Arc Boutant Historic Preservation ProgramSummer 2002

Arc Boutant Historic Preservation Program:Summer Field Course 2002

Chiesa della Madonna delle Virtù:

Documentation and Analysis

Figure 2. Iron cross/weathervane surmounting campanile of the Chiesa della Madonna delle Virtù.
Figure 1 (cover). Close-up of the campanile of the Chiesa della Madonna delle Virtù with view of Sasso Barisano in background.

925 Jackson Street, Benicia, California 94510, USA

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Arc Boutant Historic Preservation ProgramSummer 2002


Preface and Acknowledgments 3

Program and Site Overview 4

Year 2002 Focus 7

Lectures and Fieldtrips 8

Disegnatrice Giulia Gioia and Signora Anna Mastrogiulio 8

Disegnatore Enzo Viti 10

Dott. Architetto Pietro Laureano 11

Scultori Tina Latorre and Roberto di Trani 12

Dott. CesarePassarelli 13

Dott. Architetto Biagio La Fratta 16

Dott.essa Rita Padula 18

Dott.essa Architetto Antonella Guida 19

Dott.essa Dorothy Zinn 20

La Chiesa della Madonna delle Virtù (II) 21

Description and Historical Background 21

Analysis and Treatment of Physical Conditions 25

Drawings and Graphic Analysis 28

Plan of Action: Priorities for Intervention 39

Social Acculturation 40

Participant Profiles 41

This publication was written, designed, and produced by Anne Toxey with contribuitons by Chad McPhail and technical assistance by Patrick McMillan. All photographs reproduced by permission of Anne Toxey or Chad McPhail.

Copyright © 2003 by Arc Boutant Historic Preservation Program

All rights reserved. Printed in the United States of America.

Arc Boutant Historic Preservation ProgramSummer 2002

Preface and Acknowledgments

Described in this publication is the fieldwork carried out during Arc Boutant Historic Preservation Program's 2002 summer course. This took place in the ancient Sassi cave sectors of the Southern Italian city of Matera, capital of the province of Matera in the region of Basilicata. The course was a two-week session culminating in the extensive analysis of the Sassi church, the Chiesa della Madonna delle Virtù (II).

Carved into the wall of a Basilicatan ("Lucanian" by local preference) ravine in visible layers reflecting architectural methods and aesthetics from thousands of years of human habitation, the site of Matera is a wonderful teaching tool. It offers clear lessons in geology, physical and human geography, architectural history, and methods and theories of architectural restoration.

Course work focused on developing an understanding of the physical, anthropological, and historical makeup of the culture as background to investigation of preservation intervention. The work was done in collaboration with local authorities and invited experts on issues impacting the building. Course work was composed of: lectures, hands-on lessons, and site visits with Matera's rich faculty of well-known scholars and building professionals. The purpose of this publication is to document the research, analyses, and intervention proposals we made, to acknowledge the superlative cooperation of Materan scholars and building professionals, and to provide a basis for our continuing work in this most promising site.

I would like to express my gratitude and esteem for all institutions and individuals who contributed to the program with their participation and support. I thank the following scholars and professionals who lectured and led fieldtrips: Dott. Architetto Biagio La Fratta with the Soprintendenza per i Beni Ambientali ed Architettonici who invited our participation on the Virtù chapel, Dott.essa Architetto Antonella Guida and Dott.essa Anthropologo Dorothy Zinn from the Università di Basilicata, Dott. Cesare Passarelli, Scultori Tina Latorre and Roberto Di Trani, Dott. Architetto Pietro Laureano, Disegnatore Enzo Viti, Dott.essa Rita Padula, Signora Anna Mastrogiulio and Disegnatrice Giulia Gioia of the Museo Archaeologico Nazionale di Metaponto, and Signor Nunzio Paolicelli. I am grateful for their superb intellectual contributions to our program, which in turn support the safeguarding of this world monument and supreme example of Italian patrimony.

Anne P. Toxey

Program Director

Arc Boutant Historic Preservation ProgramSummer 2002

Program and Site Overview
Introduction to the Program

Arc Boutant (French term for flying buttress) is an academic program for the preservation of historic landmarks. Participants from around the world are invited to immerse themselves in a new culture while pursuing the hands-on conservation of endangered monuments. As the name states, the mission of the program is to fortify and maintain historic structures and to teach budding preservationists methods in materials conservation and historic building systems within the structures' cultural contexts.

The program's governing ideology is that appropriate intervention depends upon both a technical knowledge of materials, methods, and systems and an understanding of a site's history, culture, geography, and geology. Also discussed are the ethics, philosophy, and politics of preservation.

As with the program's previous projects in Paris at Château de la Petite Malmaison and in Normandy at Château de Montflaux, in the current project, the Sassi of Matera (a cave city in the region of Basilicata, Southern Italy), participants are lodged in the monument itself. Studying the structure from the inside out, students acquire an intimate knowledge of its history, construction, and conservation needs. Course work is designed as lectures, hands-on lessons, site visits, and practical research, all led by Matera's rich faculty of well-known scholars and building professionals demonstrating traditional and contemporary techniques of conservation. The Arc Boutant Historic Preservation Program is very pleased to be invited by the Italian national government (the Soprintendenza per i Beni Ambientali ed Architettonici) to participate in this exciting process of conservation and revitalization of world heritage. The opportunity to study the incomparable Sassi of Materaas well as the physical and cultural landscapes that produced themunder the instruction of the region's foremost scholars and restoration practitioners is a lifetime opportunity for the students.

The program is composed of three parts. The first part is an introduction to the culture and history of Matera and its region. Lectures and fieldtrips are led by local historians, architectural historians, anthropologists, and geologists. The second part of the course provides instruction in technical considerations of preservation of Matera's Sassi. Through lectures and on-site discussions, local preservation practitioners (architects, engineers, and artisans) train students in the conservation of structural as well as decorative material culture. The third part is a practical project conducted in collaboration with the national government's preservation office, the Soprintendenza Per i Beni Ambientali ed Architettonici. Participants applied the training they had received earlier in the course to a practical project.

The project selected was the physical analysis and restoration proposal for the Baroque chapel: La Chiesa della Madonna delle Virtù (II). Through historical research on the building, analysis of its physical condition, documentation with measured drawings, and consultation with Architetto Biagio La Fratta of the Soprintendenza and Ingegnere Cesare Passarelli, we developed a comprehensive plan for the building's safeguarding through conservation and restoration.

Arc Boutant Historic Preservation ProgramSummer 2002

Introduction to the Site: the Sassi of Matera

The significance of the Sassi was recognized by the international community in December 1993 when UNESCO placed the site on the World Heritage List. This classification honors the Sassi as a place of continuous human habitation for at least 350,000 years, dating back to the Paleolithic era. Also noted is the harmonious relationship achieved between human culture and the natural environment over a series of stages in human history.

The term Sassi means stones and refers to the rock hewn structures that compose the site. These were dug into the calcareous walls of a deep gorge cut in a high plateau. The earliest caves used were naturally formed, but as the population of the settlement increased, natural caves were enlarged and new caves dug in the soft stone walls of the ravine. Extracted material was reused to build exterior walls and entire rooms in front of the caves. By the middle ages, caves were used both as habitations and as chapels and monasteries. Byzantine and Latin frescoes decorate walls, and ecclesiastical architectural symbols are sculpted in situ in the several hundred rupestral churches that remain.

