140P2021R0055-0004_Att04-2004SecondBankStoneSurvey-FinalReport_040601_0004.pdf

THE PENNSYLVANIA BLUE PROJECT

Documentation and Conditions Survey of the Exterior Marble Masonry

THE SECOND BANK OF THE UNITED STATES

INDEPENDENCE NATIONAL HISTORICAL PARK

PHILADELPHIA, PENNSYLVANIA

Prepared by:

The Architectural Conservation Laboratory and Research Center 051 Duhring Wing University of Pennsylvania

Frank Matero, Director, ACL John Hinchman, Supervising Conservator (2003) Guy Munsch, Supervising Conservator (1999) Kerry Johnston, Project Assistant A. Elena Charola, Conservation Scientist

Prepared for:

The National Park Service Independence National Histoical Park Philadelphia, Pennsylvania

June 2004 Table of Contents

Acknowledgements ...........................................................................................................................i

1.0 Introduction

2.0 Project Overview

2.1 Phase 1 (1999)

2.2 Phase 2 (2003)

3.0 Documentation and Archival Research

4.0 Construction and Conservation History

5.0 Marble Decay: An Overview

6.0 Existing Conditions

6.1 Condition Recording and Assessment: A Conservator’s Guide

6.2 Conditions Recorded: Phase 1

6.3 Conditions Recorded: Phase 2

7.0 Condition Assessment Drawings

8.0 Material Analysis

8.1 Analysis Summary

8.2 Sample Locations

9.0 Recommendations for Future Phases

10.0 Bibliography

10.1 Published Sources

10.2 Unpublished Sources

11.0 Appendix

11.1 Appendix A. Guidelines

11.2 Appendix B. Budgeting: Hours Allocated by Task

11.3 Appendix C: Masonry Conditions Glossary

11.4 Appendix D: Overview of 1999 Database of Conditions

Index

Acknowledgements

The completion of all phases of the exterior masonry conditions assessment of the Second Bank of the United States would not have been possible without the dedicated efforts of many.

Graduate and post-graduate interns from the Historic Preservation Program at the University of

Pennsylvania committed a tremendous amount of time and energy to complete the conditions survey, archival research and preliminary analyses. Thank you to Lori Aument, Elsa Bourguignon, Catherine Dewey, Claudia Harbert, Diane Jackier, Margaret Newman, John Glavan, Lauren

Hegerty, John Howard, Kerry Johnston, and Sophia Middlebrook.

This project has been developed through the Cooperative Agreement between the National Park

Service, Independence National Historical Park and the University of Pennsylvania. Members of both organizations have contributed to the coordination, implementation, funding and continued research into preservation issues at the Second Bank of the United States. At the University of

Pennsylvania, Frank Matero, Chairman of the Graduate Program in Historic Preservation, A.

Elena Charola, Guy Munsch, John Hinchman, and Kerry Johnston have been integral to the participation of the University. At the National Park Service the tireless efforts of Bill Brookover, Doris Fanelli, Charles Tonetti, Todd Hart, Karen Stevens and the staff at the Lowell Conservation

Center have helped guide the development of the project.

Technical assistance was provided for specialized segments of the project. Cyra Technologies provided laser-scanning services in 1999 as a demonstration of newer technologies that could be incorporated into the survey methodology in the future. The architecture firm of Dan Peter Kopple and Associates also provided support in 1999 with CAD rendering assistance and welcomed the students into their office as an impromptu on-site studio.

i

1.0 Introduction

Independence National Historical Park (INHP) is home to several of the most significant monumental public buildings of the early American republic. Three of these buildings, the First

Bank of the United States (1795-97), the Second Bank of the United States (1818-24) and the

Merchant’s Exchange (1832-33), span a period when Philadelphia served as the nation’s capital, and then as its financial and cultural center. Reflective of this history, these three buildings physically embody and communicate the wealth and promise of the new nation through their developed academic neo-classicism and then unprecedented use of monumental masonry construction with local stone resources. The preservation of these buildings as architectural icons of American federalism and finance was formally recognized with the establishment of

Independence National Historical Park in 1959.

