Ancient Egyptian, Greek, and Roman architects made extensive use of Post-and-lintel construction to support the roofs of temples and public places. Two vertical posts on either side of a beam (or lintel) hold up the beam and everything above the opening. This is a strong support when the structure is level and gravity pulls down evenly on the structure. The weight of the wall above the lintel is the load.
In Post-and-lintel construction they would use many kinds of stone. Stone and marble were chosen for important monuments because they are incombustible and can be expected to endure. Stone is also a sculptural material; stone architecture was often integral with stone sculpture. The use of stone has declined, however, because a number of other materials are more amenable to industrial use and assembly. Some regions lack both timber and stone; their peoples used the earth itself, tamping certain mixtures into walls or forming them into bricks to be dried in the sun. Later they baked these substances in kilns, producing a rang
This increased their own dead weight, which significantly reduced the distance they could reliably span to about eight feet on average. Some stones weigh as much as forty tons. As Stonehenge is approached, the forty giant stones seem to touch the sky. Actually, this sort of construction had its limitations in that the size and weight of the stones being used limited the space contained by the structure. On Salisbury Plain in Southern England stands Stonehenge, the most famous of all megalithic sites. Today, less than half of the original stones still stand as their builders planned. Others are smaller, weighing only five tons. Many of the once upright stones lie on their sides. As a result the lintels had to be made especially thick and wide in order to increase the amount of mass they had to resist these tensile stresses. Construction took place in three phases, over 25 generations. While stone has high compressive strength, it is comparatively weak in tension. This grossly underutilizes most of the beam's other mass.