Figure 3. View of the Sassi dominated by the cathedral. The Chiesa della Madonna delle Virtù is located in the lower left corner of the image.

Arc Boutant Historic Preservation ProgramSummer 2002

The caves and their superstructures vertically descend the walls of the ravine. This hanging city had an intricate water collection system using channels and cisterns, some of which remains. A central spur of the Murgia separates the two Sassi zones: Sasso Caveoso to the south and Sasso Barisano to the north, facing Bari. On this stone outcropping in the 13th century, elite Materans constructed the fortified Civita which consisted of a city wall with round towers, a Romanesque cathedral, and palatial homes called palazzi. An increasing peasant population and the desiccation of surrounding lands due to the clear-cutting of indigenous oak forests led to poverty within the Sassi by the 19th century. Due to international broadcasting in 1947 of these squalid conditions through publication of Carlo Levi's Christ Stopped at Eboli, Matera became the "Shame of Italy." In the 1950s­70s, the Italian government relocated the entire Sassi population, abandoning the old town to deterioration. A law passed in 1986 reversed the earlier forced abandonment and allowed for the rehabilitation of the Sassi. The Arc Boutant Historic Preservation Program is very pleased to be invited to participate in this exciting process of conservation and revitalization of world heritage.

Figure 4. South facade of the Madonna delle Virtù.
Figure 5. Upper right corner of the south facade of the Madonna delle Virtù.
Figure 6. Altar of the Madonna delle Virtù.

Arc Boutant Historic Preservation ProgramSummer 2002

Year 2002 Focus

Carried out over a two-week course, the program this year followed the format of background research, technical training, and practical application. As in past years, discussions and fieldtrips, conducted by the director, Anne Toxey, and by local scholars, for example, Architetto Biagio La Fratta, Architetto Antonella Guida, Architetto Pietro Laureano, Anthropologo Dorothy Zinn, and Ingegnere Cesare Passarelli, composed the first two portions of the course. In addition, fresco restorer, Dott.essa Rita Padula and her colleagues demonstrated their work in the Palazzo Pomarici in the Civita, and Enzo Viti showed us his extensive church excavation and preservation work as well as the Acito and Partners large, touristic, reuse project for the Cava (quarry) della Palomba. Building an understanding of materials was a stone-sculpting workshop led by both Tina Latorre and Roberto di Trani. Regional fieldtrips brought us to Pisticci and to the Metaponto archaeological museum and parkas well as to the beach. The practical project was the study, analysis, documentation, and preservation plan for the Baroque chapel, La Chiesa della Madonna delle Virtù, located in Sasso Barisano. The magnitude of this project was significant, especially given the concentrated time period and the reduced size of our group (whose number was adversely impacted by post-September 11th travel jitters).

Being a small group, however, had other advantages. We were richly hosted by members of the community, who invited us into their homes to experience their expertise in regional cuisine (cucina Lucana). Our program this year was impacted in an interesting way by the effects of the Sassi preservation program, which we assist. Due to the success of this movement to generate cultural tourism, the Sassi are experiencing an increase in restored Sassi homes for visitor lodging. Our group benefited from this phenomenon by staying at the commodious Casa di Lucio in Sasso Caveoso.

Figure 7. Restoration of frescoes in Palazzo Pomarici (see also figs. 21­23).
Figure 8. Cava della Palomba, future site of commercial and recreational complex by Acito and Partners.

Arc Boutant Historic Preservation ProgramSummer 2002

Lecture and Fieldtrips
Ancient history and civilizations of Basilicata

Lecture and fieldtrip given by Designatrice Giulia Gioia and Signora Anna Mastrogiulio: July 7, 2002

Documented by Chad McPhail

Fifty miles south of Matera on the Ionion coast is located Metaponto, famous today for endless sand beaches and for Greek colonial heritage. Known in classical times as Metapontium, this city was a major colonial outpost for the Achaean Greeks whose temples still be seen and whose houses, streets, farmhouses, fora, and tombs are found through excavation.

In a tour of the Museo Archeologico Nazionale di Metaponto, Designatrice Giulia Gioia explained the social and political history of Basilicata up to and including the Greek colonization of the Italian peninsula. The region has been inhabited continually by human beings for three-quarters of a million years, and Matera itself was first inhabited during the Upper Paleolithic era. The earliest rock drawings documented date from the Mesolithic; weaving and pottery are introduced in the Neolithic. Around this time, bronze-working is mastered by the Anatoic civilization and exists alongside the Neolithic pottery culture. Among the museum's permanent collection are pieces of early Bronze Age pottery and jewelry. During the Bronze Age, an indigenous people known as the Enotri formed townships based around farming. There was some contact with Minoan and Micenean traders. Grapes were a common crop, and wine was manufactured.

Figure 9. Tavola Palatino, a temple to Hera outside the Agora of Metaponto

Arc Boutant Historic Preservation ProgramSummer 2002

With the arrival of the Greeks in the 7th century BC, wine became even more important. Bronze Age Greek culture permeated many aspects of indigenous Enottri life. The fusion of cultures can be seen in burial pracatice and in jewelry and pottery styles and practices. For example, one such pottery is called Apulian red-figure. It is characterized by the use of white and red figures in frenetic, horror vacui arrangements on a black ground. More advanced pottery techniques make their way from coastal trading posts, known as pokis, to inland areas, and with these new ideas come a new religion. The Greek wine cult of Dionysus gains popularity among the aristocracy, and wine becomes an important product. By the sixth century BC, the wine game of kottabos has filtered down to the lower classes as well.

Also working for the museum, Anna Mastrogiulio took us on an extensive tour of its associated archaeological park, the religious and civic center of Metapontium. This includes temples to Apollo and Hera ranging in date from 6th­5th centuries BC, altars, streets, fora, and perhaps of greatest significance, the Ekklesiasterion / theater. The older form (the Ekklesiasterion) was an immense local meeting hall. It is the only one known to have existed in Magna Grecia. It was later transformed into a Greek theater. Separated from this city center by several miles is the Tavola Palatino, which we also visited. This temple to Hera is in particularly good shape and commands a view of the countryside.

Until the fifth century BC, Metapontium served as a Corinthian-Greek center for the region. After Athens destroyed Corinth's colonial city of Sirus, Athenean (or Achaen) Greek culture dominated, and Metapontium was abandoned for the new city of Heraclea, nearby. At the same time, the Hellenistic-Enottrian culture was being threatened by the arrival of the indigenous Lucanian and Sabellic peoples from the north. Despite the threat, by the forth century BC, the Hellenistic-Enottrian wine cult enjoyed great popularity. When the Romans arrived in the third century BC, the Lucanians allied with them to oust the Greeks and subdue the Enottrians. Later, the Romans conquered the Lucanians as well.

Although there are no Greek structures found in Matera, there was habitation there throughout the Greek period. People in Matera surely traded with the surrounding Greek cities. Greek presence has been found in nearby Montescaglioso with the elaborate tomb of a Greek warrior. The Greeks remained a long time in southern Italy, and their influence was extensive. Nevertheless, despite 500 years of Greek and Hellenistic domination, local residents do not identify themselves with the ancient Greeks, whom they consider as outside dominators. Calling themselves Lucanians, they describe their ethnicity as Enottrian, untouched by the Greek, Roman, Islamic, Francobard, Spanish, and numerous other invading groups.