The increasing importance of monumental masonry construction in establishing the various styles and modes of American building began in the early nineteenth century with the revival of Greek classicism. White marble, cut and assembled to evoke the architectural prowess of the ancients, was promoted as the material of choice. The massive and easily accessible beds of Pennsylvania marble, also known as Pennsylvania Blue or Montgomery County marble, quarried just north of the city, was an important regional building stone for public and domestic structures during the first half of the nineteenth century. Benjamin Latrobe's Bank of Pennsylvania (1798-1801, demolished c.1870) and William Strickland's Bank of the United States (1818-1824) (Fig. 1) were among the first monumental stone structures to showcase the area's famous marble. On May 8, 1811, Benjamin

Latrobe delivered an anniversary oration before the Society of Artists of the United States in

Philadelphia, extolling the importance of the city's precious marble resources:

The beautiful marble with which this neighborhood abounds, and the excellence of all other building materials, give to Philadelphia great advantages in this branch of the fine arts. The first building in which marble was employed as the principal material of its front, is the Bank of the United States…Only one year after its completion the Bank of Pennsylvania was built…such a building so different from all that had preceded it in form, arrangement, construction, and character…[that] the style of this single building has given to the Philadelphian architecture, even in our plainest brick dwellings, a breadth of effect and response vainly sought in other cities.

By the middle of the nineteenth century, poor performance of the stone and improved transportation systems that increased the availability of other marbles from Maryland, Massachusetts and Vermont all contributed to the demise of Pennsylvania marble as a building stone. Once a building stone acquires a record of poor weatherability and is no longer commercially viable, there usually is little motivation for continued use of the material. In most cases, it is only years later through renewed conservation studies of deterioration and treatment of historic buildings that information about the properties and performance of specific building materials and technologies is updated or reevaluated. In the case of Pennsylvania marble, its short-lived fame and restricted use have resulted in limited scientific study of its deterioration and conservation.

In December 1994, in response to observed stone failure at the Second Bank of the United

States, a preliminary assessment of the exterior masonry and characterization and analysis of the stone was initiated by the National Park Service (INHP) and conservator Virginia Naudé. This led to temporary protection and emergency stabilization of critical areas of the entablature for public safety. Historically there has been periodic dimensional loss of the marble through spalling on the columns and along the entablature. Additionally, in unsheltered areas of the ashlar walls, many stones display a deep pattern of loss through contour scaling of the stone faces. (See

Section 3.0 – Construction and Conservation History)

In 1996 the Architectural Conservation Laboratory (ACL) of the University of Pennsylvania in conjunction with Independence National Historical Park (INHP) began a program of stone characterization and physio-mechanical testing of potential consolidation methods for the

Pennsylvania Blue marble.1 In 1999 following these initial studies, a multi-phased conservation plan was developed and initiated with the Park beginning with the preparation of a detailed CAD-based survey of the exterior masonry conditions and the compilation of a history of past repairs and treatments to the building.2 Phase 1 of the survey began with the north and west elevations in 1999. Also during this period, preservation staff from the Northeast Cultural Resources Center

Building Conservation Branch of the National Park Service executed pilot mortar repairs. The exterior masonry conditions survey was brought to completion during Phase 2 of the project, surveying the south and east elevations in 2003. Presently, all of the exterior masonry has been carefully inspected and the conditions recorded, digitized drawings produced, and preliminary assessments formulated. Data gathered from the exterior masonry survey will be used in preparation for GIS-based diagnostic assessment and remedial and preventive intervention, beginning with the portico columns.

The National Park Service now has the opportunity to provide the most comprehensive research on Pennsylvania marble and its conservation due to the prominence of these three monumental buildings at Independence National Historical Park. While each building possesses distinct conditions that must be recognized individually, there is much that can be gained by addressing the full range of variations in the use, performance, and weathering of the marble and by comprehensively surveying and cataloguing the conditions across all three buildings. In addition, 1 Jocelyn Kimmel. “Characterization and consolidation of Pennsylvania blue marble, with a case study of the Second Bank of the United States, Philadelphia, PA” (master’s thesis, University of Pennsylvania, 1996).

a wider testing program can be implemented to evaluate treatments, repairs and preventive measures to address existing damage and minimize future marble deterioration and loss, and to predict areas of the stone predisposed to future failure. This program, named The Pennsylvania Blue Project, has the potential of providing much needed information on the history, use, properties, deterioration and treatment of Pennsylvania marble as used in thousands of buildings found throughout the city and surrounding region.

Figure 1: North Elevation of the Second Bank of the United States, April 2004.

2 Report compiled by Frank Matero, Dawn Melbourne and James Toner. “Construction and Conservation History of the Second Bank of the United States,” 1996, Historic Architect’s File, INHP.

