Ancient Greek stone architecture with its bleached symmetry and powerful ornamentation often looks as though it’s survived for more than 2,000 years simply through force of presence. A closer look, however, at the stones that make up classic Greek architecture reveals curious channels and depressions inside the centers of the stones that were carved to make up columns.
As the Smithsonian Magazine notes:
When the current restoration [of the Parthenon] began in 1975, backed by $23 million from the Greek government, the project’s directors believed they could finish in ten years. But unforeseen problems arose as soon as workers started disassembling the temples. For example, the ancient Greek builders had secured the marble blocks together with iron clamps fitted in carefully carved grooves. They then poured molten lead over the joints to cushion them from seismic shocks and protect the clamps from corrosion. But when a Greek architect, Nikolas Balanos, launched an enthusiastic campaign of restorations in 1898, he installed crude iron clamps, indiscriminately fastening one block to another and neglecting to add the lead coating. Rain soon began to play havoc with the new clamps, swelling the iron and cracking the marble. Less than a century later, it wasclear that parts of the Parthenon were in imminent danger of collapse.
The use of lead to hold iron in stone persisted in Harlem through the early 20th Century. The former All Saints Church at 129th and Madison is surrounded by a substantial iron fence – mostly to protect pedestrians from falling into the moat-like window well that permits sunlight to enter the basement level of the building.
A close look at the fence (embedded in limestone kerbs) shows that the builders of All Saints understood the peril of embedding iron in stone. (The danger is mostly in the process of oxidization, or rusting, which swells larger than the original iron with pressures that can split the stone while simultaneously rotting the iron.)
In the image above and below you can see the grey/white lead (think of the paint color – now not made because of its toxicity – lead white, which was made from oxidized lead…) around the iron fence vertical – which is itself rusting, but not splitting the soft limestone in which it is placed.
Today, quality contemporary construction embeds a non-ferrous vertical rod (typically aluminum) in the ground/support and then joins the ferrous fence (steel, now, not iron) which remains susceptible to rusting over the decades, to the aluminum post.
The example, below, shows the Choir Academy school’s fence, steel attached to embedded aluminum.
Classic TV commercials from the 70’s
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