Figure 10. Anna Mastrogiulio in the Agora of Metaponto, Ekklesiasterion / theater visible in the background.

Arc Boutant Historic Preservation ProgramSummer 2002

Introduction to the region: the past and future of Matera

Fieldtrip conducted by Disegnatore Enzo Viti; July 8, 2002

Living up to his many professions (artist, designer, model-maker, draftsman, excavator, spelunker, and historian), Enzo Viti gave us a multi-dimensional tour of Matera, past and future. He took us to see some of the remaining prehistoric caves across the ravine from Matera and showed us Byzantine rock churches, ancient stone quarries, and ancient cistern systems. In addition, he took us to the 19th­20th-century quarry (now closed), the Cava della Palomba. Here, the local architecture firm of Acito and Partners, in collaboration with American landscape architect Lawrence Halprin, will be developing a large commercial, cultural, and tourism complex. As the model-builder of this project, Viti knew it intimately.

Next he took us to his studio to see the original drawings he made and photos he took of the excavations of several important Materan rock churches, including Santa Barbara, the crypts under San Pietro Barisano, the crypts under San Francesco di Assisi, and the crypt of San Eustachio located under the cathedral. He also showed us a sample of his extensive photograph collection of early 20th-century Matera as well as his considerable library of local history. Equally fascinating were his non-official oral histories of Matera, for example, atrocities carried out by the Conte Tramontano, the 14th-century local ruler who was assassinated by the people and the location of the Via Appia under the city.

Figure 11. Enzo Viti and Anne Toxey in the Cava della Palomba.

Arc Boutant Historic Preservation ProgramSummer 2002

Bioclimatic water systems of the rupestral culture

Lecture by Architetto Pietro Laureano July 9, 2002

Documented by Chad McPhail

Architetto and professore Pietro Laureano has spent much time researching ancient water systems in the Sassi and throughout the world. He has detected many similarities between Saharan water collection and those long-discarded systems he has found in the Sassi cave structures. In fact this research was the basis of his proposal to UNESCO proclaiming the significance and uniqueness of the Sassi. He theorizes that collection of water through a network of channels and drainage pipes into cisterns was a central motor determining location, organization, and growth of the Sassi. He also advocates the restoration and reuse of the water the system.

This water system as well asseveral other design features in the Sassi have been bypassed and even eliminated in many current restoration efforts for reasons of limited time and money, personal aesthetics, and lack of appreciation for their historical and cultural significance. Curved rooflines are rebuilt with strait pitches. Oddly shaped windows are replaced with standardized, squared versions. Modern systems of water distribution, seen (inaccurately) as more efficient and hygienic than the ancient systems, are more likely to be accepted by the population of Matera even for such uses as watering plants. Many of the residents of the newer part of the city lived in the Sassi or have parents who lived in the Sassi. To many, the idea of using a water system remembered as dilapidated and defunct goes against everything they were told when they were removed from the Sassi by the government. Modernism's philosophy of "newer is better" has been accepted by many former Sassi residents, and as a result, propositions to restore the cisterns and reuse them have been met with disapproval.

This attitude perpetuates the modernist policy imposed by the Italian government after World War II. After the war, the government, embarrassed by living conditions in southern Italy, provided legislation and funding for modernizing the Sassi. Instead of bringing running water, electricity, and sewerage to the traditional homes, however, the entire Sassi population was

Figure 12. Anne Toxey, Pietro Laureano, and Chad McPhail on the terrace of the architect's office overlooking Sasso Barisano.

Arc Boutant Historic Preservation ProgramSummer 2002

uprooted and moved to newly constructed apartments in new neighborhoods. Moving the people out of the Sassi proved to be an effective means of social control of the politically suspicious peasants. Lured off their fields by jobs in the construction industry (building their new accommodations), the peasants were transformed into wage-earners, dependent upon the government and large industry for jobs.

Tufo-sculplting methods

Demonstration conducted by Scultori Tina Latorre and Roberto di Trani, July 9, 2002

Documented by Chad McPhail

Tina Latorre and Roberto Di Trani are local artists who work in and around Matera. One of the materials they like working with is the local tufo stone. It is softer than stone from nearby areas, such as Apulia. Its presence at Matera allowed for the Sassi to be easily expanded and carved when first inhabited. Material extracted from cave digging was reused to construct rooms in front of the caves, thereby expanding them outward and giving the Sassi their distinctive look. The maleability of the stone makes it ideal for digging caves, quarrying, and sculpting; however, it also contributes to fast erosion. Exposure to air, however, will allow for the formation of a protective natural patina. If the conditions provide for this layer to form, the tufo will be relatively durable and resistant. In situations where water, wind, or human contact is especially present, however, the stone will deteriorate quickly. The inhabitants of the sassi fought this deterioration by coating the stone with a lime paint (calce). As the contemporary aesthetic prefers the aspect of natural stone to that of stone painted white, many preserved Sassi interiors are painted with clear chemical sealants. In the eyes of Latorre and Di Trani, however, the use of calce is more authentic, cheaper, more effective, and less environmentally damaging than that of chemical sealants.

Figure 13. Tina Latorre molding clay.
Figure 14. Chad McPhail testing the maleability of different stones.
Figure 15. Roberto Di Trani sculpting tufo.

Arc Boutant Historic Preservation ProgramSummer 2002

Di Trani carves architectural details from newly quarried stone to replace deteriorated pieces and often to add to restored structures. New elements include sculpted doorbell and vent covers, wall sconces, balustrades, cornices, and mural sculptures. Latorre's work is mostly free-standing sculptures or tables. Since the detail of much of their work requires a more tightly grained stone than the local tufo, they often used stone quarried from nearby towns. This is similar in color and composition but is harder and less crumbly. Di Trani and Latorre showed us the uses and sculpting properties of various local and regional limestones. They also demonstrated sculpting techniques.

Microclimate control and structural considerations

Lecture by Dott. Cesare Passarelli, July 10, 2002

Documented by Chad McPhail

Dott. Cesare Passarelli approaches Sassi preservation through sustainable design. He incorporates solar heating, photo-voltaic cells, passive shading, daylighting tubes, and heat pumps into his elegant solutions. This year he spoke to the group about the detection of microclimates and water problems in the Sassi. He also discussed solutions for stabilizing water problems in order to prevent further stone deterioration. Finally, he presented theories about energy-efficient temperature control and natural lighting for restored caves and built structures.

Being a contributor to erosion and to uncomfortable living conditions (both as humidity and as the facilitator of the growth of fungi, algae, lichen, and surface minerals), water is considered by many Sassi and ex-Sassi residents to be an enemy. [This is probably a large reason that they are disinterested in resurrecting the cistern water collection system.] Water enters the Sassi in three ways: external infiltration (from above), capillary action (rising damp from below), and condensation. External infiltration is addressed by patching fissures in ceilings and walls as well as in exposed surfaces above the structure. Plants growing above the structure should also be removed if possible to avoid introduction of moisture through roots (which cause further problems by expanding within fissures and causing spalling).