2.0 Project Overview

2.1 Phase 1 (1999)

The development of a conservation plan for the Second Bank of the United States will require several phases of research and investigation (some already completed) including archival documentation, condition survey and recording, laboratory and field analysis, and testing of proposed treatment interventions. Components of this research have been underway since 1986;

however, Phase 1 of exterior conditions recording began with a detailed survey of the marble masonry of the north portico and façade (the main entrance to the Second Bank from Chestnut

Street), and the full west elevation. The survey was conducted from June 7 through July 16, 1999. A total of six graduate and post graduate interns from the Architectural Conservation

Laboratory of the Graduate Program in Historic Preservation at the University of Pennsylvania conducted a complete investigation of both elevations with the use of movable scaffolding and 60’ and 45’ high lift cranes with extending booms.

Rather than recording all surfaces with rectified photographs to survey conditions, the existing

Historic American Buildings Survey (HABS) drawings from a 1939 survey were digitized and refined. The dimensions of architectural features and joint lines were verified in the field and corrected or added as needed. Once the coursing and stone dimensions were finalized, the base drawings were used to record detailed conditions of the masonry. Only critical areas that displayed complex deterioration patterns (e.g. column drums) were digitally photographed during the survey for later comparison.

Teams alternated between recording conditions in the field and digitizing those conditions in

AutoCAD over the new drawings. During the six-week field school, all elevations of the portico including the columns, pediment, ceiling, flooring, and stairs as well as the entire west elevation were surveyed and digitized. Two interns continued for a three-week period beyond the field school to check and complete the survey drawings.

In addition to the field survey and subsequent drawings, a searchable database in Microsoft

Access, a website, and report were created. For the database, each stone on the drawings was assigned a number, and each condition was entered as a separate category allowing the user to find all the conditions for any numbered stone, or to query and determine how many, or which stones have a particular condition. All conditions were eventually imported into ArcView to allow for greater diagnostic manipulation.

A complete set of digital and printed documents from this project (see Section 7 and Appendices) have been submitted to the National Park Service at INHP and the Architectural Conservation

Laboratory at the University of Pennsylvania. All field notes, computer files, and correspondence have been deposited in the Archives at INHP.

2.2 Phase 2 (2003)

The exterior condition assessment was completed in 2003 with a detailed survey of the marble masonry on the south and east façades. Phase 2 of the survey was conducted from June 2 through July 11, 2003 by a total of five graduate and post graduate interns from the ACL of the

Graduate Program in Historic Preservation at the University of Pennsylvania. Movable scaffolding and a 60’ high lift crane with double articulated extending booms were used for recording and documentation purposes. (Fig. 3)

AutoCAD® line drawings from the 1999 survey were modified and adapted to the south and east elevations to be used as base drawings for conditions recording. The drums of the columns were accurately measured while all other joint lines on the ashlar walls, steps, and floor were carefully approximated by eye.

For surveying purposes, the team divided the conditions into five groups and assigned each group to one team member. This decision was made in order to ensure consistency across the survey in an effort to combat against the sometimes subjective nature of conditions recording despite detailed glossaries. All conditions recording of the entire east elevation and south portico including the columns, pediment, ceiling, mutules, entablature, floor, and stairs was completed during the six-week field school. Three interns continued for two to three weeks beyond the field school to begin the digitization process. One intern continued over the course of the fall and winter to complete digitization and lay out the final set of drawings.

Documentation in the form of digital photography was also made during time spent in the field.

When an exemplar condition was found, it was photographed for use in the revised glossary.

Unique conditions and complex deterioration patterns were also photographed, along with construction details that could only be seen with the aid of the high lift or scaffolding. (Fig. 2)

Digitization was a three-step process using Photoshop, AutoCAD, and ArcView software. First, all field drawings were scanned and rectified in Photoshop and then montages were created for each respective elevation or architectural element. The next step included importing these images into AutoCAD, where they were digitized. Scanning and montaging the field drawings and then drawing over them using AutoCAD guaranteed the highest level of accuracy for conditions recording. CAD digitization was completed in October 2003.

While the conditions recorded in Phases 1 and 2 of the survey remained essentially the same

(with some adjustment), the final drawings appear different. This is a result of the decision to use

ArcView beyond its analytical capabilities; it is also useful for displaying and representing data.

Not only does ArcView offer far more colors and hatches than AutoCAD, it is also easier to manipulate and fine-tune the conditions layers. With over thirty conditions represented on any given drawing, it was essential for them to be displayed in as clear and logical a manner as possible.

