have been unbuildably expensive and would surely have plunged through the crust of the earth by now.

Interestingly, many "brick" houses built since the 1920s (especially in the USA) are merely clad, not structurally supported by the bricks--a cost-saving device which, in view of the economies of scale in building in the USA makes "brick construction" a feasible option these days. The development of cheap brick cladding was important in the early-20th-century opening up of certain historical revival styles of domestic architecture, which makes it interesting. Architects who could afford to be less concerned about building costs continued to exploit brick construction. Frank Lloyd Wright's vastly expensive and over-budget Lowell Walters House (1945) in Quasqueton, Iowa is a good example, at an estimated $100,000-135,000!

Similarly, the new Getty Center in Los Angeles, California is a concrete core clad with rough travertine, giving it a natural, "rusticated" look, as though it were really built of great blocks of the stone (see the interesting URL below).

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URLs.

http://academic.reed.edu/getty/cafeteria/Caf-Res-21.jpg (Travertine cladding being applied at the Getty Center.)
http://www.greatbuildings.com/buildings/Empire_State_Building.html (Empire State Building.)
http://www.iowadnr.com/parks/state_park_list/cedar_rock.html (Lowell Walters House site.)

Note. Friends, please bear with me as I issue a few shorter writeups defining a variety of architectural terms I'll need to draw upon for some larger writeups I have in the pipeline. I'll write up a collected list somewhere on the model of Dawggy's useful collection of nodes on poorly-known female artists. (And in any event, it's always worth adding factual content to the gel.)