Exacerbated by the absorbent nature of tufo, capillary action is harder to control than infiltration. Its solutions are more complicated and invasive, depending upon a reduction of contact between the stone and moisture from below. Trenching alongside the building to encourage ventilation at the foundation is one method. Drilling holes in the foundation walls (to an acceptable point that does not compromise the integrity of the structure) will allow for drainage of moisture. In extreme cases (in Venice, for example) a waterproof resin can be injected into the foundation walls to strengthen them. A vapor barrier can also be introduced between courses of stone to act as a barrier between the water and the upper part of the building.

Condensation, the third way by which water enters cave structures, results from microclimates. The microclimates within caves are distinct from the weather outside. The temperature of caves is more constant than the outside air temperature. To determine the nature of the microclimates, devices are used to measure humidity and radiant heat as well as air tempera

Arc Boutant Historic Preservation ProgramSummer 2002

ture. In the summer months, when the inside­outside air temperature differential of the Sassi caves is greatest, damaging condensation occurs on the inner walls' surfaces as warmer air from outsides moves into the cooler damp cave. Since warm air cannot carry as much moisture as cool air, the rise in temperature causes the air to release its water content to cooler surfaces. This surface moisture damages wall frescoes common to the chiese rupestri (rock churches) and contributes to uncomfortable living conditions. The perceived solution of airing out a damp space can, in certain times of the year, do more harm than good by letting in warm air. The only viable solution to the problem is to bring the indoor temperature (within comfortable limits) closer to the outdoor temperature. As frescos require 55-65% humidity for optimum preservation, the indoor temperature must be 23° centigrade to keep humidity within these boundaries. A relatively non-invasive and natural way to achieve this environmental control was put into practice by Passarelli at the Chiesa della Madonna della Palomba in 1993. Here, a subfloor was constructed below the original floor and equipped with a solar-heated, radiating serpentine, which evenly heats the space in summer. The system does not need to run in the winter when the inside­outside temperature differential decreases. The water, heated by a direct solar exposure system hidden on the roof of an adjoining building, runs along the walls first to maintain as accurate a temperature control as possible nearest to the frescoes. The void between the floors provides for vents at either end of the church, which protect the floor from rising damp and ventilate the church. Ironically, the solution proved its effectiveness when winter temperatures froze the water in the solar heating system on the roof, due to negligence in maintaining antifreeze in the water. The photo-voltaic system that Arc Boutant students helped to design in summer 2001 is still being installed; its effectiveness cannot yet be determined.

In addition to the heating system, plantings were removed from the immediate area above the cave church, and fissures were filled with malta (a

Figure 16. Fresco inside the Madonna della Palomba.

Arc Boutant Historic Preservation ProgramSummer 2002

paste made from tufo powder and therefore chemically similar to the natural stone) to prevent external infiltration.

Other sustainable building practices (for example, for climatic control and lighting) will be put into practice in a residential application in an experimental building in the Sassi Barisano. This new construction will infill an area of the Sassi where considerable degradation has occurred and few records attest to what was previously built there, other than the caves that still exist. Discussed so far have been cave microclimates and conditions. Constructed buildings in the Sassi, however, act similarly to other constructions and are more responsive to changes in outside temerature. Likewise, the projected new construction will be dependent upon the outside temperature, while the ancient cave beneath experiences nearly constant year-round temperatures. In Passarelli's proposal, the two spaces will be climatically linked with a variation of an air to water system of heating and cooling. In the winter, the system will take the relatively warmer air from the cave and feed it through a compressor into the built structure. This will help equalize temperatures. Enhanced with heat calories extracted from outside air (however cold it may be, it still contains usable energy) the system should create comfortable living spaces. In summer, the system will take the cool air of the cave and use it to keep the built structure comfortable. To get light (a valuable commodity in the Sassi) into the cave, a solar tube will be used. Even at 12m in length, the tube will reflect 93% of the outside level of light into the space. To prevent the growth of sunlight-dependant algae, the light tube will be covered until the temperature control system is operational. These efforts of humidity control, water damage prevention, and light collection will help preserve the Sassi, while making them comfortable for habitation by modern standards.

Dott. Passarelli also visited our site (the Madonna delle Virtù) with us and assisted with our structural analysis and design of solutions.

Stone preservation techniques in the Sassi

Lecture and fieldtrip by Dott. Architetto Biagio La Fratta, July 11, 2002

Documented by Chad McPhail

Architetto Biagio La Fratta is an architect with the national preservation office, the Soprintendenza per i Beni Ambientali ed Architettonici. This office's responsibility is the preservation of monuments within the Sassi and throughout the region of Basilicata. This includes the several hundred chiese rupestri, numerous Romanesque and Baroque churches and cathedrals, many monasteries and convents, and all related ecclesiastical structuresall off which are built or carved from local stone. He spoke to us this day and showed us examples throughout the Sassi of stone stabilization and restoration processes.

He spoke in more detail of the natural patination of the stone, i.e., the hardening of the outer 1mm of surface into a protective hard skin that results from a SLOW weathering of the stone. Moisture works its way from the interior to the surface of the stone and dries there leaving salt that calcifies stone making it harder. A fast-forming efflorescence of salts, however, is bad for the stone because, La Fratta explains, the formation of salt crystals can break up the stone much the way water does when it freezes inside stone. The

Figure 17. Biagio La Fratta lecturing to the group.

Arc Boutant Historic Preservation ProgramSummer 2002

slow-formed protective patina helps ward off erosion, but erosion can still occur, and when it does, it eats behind the patina, leaving islands or pedestals of hard patina that eventually fall off. The newly exposed stone surface is vulnerable to decay as was the original surface when first excavated. If the erosive conditions subside, however, a new patina can form.

To stabilize the tufo stone itself, the Soprintendenza practices patching, stone replacement (cuci-scuci), and occasionally structural reinforcement. Concurrent with these operations, however, the practitioner identifies the cause of the problem and corrects it if possible. The first of these stabilization methods, patching, is done when erosion is active (i.e., the patina has eroded away) yet at least two-third of the stone block remains (i.e., it is still structurally secure). In this case a malta or cottapesta is applied to the surface, replacing eroded stone. Cottapesta, like malta, is a paste of tufino (tufo powder), lime, and water, with the added ingredient of crushed terra cotta as a strength-providing aggregate. The advantage of this material is that it is chemically close to tufo and therefore acts similarly. Most importantly, it allows for water to pass through it. Though used in the past, cement is no longer an approved material for patching. Not only is it harder than tufo and chemically dissimilar, therefore not providing a strong bond, but it forms a moisture barrier. The problem with this is that it disallows the stone to breathe: moisture inevitably gets trapped behind it and erodes the stone, leaving the cement patch pedestalled. The cottapesta method is considered to be old-fashioned and is used less now that cuci-scuci (discussed below) has developed).

The traditional application of lime paint (calce) as a protective, sacrificial surface is also employed by the Soprintendenza. Historically, it was used inside and outside Sassi structures and offered the additional benefits of disinfecting spaces and providing bright reflective surfaces that amplified the low-light levels of the caves.

When erosion exceeds the effectiveness of patching, cuci-scuci is performed. This is the current, favored treatment of stone blocks one-third eroded or more in a constructed wall. It involved the removal of a damaged block and replacement with a newly quarried one, though some private practitioners replace even slightly eroded stones. For La Fratta and many others, the appearance of new blocks next to old ones brings awareness of the sense of history mixed with the current reuse of the Sassi.