Using GIS as a part of the digitization process has also allowed the data to be used for future analysis of the stone’s performance and deterioration. ArcView will allow an in-depth study of correlations between conditions to help determine how and why certain conditions appear in certain places over time. Eventually, the GIS software can be used to help predict where future deterioration might occur. Before any analysis can begin, however, all of the 1999 Phase 1 drawings must be ArcView compatible and therefore converted from their current AutoCAD format. Hopefully, this will occur in the near future.

Final layouts of the Phase 2 drawings were made using Adobe InDesign software and then converted into portable document files (.pdf’s) with Adobe Acrobat. The final set was completed

February 2004 and a complete set of the condition assessment drawings and digital files have been submitted to Independence National Historical Park. All field notes, correspondence, and digital files are also archived at the Architectural Conservation Research Center at the University of Pennsylvania.

Figure 2: A view of the capital blocks on the south elevation, July 2003.

3.0 Documentation and Archival Research

Several sources were consulted while searching for specific information on the Pennsylvania Blue marble. Research was mostly conducted at the Independence National Historical Park (INHP) office and the libraries of the University of Pennsylvania.

The majority of the information found came from the files of the Historical Architect at INHP that contain information from state Geological Surveys and student research on the Pennsylvania quarries. A ledger in the collection of INHP from the Henderson Quarry contains a balance of entries of deliveries for the construction of the Second Bank beginning April 20, 1819 and ending

March 16, 1820. The first entry describes a delivery: “April 20, to 38 feet Marble delivered at the prison yard @ 140/100 foot -- $53.20.” The prison yard referred to is the Walnut Street prison formerly located one block southwest of the Second Bank; it was a prison for Tories, prisoners of war, debtors and felons used from 1775-1835. The prison was located on one of William Penn’s original civic squares from Walnut Street south to Locust Street. It has not been determined whether the prison was used solely to stockpile the marble or if prison laborers provided some of the rough finishing of the marble slabs. Subsequent entries in the ledger provide dates and quantities of marble slabs delivered, but contain no additional information.

At the University of Pennsylvania, searches were conducted on Franklin, the library search system. No matches were made for any specific information on Pennsylvania Blue marble or

Marble Hall or Henderson quarries in Montgomery County, Pennsylvania. Due to the time limitations of the first phase of the project, and with the emphasis on recording physical deterioration conditions, additional archival research was not conducted at other Philadelphia institutions such as the Free Library, the Athenaeum, the Historical Society of Pennsylvania or the

American Philosophical Society.

At the INHP Archives, two folders entitled “Construction — Rehabilitation and Restoration /

Second Bank of U.S.” dated October 1964 and January 1965 contain specifications and architectural drawings for the repair work to the exterior marble columns and the platform construction around the bank (see Section 4.0). Although no documents identify exactly what repairs were done to the columns, drawings show that thru-bolts and dowels were to be driven through the columns for stabilization. Four archival boxes containing documents relating to

“Construction Project Records for Second Bank Site Development, 1961-1978” were also examined at the INHP Archives. The majority of documents in these boxes, such as transmittal forms and weekly summary reports, relate to the 1971-1973 restoration of the building which consisted mostly of interior work. The documents also contain information relating to the wrought iron fencing and grates that were installed on the south façade of the building. Within these boxes, however, one document dated October 6, 1969 written by Joe Petrak indicates that, in

1967, Hydrozo “Clearstone” was used to waterproof the exterior marble of the Second Bank. The stone was scrubbed before the treatment was applied. Another document, dated November 10, 1975 mentions re-attaching a portion of an exterior stone column with an epoxy adhesive, although no documents indicate exactly what installation methods were utilized.

Figure 3: Team member John Glavan recording conditions on the columns of the south elevation, Summer 2003.

4.0 Construction and Conservation History3

This section chronicles the construction and restoration of the exterior of the Second Bank including all past remedial interventions and maintenance. The section will start with the building's construction from 1819 to 1824 and proceed chronologically. The majority of primary sources was found while searching the Historic Building File, the Historic Architects File, and the

Photographic File at the Archives of Independence National Historical Park. Most reports were located in the Historic Building File, while most correspondence was found in the Historic

Architects File.

