by Risa Wolf

Created on: December 18, 2010   Last Updated: December 20, 2010

All construction above ground level is a battle between the forces of gravity that pull down and the strength of materials that are used to build up. Humans like to be able to stand up when inside a shelter; hence, walls are usually built straight up to head height. For even the simplest shelter, however, once the walls are up, the problem then becomes how to roof the building under construction. The corbel (or cantilever) is one ancient solution to the problem.

♦ What is corbel construction?

Technically speaking, a corbel is a bracket member; that is, one end is built into or fixed by some means to a wall and the other end projects into the air. The projecting end carries weight. This weight could be, for example, a balcony or a roof. When each corbel is abutted to the next one in “rounds,” the result is a slowly decreasing opening as each round completes its circuit until the entire area is enclosed.

Corbel construction in stone requires massive walls and an incredible amount of material. to provide stability against the pull of gravity. With modern steel and concrete, cantilevered or corbelled construction, has endless uses and does not require massive amounts of material. Corbelling has a venerable history and the technique has come a long way since its paleolithic origins and early corbel structures.

♦ The beehive huts of Ireland

Although no precise dates can be stated, the prehistoric beehive huts of Ireland give an indication as to the origin of the concept. Beehive huts imitate a cavern inside and a heavy rockfall on the outside.

These early huts are constructed by the dry-wall technique. This means that the stones are not cut or quarried to shape, but piled and fit to each other as much as possible. Only the weight and mass of the stone holds the structure together. Still, as time passed, there were innovations and improvements.

The ability to defend was as important as keeping off the elements and the older the beehive hut, the smaller the entry (after all, if someone has to crawl through to gain entry, it would require only a bop on the head to stop an intruder). As the centuries passed, larger entries with wooden doors and wooden lintels and posts appear. In the West, the next improvement in the techniques of corbel construction appears in the Eastern Mediterranean.

♦ The Tholos tombs of the Mediterranean

A tholos tomb is still a beehive, but with a striking difference. The construction technique is still

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