A final method of stabilization is steel injection. This is the process of drilling holes in the stone, inserting steel rods, and injecting cement around the rods. Although this process is generally frowned upon (especially when indiscriminently used), sometimes even La Fratta uses is for lack of alternatives. This is especially the case for fissures in monolithic walls or ceilings. When he applies this method, however, he does so in calculated way. This conservative strategy was not followed after the 1980 (big) and 1990 (small) earthquakes: people pierced holes all over the Sassi adding steel rods with no real study of how and where to do so. Problems that can be introduced with this method are: the weakening of the remaining stone due to piercing, the rusting and spalling of steel, and the introduction of cement, some of whose problems are listed above.

La Fratta also discussed the three phases of the Sassi preservation program and the political processes behind Sassi zoning, preservation regulation, and selection of preservation projects and funding.

Figure 18. Efflorescence of salts on the surface of a wall.

Arc Boutant Historic Preservation ProgramSummer 2002

Fresco restoration, Palazzo Pomarici

Demonstration by Dott.essa Rita Padula and colleagues, July 12, 2002

Trained at ICCROM (UNESCO's school in Rome for the training of conservationists), Rita Padula has the opportunity to know intimately the Sassi's treasure trove of frescoes. She and three colleagues (Maristella Tarantino, Grazia Balice, and Mariella Monteleone) have formed a working team that is asked to do most of the major mural conservation work here. We were fortunate to be invited to see the team in action at Palazzo Pomarici located on the edge of the Civita and overlooking Sasso Caveoso.

Adorning the ground floor public rooms of the palazzo are beautiful frescoes dating from the late 1700s when the palazzo was originally built (as a single-story structure). Three rooms have extant portions of frescoes: one is a floral frieze, a second (the best preserved) shows various hunting scenes, and the third is also figurative with a portrait of a lady and what appears to have been the location of a male portrait (now missing) flanking the other side of the doorway. A later owner in the 1800s added a second floor, added a grand staircase in the courtyard, and transformed the former elegant ground floor rooms into service rooms (e.g., kitchen). At this time, the frescoes were much damaged by nails hammered into them (e.g., for drying foods). By the early/mid-1900s, the entire palazzo was inhabited by numerous poor families, each occupying one room. After the transfer of the population to new housing, the national government became the owner of the building. Following the 1980 earthquake, sloppy, detrimental restoration of the building was carried out by the government with the insertion of steel rods and injection of cement. This process not only coated the frescoes with cement slurry, but salts from the cement have been collecting on the surfaces of the frescoes and causing further damage. Following this "restoration," the building was entrusted to the city, which in turn has rented space upstairs to a private corporation.

Figure 19. Comparison of cuci-scuci wall treatment to untreated wall above.
Figure 20. Evidence of stone blocks replaced by cuci-scuci.

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The level of fresco conservation being carried out by Padula and her team is minimal: cleaning and consolidation. Cleaning, which mostly involves the removal of cement slurry, is done gently with alcohol. Consolidation is more complex. It requires the reattachment where necessary of blistering paint. In most cases, a gluey, organic malta is injected behind the pigment; but where the intonaco support is spalling and the paint is turning to powder, the affected area is impregnated with toxic resin to reconstruct the ensemble.

These are not true frescoes painted onto wet plaster and are therefore less durable. Once consolidated, the artists fill-in and augment colors using watercolor paints. In this way, if later restorers believe that these color choices are wrong or if the pendulum swings in the direction of not adding color, this work can be removed with a damp sponge. The whole process will probably have to be repeated in 20 years.

In-progress preservation decisions and tactics

Lecture and fieldtrip conducted by Dott.essa Architetto Antonella Guida, July 15, 2002

Documented by Chad McPhail

Architetto Antonella Guida walked us through her in-progress project of turning a large sector of Sasso Caveoso into the elegant Hotel Sant' Angelo. Viewing the unfinished project, she explained how and why certain practices were implemented during (re)construction. Building and adapting the ancient structures of the Sassi to contemporary living is challenging. The excavation of caves and addition of buildings one on top of the other over the centuries has left a delicate, sometimes precarious, structural web. Guida has learned through experience that when this web is shaken or alteredas one must do in such a dramatic renovation project as thisit may threaten collapse and require the installation of emergency reinforcements (see fig. 24).

Figures 21­23. Palazzo Pomarici frescoes being cleaned and consolidated (see also fig. 7).

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Current trends and the newfound love of the Sassi have led to fashionable design choices that are not necessarily historically consistent but that redefine the beauty of the Sassi structures with contemporary aesthetics. Seen in the majority of recent Sassi preservation projects (including the Hotel Sant' Angelo), an example of this fashion is the decision not to paint the interior of vaults with white lime paint but to leave them the natural stone color, a vista. Instead, the stone is coated with clear, chemical sealant to prevent the stone from powdering. This sealant claims to allow the rock to "breathe," letting moisture out while preventing it from penetrating into the wall. Intonaco, a lime-plaster slurry, coats the walls throughout the project to protect the stone and to give a clean and consistent look to the hotel walls. Guida feels that the more historically consistent intonaco allows the stone to "breathe," much like the clear sealant.

Final discussion and remarks

Discussion with Dott.essa Dorothy Zinn, July 15, 2002

Concluding our program, Dott.essa Dorothy Zinn, professor of anthropology at the Universita di Basilicatà, invited us to her restored Sassi house for refreshments and reflections on the experience of the program. Due to Chad's imminent departure, the discussion was brief. Zinn's objective anthropological perspective as well as her subjective experience in the renovation of Sassi structures (both her own home and the development of a beautiful new hotel, the Locanda San Martino) were useful comparisons to our own inside/outside perceptions of the preservation process taking place here.

Figure 24. Support for natural stone vault and new buttress wall to the left to counter the threat of structural collapse in the Hotel Sant' Angelo project.

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La Chiesa della Madonna delle Virtu (II)
Figure 25. Chad McPhail and Antonella Guida at the Hotel Sant' Angelo construction site.

Figure 26. Chad McPhail, Biagio La Fratta, and Nunzio Paolicelli in front of the altar at the Madonna delle Virtù.

Figure 27. South facade of the Madonna delle Virtù.

Figure 28. Interior of the Chiesa di Sant' Antonio Abate with the altar original to the Madonna delle Virtù.

Description and historical background of the church

The Chiesa della Madonna delle Virtù is located in the Sasso Barisano along via Fiorentini, the only paved road in the Sassi. According to composer and symphony conductor Nunzio Paolicelli, the church's guardian, it was constructed in 1895. This is an approximate date based on a document owned by the Contraternità di Gésu Flagelato (to which Paolicelli belongs). The document dates from 1900 and mentions the church as already having been built. Although the somewhat clumsily executed backdrop for the church's altar is original, the very finely executed extant altar itself is not original to the building and dates to ca. 1610 (see figs. 26, 30). It came from the 17th-century church of the ex-Ospidale San Rocco. After the separation of church and state at the time of Italian unification (1861), the hospital chapel was deconsecrated, and the Confraternità di Gesu Flagelato (custodians of San

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Rocco and the Madonna delle Virtù) moved the altar to this church. Meanwhile, the original 19th-century altar from the Madonna delle Virtu has been discovered in the tiny chapel of San Antonio Abate, also on the via Fiornentini and also in the custody of the Confraternità di Gesu Flagelato (see fig. 28).