During construction the marble was quarried, cut, and dressed according to traditional stone masonry practices. Prison labor was used for sawing the marble blocks into thick veneer for the facing of the brick masonry building. Financial records indicate that saw blades and sawing sand were purchased for the task.4 Frame saws used for this purpose were similar to iron blade wooden saws, but without the teeth. Wet sand, used as the abrasive, was placed in a groove in the stone. The mason moved the sand back and forth with the saw blade, replenishing the wet sand as needed.5 The slabs were then hauled from the prison to the construction site, where the work was finished. Financial records indicate that the columns were fluted and rubbed at the construction site.6 The marble slabs cut for ashlar siding were also rubbed. The term "rubbing" the stone referred to honing the stone to a smooth surface with either an abrasive sandstone block or a hard rock with wet sand.7 Financial records show that pumice stone was purchased, which could have been used for this purpose.8 No documentation was found describing mortar composition, however the mortar used in 1865 was referred to as "lime cement" which indicates that lime and sand were also probably employed during the original construction.9

Subsequent cleaning seemed to follow traditional stone masonry methods as well. In 1844, William Strickland reported to Collector Judge Blythe that "the whole of the interior as well as the

3 Compiled by James Toner, Dawn Melbourne and Frank Matero, 1996.

4 Robert J. Colborn, "Historical Data," Chapter 2 of "Historic Structure Report of the Second Bank of the United States" (Philadelphia: n.p., 1962), 5, Historic Building File, INHP.

5 Charles McKee, Introduction to Early American Masonry, National Trust/Columbia University Series on the Technology of Early American Building (Washington, D.C.: Preservation Press, 1980), 5, Historic Building File, INHP.

6 Colborn, 5.

7McKee, 30.

8Colborn, 5.

9Superintendent John Rier to Acting Assistant Architect B. Bertly, 26 October 1865, Historic Architects File, INHP.

exterior required a thorough cleansing and repair, particularly in the items of carpentry, masonry, painting & glazing.... The marble columns and architraves of the principle business room required scrubbing with pumice stone, to remove the dust of the years...."10 Although the use of pumice was mentioned for cleaning the interior marble, it is possible that a similar cleaning technique was used on the exterior stone as well. In 1873, Superintendent John McArthur told

Supervising Architect A. B. Mullett that the Ionic carved capitols, fluted columns, molded bases, and antae were rubbed clean as part of an overall project to improve the "large room of the

Custom House."11 No primary source was found identifying what materials were used to clean the stone. Today, the interior marble is in good condition, with the capitals and fluting retaining good detail and little evidence of soiling.

Stone deterioration on the Bank triggered more stone repair in the early 1920’s. Some loose stone was removed from the columns by 1 November 1922. The stone deterioration was considered severe enough for the federal government to request from the Obelisk Waterproofing

Company of New York and the Avron Company of Philadelphia estimates for waterproofing the entire exterior of the structure. The surviving correspondence shows only the estimate from the

Obelisk Waterproofing Company made in 1922.12 The Obelisk Company gained notoriety (and its name) for applying hot paraffin wax on Cleopatra's Needle in New York City in 1885.13

Paraffin has a low melting point, which during hot days causes atmospheric particulates to adhere to the surface. Photographs from 1940 show the building uniformly soiled, which might be explained by the hot wax treatment.14 In 1923, Edward Crane, consulting architect, reported that several pieces of marble had fallen off, especially from the columns. He recommended that the building should be cleaned, repointed, and waterproofed. The use of a waterproof compound

“could do no harm and might prove a real preservative." For cleaning, he recommended that soap and water should be applied with a stiff brush.15

The dark deposits seen in the 1940 photographs suggest cleaning was not pursued, triggering further treatment efforts. In May 1942 the exterior marble was cleaned and waterproofed, but no

10William Strickland to Collector Judge Blythe, 9 December 1844, Historic Architects File, INHP.

11Superintendent of Public Buildings John McArthur to Supervising Architect for the Treasury Department A. B. Mullett, 7 January 1873, Historic Architects File, INHP.

12 President F. S. Condit of the Obelisk Waterproofing Company to Stewardson & Page, Estimate, 31 August 1922, AIA Archives and Library.

13 Erhard M. Winkler, Stone in Architecture. 3rd edition. Springer-Velag: Berlin, 1994. pp 182-183.

14 "Old Philadelphia Custom House" (Philadelphia: n.p., 1947), 2 Historic Building File, INHP. This phenomenon was also observed at Trinity Church, N.Y.C. around the same time period.

