Week 23 – Snow in Rome, and the Choice of Stones for their Durability at Ercolano

Snow in Rome – view from the Gianicolo, with the 3-arched loggia of Villa Farnese at the mid right, and the twin cupolas of the Villa Medici at the top center.

 This doesn’t seem like much of a stretch – I’ve been at the Pantheon on nice, sunny fall days when it is so crowded with tourists that one can hardly get through the doors. If you’ve read Anthony Doerr’s enjoyable book, Four Seasons in Rome (a perennial favorite here at the American Academy) you’ve read him hoping and wishing repeatedly throughout the winter (unsuccessfully) that it will snow while he is here in Rome, so he can see snow descend into the Pantheon.  This was described to him as a “lifechanging experience”.

This winter, it seems as if anytime there’s been even a remote possibility of the temperature momentarily dipping below freezing, I’ve heard someone say excitedly, “There’s a chance it might snow tonight!”   I heard some similar hopes expressed Thursday evening at the Academy, but I more or less took them with a grain of salt. The weather forecast I saw only had an overnight low of 35 Fahrenheit. As a native Bostonian, I realize that it doesn’t just instantly snow if the temperature drops near freezing.

Friday morning, I was playing with my daughter in the living room of our apartment, when my wife looked out the window and said – “Oh my gosh, it’s snowing!” I stepped out onto our terrace and watched the flurry of flakes fly past the umbrella pines, as nearby Villa Aurelia, just across the street, seemed distant and gray in the flurry.

Villa Aurelia in the snow, as viewed from my terrace, Friday 12 February

I had a mid-morning appointment for my project in Rome’s Centro, so I quickly ate a bowl of cereal, grabbed what I needed for my appointment, threw on some clothes (no shower), and headed down the hill toward the Pantheon. As I hurried down the slippery hill (no salt, no sand, no shoveling, no traction), I wondered if taking the extra 5 minutes to eat that bowl of cereal was a mistake – had I delayed too long?   I quickly estimated that I’d arrive at the Pantheon about 8:50 AM – the doors open at 8:30.

As I rounded the corner and approached the Pantheon from behind, I could see some white temporary fencing and barricades at the front of the Pantheon that weren’t there only 2 days before.  Oh, no – the temporary fencing must be for crowd control, I thought – was I too late? I curled around the corner of the temporary fencing at the portico, and followed it along. 

Looking through the bronze doors of the Pantheon to the portico, with temporary white fencing at left.

To my surprise, there wasn’t any throng of people in the piazza – I looked quizzically at the massive bronze doors, swung wide open, with a guard standing at the door, but no crowd waiting to get in. It looked like it was essentially empty inside. I’d never seen it this way – was it closed? Was the guard the bearer of the bad news?  Were they closed and simply clearing the snowy slush and mopping the floor inside?

I walked through the massive bronze doors, inside, past the guard who nodded and smiled. It was open as usual after all. There were only 4 or 5 other people inside – far and away the fewest people I’d ever seen in the Pantheon. One was Scott, an American architecture professor whom I know, who teaches in a U.S. program abroad here in Rome. We admired the falling snow inside, took photos, and chatted for a while.

On a snowy morning, the American Academy crowd gathers in the otherwise almost empty Pantheon

After about half an hour, the crowd had grown to about 12-15 people, almost all of them Americans, and almost all academics, almost all of them looking tired and disheveled from hurrying there through the snow.

Between the two of us, Scott and I knew almost everyone there. It seems we’d all been deceived by the same urban myths (or perhaps American Academy in Rome myths) that everyone in Rome descends on the Pantheon when it snows.   This myth-busting could seriously call into question other American Academy legends, like the one about Louis Kahn nearly being thrown out for lying on his bed for hours on end, “studying the light” on the ceiling, or the one about the female ghost who periodically appears in the basement of the library very late at night.

Snow falling through the oculus of the Pantheon

Streetscape at Ercolano, showing building walls, curbstones, and street paving.

Last week I discussed the comparative durability of the various masonry materials used in the walls at the 1st century A.D. archaeological site Ercolano (Herculaneum). The local stones near Ercolano vary widely in their hardness and durability. The tug-of-war is this: the stones that tend to be softest and easiest to quarry and work (e.g., cut or split into useful shapes) tend to be the least durable, and the conversely those that tend to be hardest and most durable also tend to be the most difficult and time consuming to quarry and work. Rather than use the most durable (and most difficult and time consuming) or the least durable (and easiest and least time consuming) stone everywhere, the Romans made prudent choices in where they chose to use each of their local building stones at Ercolano.

Local tufa giallo stone in original walls at Ercolano. A fragment of the stucco rendering remains at the base of the wall.

At Ercolano, the Romans used their LEAST durable common local stone, tufa giallo (yellow tuff) for building walls, which are above grade, and consequently exposed to less moisture and impact than stones used for paving or curbs. Further, they covered their walls with limewashed stucco, both to limit exposure of the least durable stone to precipitation, and so the stucco could serve as a “sacrificial layer”, to take the majority of the weather and the deterioration. The limewashed stucco would gradually deteriorate and need to be periodically renewed, but it would save the underlying tufa giallo from more rapid weathering and deterioration. Most of that exterior stucco does not survive, but fragments of it remain here and there.

Remnants of stucco rendering on exterior walls at Ercolano at right (red) and upper left (gray)

Polygonal-shaped basalt street pavement at Ercolano. The stones are about 1 foot deep.

They used their MOST durable stone, a local black basalt, for paving the streets. This local basalt is extremely hard and durable, and ideal for the torturous abuse and exposure of street paving. In fact, a similar black basalt is still used today for street paving in Rome (in the form of the familiar 3 or 4 inch square pietrini paving stones so synonymous with Rome). Thus the most durable stone was used for the most severe exposure – paving on a horizontal surface that other surfaces (sidewalks, roof drains from abutting houses) drain onto, that was often wet, and that sees daily, heavy abrasion from foot traffic, cart wheels, etc.

Curb stones at Ercolano

Stones of INTERMEDIATE durability (e.g., tufa rosidis) tend to be used in exposures of intermediate severity – like curb stones or stair treads. The curb stones are installed vertically, rather than horizontally, and are raised above the level of the pavement, so they aren’t subject to as severe an exposure to water as the pavement, (but more severe than the building walls). Stair treads obviously receive a lot of foot traffic, but no impact from the wheels of carts. Similarly, the curbstones receive far more impact (e.g., from feet and the wheels of errant carts) than building walls, but less than the street paving.

Almost no one has an unlimited budget or unlimited time for construction. Even the ancient Romans, known for building exceptionally well, and exceptionally durably, did NOT use the very best materials everywhere. On the contrary, even 1900 years ago at Ercolano, good design for durability involved making smart choices about where less durable materials would be sufficient (and how to help those materials succeed, as they did with their sacrificial stucco rendering), where more durable materials were needed, and where only the best and most durable materials would suffice. Some things never change.

View of the excavated Roman town of Ercolano, buried by the eruption of Mt. Vesuvius in 79 A.D.

The American Academy in Rome in the snow - Friday 12 Feb. 2010

Rome in the snow - view south from my terrace, 12 Feb. 2010

Nicholas and Allegra Brennan with their snowman in the American Academy's Bass Garden

My daughter Caroline and I in the snowy Bass Garden, with flowers at our feet.