Except for the document mentioned by Paolicelli, no known records exist of the church's construction or history. We did, however, benefit from an oral history transmitted by memory from generation-to-generation that discusses the construction of the church. Paolicelli's father-in-law, Francesco, has a small carpentry workshop located under the church in a space formerly occupied by a tailor shop (a use, Francesco notes, that is better-suited to this small space than is his carpentry). He explained to us that artisans owning workshops under the current church gave permission for the church to be built above them. It was constructed with very little moneyall donations. Even the priest contributed his money and labor to build the church, for example, fetching water for construction. Francesco spoke of the existence of a book listing all the donations given by the various parish families, but we were unable to see this.

The church is one-story. Its nave consists of two large groin vaults separated by a triumphal arch, which seems to visually distinguish between the sacred area of the church and the worshipers' area. The larger vault is located on the north side, toward the altar. Rising to a lower level, a shallow barrel vault frames each of the four side chapels. The front (south) façade is adorned with sober, classical decoration. Layered pilasters rise to a heavy cornice and continue in simplified form to a raking cornice. The arch over the door is recalled in a round rose window in the pediment. Geometric bas-reliefs, two small sculptures set in niches, urns flanking the pediment, and what appears to be a later addition of a high relief Madonna and child over the door are the only other decor. The most distinctive element of the exterior décor is a scalloping pattern that appears in both positive and negative form. A bell tower on the northwest corner of the nave enlivens the west facade,

Figure 29. West facade of the Madonna delle Virtù showing the three artisan workshops beneath and predating the church.

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while the north and east facades remain very plain (see figs. 27, 29, 31­34, 36, 43, 44).

Except for the lower zone (corresponding with the piliaster bases and below) of the south façade which is faced with a hard stone (such as calcare), the entire exterior has been coated many times with intonaco and painted many times with white lime. The east façade and much of the north façade have been entirely coated with gray cement, probably as a measure to arrest erosion (see figs. 31, 32, 36). In many places, however, thick lichen growth and cement patches obscure much of the original wall surfaces. In many areas of the façade, however, lichen growth allow for a greater understanding of the wall construction. Due to the fact that the lichen growing on the intonaco surface generally proliferate on the horizontal mortar joints beneath the intonaco and grow more thinly on the stone block support, they allow for the coursings underneath the intonaco to be seen. This may be because the stone blocks hold water differently than the mortar or because the mortar joints stand slightly proud of the blocks. This phenomenon is also seen with the cornice elements that project from the facades and are encrusted with lichen.

As with most southern Italian churches, the interior artwork is a combination of paintings and large, three-dimensional, painted, life-like representations of revered saints (see figs. 30, 37). For example, in the Madonna delle Virtù, three paintings fill the altar backdrop, and to the right of the altar is a standing figure of Santa Lucia (the patron saint of eyes) holding before her a platter with her realistically portrayed eyes, her iconic symbol. Other three-dimensional saints are framed in glass and wooden boxes. The interior wall painting is a sober tan color with white and ochre

Figure 30. Interior east wall showing altar paintings and polychrome sculpture of Santa Lucia. Note also the music stands belonging to Paolicelli's orchestra.

Figure 31. Urn adorning the upper left corner of the south facade; scallop pattern.

Figure 32. Pilaster, capital, cornice, and inverted scallop.

Figure 33. Detail views of three east facade sculptural elements: 1) recent high-relief Madonna and Child over the door; 2 and 3) niche sculptures to the right and left of the doorway.

Figure 34. Interior east wall (southern side), barrel-vaulted chapel, and triumphal arch (left).

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Arc Boutant Historic Preservation ProgramSummer 2002

trim and a gray, faux-marble base. We identified at least three layers of wall coating representing three successive decorative schemes. Modern, stained glass windows display Christian symbols. The probable original brick floor has been replaced with terrazzo tiles.

The reason that we add the suffix "(II)" to the name of this church is to distinguish it from a Byzantine rock church with the same name that is located nearby. Making it stand out from other churches is its current use as a rehersal space for Paolicelli's orchestra. Even when not rehersing, the band's presence is established through the use of confessionals as storage space for tubas and other large instruments (see figs. 30, 44).

Figure 35. East facade of the church. Lower left portion coated with cement.

Figure 36. Clothed, 3D, polychrome saint in a cabinet: typical southern Italian church artwork.

Figure 37. Chad McPhail studying the roof terrace.

Figure 38. Sample of Chad's working sketch dimensioning and analyzing the terrace.

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Analysis and Treatment of Physical Conditions

All analyses were made through visual inspection of the building, inside and outside, using rudimentary tools. Chemical and instrumental analyses are only viable when monitored regularly over at least one year's time; we were therefore unable to conduct these. The results of the visual study were mapped onto measured drawings that we made of the building. These graphically represent biological growth (leafy plants, algae, and lichen), degrees of stone erosion, minor and structural fissures, previous interventions, water stains, spalling paint, and unprotected wood. See drawings (figs. 35, 46­51).

The building's main problems are: 1) insufficient structural support to carry the vaults' thrusts, and 2) water drainage problems that lead to erosion, staining, and plant growth. These are described below. The problems interlace. A fissure will trap organic material and water that in turn nourish plant growth whose roots will break the crack wider and introduce water to the inner wall, which will further weaken the stone and so forth (plant growth on figs. 31, 32).

Arch. La Fratta generously provided workspace for us in the drafting studio of the Soprintendenza per i Beni Ambientali ed Architettonici. Here, we were fortunate to be befriended by Ida Guida, artist and draftsman for the Soprintendenza. She greatly facilitated and enlivened our work and our stay.


We first identified a large fissure in the exterior of the west wall near the north façade (fig. 40). It had been previously patched with mortar or cement but had reemerged. The question was if it were superficial or if it went all the way through the wall (passante). In the first case, it could be repaired with cuci-scuci. In the second case, it would mean that the façade is falling forward and will need to be reattached to the building using the steel rod and concrete injection technique. A tie-rod passing through the entire sidewall would only be necessary if the whole building were breaking up and needed to be consolidated. Upon inspection inside, we saw not only that the fissure is indeed passante (figs. 41, 44) but also that it has a mate passing through the east wall in the same location. This confirms that the façade is indeed falling forward and separating from the church.

Likewise, the wall above the interior triumphal arch appears to have a number of passante cracks in it (fig. 42). Their being dirty is an indication that the cracks are old and therefore not actively occurring. Although not presently moving and therefore in equilibrium, these cracks are weak points that would be vulnerable in an earthquake, which was probably a cause of them. To correct this problem, a tie-rod is needed to cross through this arch-wall, cinching the two sides of the church. The outer elements of a tie-rod would be capped with thin tufo blocks in order to hide their presence.

Similar to the fissures in the triumphal arch are a series of passante fissures bisecting the south façade (fig. 43). They, too, appear to be caused by the thrust of the groin vault. They occur in the weakest part of the wall, its pierced centerline. Unlike the rest of the wall, which is solid, this point is weakened by voids: the rose window and the large doorway. It, too, will need to be bolstered with a tie-rod.