15 Architect Edward Crane to Supervising Architect James A. Whitmore, 16 February 1923, AIA Archives and Library.

records were found describing the reagents, tools, or methods used.16 Photographs show that the columns and the ashlar of the south façade were cleaned from the bottom up, with the northern elevation being done at about the same time in a similar pattern.(Fig. 4) The east and west façades were cleaned in sections starting at the southern and northern ends working towards the middle.17 Later reports were more complete with a 1961 report by Grant Simon recommending thirteen different methods for preserving the marble; however, no indications have been found that his cleaning recommendations were followed. Simon wanted the marble cleaned with water and brushes. More difficult areas were to be washed by hand with brushes supplemented with steam pressure at less than 100 psi. He recommended that the most difficult areas be cleaned with the previously mentioned steam pressure and by hand, supplemented with sand. After restoration, the exterior would be cleaned with water, and where necessary, scrubbed with fiber brushes on an annual basis. He discouraged the use of water repellents, detergents, or chemical solutions. Only water was to be allowed.

Marble repairs were to follow specific procedures, and some of them are familiar to contemporary conservators. He recommended the removal and repointing of all defective and loose pointing.

Tapping with a light mallet would reveal any incipient spalls on the columns. (Fig. 5) Any loose or deteriorated marble on the column caps or upper horizontal surfaces could be removed and replaced with “colloidal materials,” presumably a synthetic-based composite repair. No mention was made as to exactly what materials were used. The open seams were carefully cleaned and

Figure 4: South façade, in process of being cleaned, 1942.

16 "Old Philadelphia Custom House," 2.

17 National Park Service, INHP Archives, Photograph Collection, Unaccessioned, Second Bank of the United States, May 1942.

then closed with a filler adhesive and spalled ashlar was replaced by either marble dutchmen or composite repairs.18 Today, yellow patches on the columns are visual indications that organic amended repairs were used to fill the cracks; epoxy repairs were mentioned in later records.

An August 1963 report by Gary Dysert recommended the brush application of "P-56 Brick and

Stone Cleaner" after a successful test on Old City Hall. The test was conducted on twelve square feet of brick and 17.3 square feet of dressed stone at Independence Hall. The two coats were applied, left to stand for a half hour, and then washed off with water and scrubbed with a stiff bristle brush. The chemically active ingredient of the cleaner was identified as ammonium fluoride. According to the records, the `P-56' cleaner produced a white haze on the surface. A solution of sodium bicarbonate was recommended for use to remove the residue. 19 The test was judged to clean without any ill effect to either the stone or brick. There are indications that the cleaner was used on other buildings.

Some care was taken to report deteriorating exterior stone from 1964 to

1965. On 21 January 1964, a fragment of marble fell off the top of the column on the east end of the north façade.20(Fig.

6) In July 1964, Architect Joe Petrak reported that a large area of spalling on the shaft of the northwest column was clamped in place and needed "extensive repairing or partial replacement."21 In

1965, missing panels and terraces were restored to the original configuration using new marble.

He also reported, "some spalling at new marble work due to hard mortar used."22

Figure 5: North portico, column 1, incipient spalling. 1961.

18 Grant Simon, "Report on the Preservation of the Exterior Masonry of the Buildings" (Philadelphia: n.p., 1961), 5-6, Historic Building File, INHP.

19 Gary Dysert, "A Report on the Use of Fluoride Brick and Stone Cleaners" (Philadelphia: n.p., 1963), 1-3, Historic Building File, INHP.

20 National Park Service, INHP Archives, Photograph Collection, Unaccessioned, Second Bank of the United States, 21 January 1964.

21 Joseph Petrak, "Historic Structure Report of the Second Bank of the United States" (Philadelphia: n.p., July 1964), 17, Historic Building File, INHP.

22 Penelope Batchelor, "Census of Treated Historic Buildings" (Philadelphia: n.p., 1982), 5-7, William Brookover's File, INHP.

The January 1964 report of spalling stone preceded the extensive restoration and conservation work performed on the Second Bank that summer. The northern and southern steps, terrace, and cast iron railing were restored to the original design of William Strickland in 1964. Architect Joe Petrak reported that "at the present time cleaning and pointing of the marble is in progress and is being done by the day-labor force. The surfaces were cleaned with fluoride solutions and clear water, and the results were satisfying. "23 Park Architect

Figure 6: North portico, column 1, dimensional loss.

