Sheltering Archaeological Sites: A Guide to Ten Papers on Protective Roofs

A protective roof over an adobe ruin in the Southwest: the Great House at Casa Grande Ruins National Monument, Arizona. NPS.

A protective shelter — a roof or enclosure over an exposed ruin — can save an archaeological site, or harm it, or simply fail to help. The National Park Service collected the abstracts of a set of papers on the question. What they cover, in brief:

Deciding whether to shelter

• A values-based method (Neville Agnew). Decisions should rest on what makes the site valuable and on a close understanding of the threats and decay processes at work — and should build in performance evaluation from the start, something almost never done. Examples include the Laetoli (Tanzania) and Lark Quarry (Australia) trackway sites, an experimental shelter measured in detail, and published studies of a shelter over petroglyphs.
• Three shelters in Sicily (Nicholas P. Stanley-Price and Jukka Jokilehto). In the 1950s the architect Franco Minissi designed shelters at Gela, the Villa Romana del Casale (Piazza Armerina) and Heraclea Minoa. The paper places them in the Italian restoration thinking of the time — Cesare Brandi's theory and Minissi's idea of making sites part of contemporary life as museums in the open (musealizzazione).

Setting criteria and building

• Petra, Jordan (Gaetano Palumbo). A 1993 design competition for a shelter over a Byzantine church excavated in 1991–1992 produced a winner but no building. Instead architect Robert Shutler worked with Jordanian and international archaeologists and heritage managers on a reversible space-frame shelter. Lesson: stakeholders and specialists must cooperate from the decision through construction.
• Fort Selden, New Mexico (Troy D. Thompson and Michael R. Taylor). The state monument's exposed adobe ruins of a military post, established in 1865, might get a shelter. The paper sets out preliminary conservation, design and construction criteria — and how to square them with public expectations of an American historic site — so that a future shelter can be judged against them.
• Lot's Basilica, Jordan (Zaki Aslan). Design criteria should come from the site's heritage management, and design should respond to conservation needs. Climate-based design and computer simulation of a shelter's environment, despite their limits, help predict how well an enclosure will protect a site.

Judging how shelters perform

• Mesa Verde National Park (Kathleen Fiero). The park has sheltered excavated mesa-top sites since 1919 — over twenty shelters, from informal structures to architect-designed ones. Of the twelve standing: two informal ones by park staff over sites not open to the public; one metal shelter from 1969; and nine of precast concrete with wooden roofs from 1984–87. The designed shelters have protected their sites fairly well, and when a wildfire in 2000 damaged four shelters, the archaeology beneath was unharmed.
• Blackwater Draw, New Mexico (Pamela Jerome, Michael R. Taylor and John R. Montgomery). At the type site of the Clovis culture, dating back 12,000 years, a shelter was proposed in 1995 for Paleo-Indian finds excavated in 1983–4 and displayed in place. Experts made recommendations; the shelter was built several years later and re-evaluated in 2000.

Tools for practitioners

• An annotated bibliography (Martha Demas) of the literature through 2000, in six languages. Given how many shelters exist, the literature is thin — and it rarely reports how they performed.
• Italy's research project (Maria Concetta Laurenti). An Italian government-backed institute and the Istituto Centrale per il Restauro in Rome were developing a standard planning method for shelters over three years, to finish in 2002, including a database of site characteristics modeled on Italy's cultural heritage risk map, with two pilot shelters planned.

Sources

Based on "Protective Shelters for Archaeological Sites in the Southwest USA," National Park Service, which reproduces the papers' abstracts. The abstracts are the authors' own work and are summarized here, not quoted. The Fort Selden abstract gives the post's occupation as 1865 to "1981"; the post closed in the nineteenth century, so only its founding date is given here. Photograph: NPS.