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Structural fissures

Passante fissures are indicated on the drawings as M2 (labeled as F7, F12, and F15 on the plan, see fig. 46). In the case of this building, they are probably the result of the thrust of the vaults being too great for the walls and piers to support, a condition exacerbated by seismic activity.

Intervention: We recommend the insertion of metal rods treated for rust-prevention through all four exterior walls to act as a tension ring and through the central arch. This measure will counteract the outward thrust of the vaults and the resultant splaying of the walls. The alternative would be the augmentation of the supporting walls by, for instance, buttressing. As this method would drastically alter the design of the church, however, internal tie-rods are preferable.

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Superficial fissures

Superficial fissures are identified as M1 (labeled as F1­F6, F8­F11, and F13­F14 on the plan, fig. 46). These small cracks are numerous and result from building settlement and seismic activity. Most of these occur in the non-structural walls infilling the barrel and groin vault openings. Since these walls carry no load other than their own weight, these cracks do no compromise the building's structural strength in general and are therefore not worrisome.

Intervention: We recommend that smaller cracks be repaired with malta. Mortar joints affected by larger cracks should be repointed. In more extreme cases, the surrounding blocks should be re-laid.

Figure 39. Fissure over clerestory window.

Figure 40. M2 fissure on the west facade announcing that the south facade is breaking away from the building.

Figure 41. The same M2 fissure (of fig. 40) passing through to the church's interior.

Figure 42. Fissures in the triumphal arch.

Figure 43. M2 fissure bisecting the south facade through the rose window and doorway.

Figure 44. Broading view of the fissure illustrated in fig. 41. (This confessional houses tubas.)

Figure 45. M2 fissure (the same illustrated in fig. 43) passing through to the interior of the south wall.

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Figure 46.

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Figure 47. Legend for drawings
Schedule of Interior Problems (see Plan, fig. x)


F1 M1 fissure on north wall above doorway

F2 M1 or possible M2 fissure through west wall. May be a symptom of north wall separating.

F3 M1 fissure on upper west wall along stained glass window

F4 M1 fissure on ceiling above stained glass window

F5 M1 fissure on upper north wall

F6 M1 fissure on upper north wall

F7 M2 misure through wall and arch. Symptom of east-west building separation.

F8 M1 fissure on west wall. Possibly the corresponding fissure to F2 on the east wall, which together would indicate separation of the north wall from the structure in response to the thrust of the vault

F9 M1 fissure on upper east wall along stained-glass window.

F10 M1 fissure on upper east wall

F11 M1 fissure on vault along center

F12 M2 fissure through eat and west walls. Symptom of separation of the south wall from the structure in response to the thrust of the vault.

F13 M1 fissure on lower south wall

F14 M1 fissure in corner of south and west walls

F15 M2 fissure bisecting wall through rose window and doorway. Symptom of east-west splaying of vault.

Water Damage

W1 Exterior water infiltration along lower wall. Symptom of leaks( )from sides or above.

W2 Exterior water infiltration on vault. Symptom of leak(s) from above, perhaps where clogged drainpipe connects to building.

W3 Exterior water infiltration along entire western wall. Symptom of leak from side or above.

W4 Exterior water infiltration on ceiling. Symptom of leak(s) from above.

W5 Capillary action and external infiltration along entirre lower eastern wall. Symptom of humidity from below and from ground to the east.

W6 Exterior water infiltration on vault. Symptom of leak(s) from above. Perhaps where clogged raingutter is located.

W7 Capillary action rising through floor. Symptom of humidity from below.

W8 Capillary action rising through floor. Symptom of humidity from below.

W9 Exterior water infiltration on vault. Symptom of leak(s) from above. Perhaps where clogged drainpipe connects to building.

W10 Capillary action along lower section of wouthern wall. Symptom of humidity from below.

W11 Capillary action above water basin. Symptom to constant adjacent humidity.

W12 External water infiltration on upper section of western wall. Perhaps from collection of water on roof terrace due to clogged drains.

Other Notations on the Plan

M1 Metal object imbedded in vault

M2 Metal object imbedded in vault

C1 Cement patching in corner

C2 Cement patching in corner

Erosion, 0.5­2cm depth
Erosion, 2­5 cm depth
Cement coating and patching
Other coating and patching materials
Weathered paint / unprotected wood
Metal objects
M1 Superficial fissure
M2 Structural fissure

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Figure 48.

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Figure 49.

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Figure 50.

Arc Boutant Historic Preservation ProgramSummer 2002

Figure 51.

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Drainage problems

A variety of drainage problems (blocked drains, capillary action (rising damp), water infiltration) account for many of the Madonna delle Virtù's other problems (growth of vegetation, erosion, and staining and spalling of interior surfaces).

Unmaintained drains

Unmaintained rain gutters and downspouts collect organic matter and prevent proper drainage. See figures 52­54 to see the extremity of this third condition in which pigeon guano completely fills the water drains on the west façade (and mounds under the bell, whose only current use is as a perch for pigeons (fig. 52)). Rain washes the ever-increasing amount of guano from the roof surfaces into the completely clogged gutters and drains. As a result, water does not exit but remains trapped in this dense organic matter and is absorbed by the surrounding stone. The algae growth in these areas (see figs. 61, 64) attests to the presence of moisture.

Interventions: In the short term: clean out drains and maintain them. Discourage pigeon use of campanile and roof terrace with netting. In the long term, replace metal gutters and downspouts with terra cotta gutters and external terra cotta downspouts (for historical accuracy). Patch areas where current internal downspouts are located (fig. 61).

Figure 52. Mounds of guano in the campanile under the bell.
Figure 53. Gutter on roof terrace filled with guano.
Figure 54. Top view of downspout filled with guano.

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Water infiltration

The presence of lush weeds along the east façade, the staining and spalling of paint on the interior of this wall, and the fact that the exterior of this wall was coated with cement which does not breathe and forces the wall's moisture into church all attest to water infiltration resulting from a drainage problem (figs. 55, 63). Infiltration also occurs along fissures and blocked drains that collect moisture and release it into the building, as described above (fig. 57).

Interventions: In the short term: dig a drainage trench along the east façade to provide a dry airspace along this problem area and to channel water away from the structure and toward the front of the church. Clean, repair, and re-seal adjacent cistern in the event that it is leaking water onto the church. As described above, clear out and maintain rain gutters and down spouts. In the long term: remove impermeable cement coating on eastern façade.

Figure 55. Southeast corner of building: cement coating and lush plant growth.

Figure 56. Water infilltration and staining in chapel ceiling under roof terrace (whose water egress is blocked with guano).

Figure 57. Water infilltration and staining in the west wall behind a clogged downspout.

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Capillary action:

A source of groundwater appears to be located under the structure. It results in the rising of moisture in the walls and floor by capillary action. The results of this event can be seen in the moisture problem occurring in terrazzo floor tiles in middle of church, in the erosion of stone (evidenced by the layering of stone patches) in the lower 1­2 meters of all exterior walls (seen on the south façade above the harder calcare veneer covering the base of the wall), and in the staining and spalling of paint in a zone 1-2 meters along the base of the inner east and south walls (this same zone along the north and west walls occurs in the workshops below the church). (See figs. 58­61.)