1964. Note fresh loss of upper area in 1961 photograph (Fig. 5).

Penny Batchelor reported that the fluoride solutions were applied with soft bristle brushes and rinsed with clear water.24 Photographs taken in July and August of 1964 indicate the cleaning patterns for only the north and south façades. (Fig.7) For the north façade, the scaffolding was first erected on the eastern side of the portico. The workers started cleaning at the apex of the raking cornice and then proceeded down to the columns and ashlar stones. The scaffolding was first set up on the west side of the south façade beyond the sides of its porticoes. The pediment was cleaned from top to bottom, and then the columns and the ashlar were treated in the same manner.25

On 9 March 1969, Joe Petrak reported to the Superintendent that the exterior marble treatment was completed in June of 1967. The marble was scrubbed prior to waterproofing."26 Hydrozo

"Clear-Stone” was then applied on the entire masonry as a water repellent.27 Clear-Stone

23 Petrak, 23.

24 Batchelor, 1-2.

25 National Park Service, INHP Archives, Photograph Collection, Unaccessioned, Second Bank of the United States, 17 August 1964, negative # 8613, photograph by W.A. McCullough.

26 Joseph Petrak to the Superintendent, Memorandum, 9 October 1969, Historic Architect Files, INHP.

27 Batchelor, 5-7.

contains 2 1⁄4% silicone solids as produced by the General Electric

Co., Silicones Division.28 In March

1974, Harold Heller mentioned that in the 1960's a siliconate was applied to the Second Bank "which today [1974] remains quite clean.

On close examination of this building, it was found that surfaces exposed to the weather are not

[any longer] protected but areas such as the protected surfaces of the columns still repel water."29

Traces of this water repellent still exist (See Section 8.0).

Figure 7: South portico in process of being cleaned. 1964.

In the early 1970's, the Second Bank was rehabilitated to become the National Portrait Gallery. A museum quality HVAC system and other new internal systems were installed. Marble cleaning and repairs were carried out on both the interior and the exterior of the building during this period.

Revised specifications mentioned that new marble should have a tooled weathered surface or a rubbed sanded surface to match existing stone. New marble was used for both Dutchman repairs and new construction. Some windowsills might have been repaired in this fashion, however most appear to have been tooled with a point chisel. The Dutchman repairs were to be epoxied tightly into place in carefully cut out deteriorated sections. Specifications state what should have rather than what actually occurred.30 The Historical Architect’s office of Independence National Historic

Park has architectural drawings that indicate where new stone-blocks were placed in the early

1940's, early 1960's, and the early 1970's building campaigns.

28Penelope Batchelor, "1974-1976 Construction Phase Masonry Construction Methods Used," Appendix VI of "Historic Structure Report Historical and Architectural Data First Bank of the United States" (Philadelphia: n.p., 1981), 228, INHP.

29 Harold Heller, "An Approach to the Restoration and Preservation of the First Bank," Appendix V of "Historic Structure Report of the First Bank of the United States" (Philadelphia, n.p., 1981), 206-221, INHP. Recent SEM-EDS analysis has verified the presence of silicon-based coatings on the protected portico walls.

30 Denver Service Center, "Specifications Adaptive Restoration and Rehabilitation Second Bank of the United States" (Philadelphia: n.p., 1973), 4-9, Historic Building File, INHP.

Windowsills and other marble blocks that displayed damage too shallow for Dutchmen were repaired with cement mortar patches. Notes from the contract and construction negotiations describe how damaged exterior marble sills were to be built up back to their original profiles so that the water drained away. The repair material was to be Weld-crete from Larson Products

Corporation in Rockville, Maryland. It was used in a "fortified topping process, which allows feather edging”. One part 'Weld-crete to three parts water was specified, the Weld-crete used in place of water as an admix to the original cement mix. The final product was to match the original stone sills in color and texture. Any loose spalling layers of the stone were to be taken off before being patched.31 Today, there are remains of what appear to be concrete patches on the lowest south portico windows. Dense cement repairs there tend to trap any water that seeps through the protective surface, thus causing more spalling than otherwise might occur.

The interior polished marble in the main banking room was cleaned using two methods. With the first method, the marble cornice stone was cleaned with FINOLA Abrasive Scouring

Powder, made by Masury Columbia

Company, Melrose Park, Illinois 60160.

This method was mixed with water, and the marble was scrubbed with steel wool. The powder was ineffective on the marble columns and capitols, which were cleaned with Wyandotte

Detergent Powdered Abrasive Cleaner.

This powder was added to a five to one mix of water and Clorox (sodium perchlorate) until a paste was made.

The poultice was trowelled onto the stone, and allowed to remain on the surface for a minimum of 24 hours.