Interventions: Although appearing to be a continual problem, capillary action may not be so grave as to demand immediate action. Regular repair (patching and painting) seem to be maintaining the structural integrity of the wall, so we recommend the continuation of this passive system. Should the problems increase and the integrity of the walls decrease, a drainage system may be introduced (for example, trenching along the south façade) and a vapor barrier may be introduced below the walls. This may be accomplished with injection of resin or by making a horizontal cut through the base of the wall and passing a vapor barrier through this.

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The result of water problems and the cause of more problems is vegetation. This falls into two groups:

Leafy plants with invasive roots

There are three causes for the growth of these plants on the building: 1) cracks in and along walls that allow organic material to collect and water to penetrate (figs. 31, 32); 2) earth built up against the exterior walls, especially along the east side, that nourishes plant life (figs. 55, 63); 3) unmaintained rain gutters and downspouts that collect organic matter and prevent proper drainage. See figures 52­54 to see the extremity of this third condition in which pigeon guano completely fills the water drains on the west façade (and mounds under the bell, used only by pigeons).

Interventions: In the short term, remove plants from cracks, water drainage areas, and along sides of church (i.e., all plants). Clear out gutters and downspouts. Spray ground along east side with herbicide. Clear out gutters and downspouts. In the long term, repair cracks and see interventions for drainage problems.

Several varieties of lichens, algae, and mosses

There are, again, three causes for this growth: 1) moisture trapped in stone, mortar and old patching attempts; 2) cracks in and along walls that allow organic material to collect and water to penetrate; 3) moisture collecting on ledges and dripping from poorly maintained rain gutters and downspouts. These plants break down the stone surface and therefore contribute to erosion. Their removal is necessary.

Interventions: In the short term, remove this growth with a wire brush or metal blade and repeat as often as necessary. Clear out gutters and downspouts. In the long term, repair cracks. Additional relief of the lichen problem will be attained by resolving drainage problems (see interventions for drainage problems).


Stone erosion is caused by a breakdown of the material as a result of human contact (scratching, rubbing, and diggingas seen near the front door and in the graffiti along the exterior wall to the left of the door), natural elements (wind, direct contact with rain, external infiltration, rising damp (capillary action)), and organic growth.

Interventions: Some of the causes of erosion can be addressed, for example, removal of organic growth (described above) and correction of external infiltration (see intervention for drainage problems). If rising damp is thought to be serious enough, a vapor barrier may be introduced below the walls, as described above. To repair existing erosion, clean eroded area, fill with malta or cottapesta, and paint entire exterior with lime paint as the exterior has been treated in the past.

Figure 58. Spalling of intonaco due to rising damp.

Figure 59. Staining and spalling of paint due to capillary action in the south wall. Note the same effect occurring above the water basin.

Figure 60. Water-stained terrazzo flooring.

Figure 61. Lower 2 meters of the exterior west wall patched and coated many times to repair the damages of rising damp.

Figure 62. Cement repair behind a downspout: proof of drainage problems previous to the current ones.

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Exterior coatings and patching

Both cement and limestone-based patching materials have been used to repair and protect the wall exteriors. These all need to be analyzed for effectiveness.


The extensive use of cement to coat the east façade and parts of the west and north façades suggests that these areas have been plagued by moisture problems and erosion. The use of this impervious material, however, causes further damage by trapping water in the stone. This result is witnessed by water stains on the interior walls (cuci-scuci).

Intervention: Remove all cement coating and patches and fill eroded surfaces with malta. If erosion exceeds 1/3 the depth of the stone, replace the stone.

Malta, intonaco, and other coatings and patching

Although not hazardous to the stone support, the application of these permeable products has been messy and haphazard. In some areas, they fail to protect the tufo, while in others they are very effective.

Intervention: We suggest continued patching and filling with such tufo-based products as these (i.e., not cement) because they have been proven to be effective and are historically consistent with the building and the Sassi in general. We also believe that the lime-painting of the church's exterior should also be maintained, as it appears to have been done in the past.

Interior finishes restoration:

It is the intention of the Soprintendenza to "restore" this church to its original appearance. To do this, additional research will be necessary to establish the original appearance of the interior. This is always a problematic endeavor as the building cannot entirely step back in time and because such intentions attempt to negate history and time. They invariably reflect contemporary tastes more than they do historical ones. Not only would the wall treatments change, but the terrazzo floor would need to be replaced, and the re-shuffling of altars would need to take place, thereby impacting several more structures. Though weathered and peeling, the wooden front doors are structurally sound and can be reused after removal of current paint, treatment for fungus and pests, filling of cracks, and repainting. We recommend that no interior work be accomplished until the structural and drainage problems be corrected.

Figure 63. Southeast corner of the building. Compare the original and maintained intonaco/calce coating to the gray cement portion.

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Plan of attack (in order of urgency and in order of degree of intervention)

1. Remove bird droppings from drainage system and bell tower area

2. Remove leafy plants from fissures in building

3. Install tie rods through outer walls and through inner arch

4. Remove plants from east side of building and dig drainage trench

5. Repair cistern

6. Remove cement wall coating

7. Fill fissures and repair masonry as needed

8. Remove lichen

9. Fill eroded areas with malta and paint exterior walls with lime

10. Replace rain gutters and downspouts in terra cotta.

11. Determine original interior decoration

12. Repair front door

13. Restore or reproduce flooring, wall ornamentation, and altar.

Figure 64. Northeast corner of the building. Some parts coated with cement.

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Social Acclimatization

As mentioned above, being a small group this year had cultural advantages. We received several invitations to dine with local residents. They took it upon themselves to expand our education with knowledge of the regional cuisine, called cucina lucana. This involved many courses of food and wonderful discussions of local produce and food preparation. After a day at the beach of Metaponto, Anna Mastrogiulio invited us to a wonderful restaurant, Il Borgo Antico, in her hometown of Pisticci. Anna and Nicola Ruscigno, owners of Casa di Lucio, invited us to dine with several of their friends at a restaurant they own, the Alma Loca. Of particular significance was Ida Guida's invitation to dine at her home. Every course, side dish, and beverage was grown and prepared by her and her family.

Figure 65. Ida Guida in her kitchen entertaining our group for dinner.

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Personal Profiles

The director and founder of Arc Boutant Historic Preservation Program, Anne Toxey is a restoration architect and architectural historian. She is currently a doctoral candidate in architectural history at University of California, Berkeley. Her dissertation topic addresses the impact of preservation of the Sassi on the city and province of Matera. She also co-directs a museum exhibit design firm (Toxey/McMillan Design Associates) with her spouse, Patrick McMillan.

Arc Boutant 2001 participant, Chad McPhail, is originally from Orange County, California. He is currently working on a BFA in Interior Design at Parsons School of Design in New York City. In 1999/2000 he worked as a gallery assistant and helped to renovate Smack Mellon Studios, a contemporary art gallery located in a former spice factory in Brooklyn. In the summer of 2001, Chad worked with La Sabranenque, a French restoration organization. Here, he learned medieval stone carving techniques and helped restore the Chateau de St. Victor La Coste near Avignon. Currently, he is entering his final year at Parsons and is working for the design firm, Mr. Architecture + Decor. After completion of his thesis in May 2003, Chad hopes to continue his studies with a graduate degree in Historic Preservation and to live and work in Italy.