Later, the poultice was washed off with clean water and a bristle brush."32

Figure 8: Interior column capitol cleaned with a poultice.

1974.

31 Craig Morrison, Notes, Meeting with Mike Callaghan Marble Shop, Historic Architect’s Files, INHP.

32 Penelope Batchelor, Notes, 12 December 1973, Historic Architect’s Files, INHP.

A photograph taken on 2 May 1974, documented an original column capitol had been cleaned with a poultice.33(Fig. 8)

Some marble deterioration was carefully recorded during the 1970's. In April 1971, a worker was photographed painting an unidentified cleaner onto spray paint graffiti on the north façade.34 (Fig. 9) A color slide taken in September 1975 shows yellow patches on the N-2 column, indicating old epoxy repairs.35 In 1975, Penny Batchelor noticed that a "rather sizable” piece of marble was on the verge of spalling off from the column next to the west of the north façade [Column 1]. "The

Figure 9: Worker cleaning spray paint vandalism. 1971.

piece is below waist level facing northwest." She suggested that the piece could be secured "with an epoxy glue used for stone repairs" on the First Bank at the west doorframe.36 The epoxy used for the east façade for the

First Bank was 10% Epi-rez 510 made by Celanese Coatings, Inc. in Louisville, Kentucky. The solvent was methyl ethyl ketone, and the mixing standards were followed according to United

States Patent No. 3,795,533.37 It is not clear if this treatment was executed.

Records made during the 1980's and 1990’s document the deterioration of the marble, the location of some of the minor repairs, and the maintenance practices of the period. The building sustained damage from both vandalism and stone decay. One photograph taken in November

1983 shows that pigeon guano stained the marble as well as "Roost-NO-More” pigeon control.38

On 15 July 1985, Bill Brookover inspected scratched graffiti with "the words `George W. 1776’

33 National Park Service, INHP Archives, Photograph Collection, Unaccessioned, Second Bank of the United States, 2 May 1974, negative # 157.4315.32, photograph by Eisenman.

34 National Park Service, INHP Archives, Photograph Collection, Unaccessioned, Second Bank of the United States, April 1971, negative #10307A, photograph by W.A. McCullough.

35 Color Slide, September 1975, William Brookover's File, INHP.

36 Penelope Batchelor to Superintendent of INHP, Memorandum, 10 November 1975, Historic Architect’s File, INHP.

Note: Only dimensional loss is recorded on the described location on the 1999 condition assessment drawings.

Therefore, the repair was ether not made or failed.

37 Penelope Batchelor, "1974-1976 Construction Phase Masonry Conservation Methods Used," Appendix VI of "Historic Structure Report First Bank of the United States" (Philadelphia: n.p., 1981), 227, INHP.

38 William Brookover Photograph, 1986, William Brookover's File, INHP.

carved into a column" in the north portico, designated N-4 by the Naudé report. The graffiti was lightly scratched into the marble surface and could be easily removed using soft bristle brushes and water.39 Scratched graffiti is currently visible on several columns on the north and south façades. A few fragments of marble fall from the building every few years. On 7 October 1986, John Kornich found a piece of fallen marble on the west end of the north portico, probably from the cornice.40 On 28 April 1989, two pieces of marble were found at the south façade in the alley way and on the porch near the S-1 column.41

Only small-scale repairs were conducted in the 1980's and 1990’s. On 8 May 1986, a small fragment of marble was readhered with epoxy on column S-2, as designated by the Naudé

Report.42 (Fig. 10) The type of epoxy was not recorded. From 1983 to the present, several fragments of marble had fallen off and were epoxied back in place by a stonemason, without any documentation. During the same time period, a mason installed Dugan limestone patches with a polymer-bonding agent. To prepare a patch, the shallow areas of the damaged stone were cut away with a four-inch diamond blade to insure a good key.43

Recent maintenance procedures may be equally problematic to accurately document.

For example, the pigeon guano was "cleaned" with city water on the north and south portico paving. The dirty rinse water washed down the steps and over the west edge of the portico.

As a result, the guano was deposited on the stair risers, the west wall of the portico, and the terrace-paving wall.44 Today, dark deposits near the bottom of the north and south portico ashlar indicate that dirty water also splashed

39 William Brookover to General Foreman Ross Flanagan, Memorandu 38.

40 John Kornich, Report to Historic Architects, 7 October 1986, Bill Bro

41 Report to Historic Architects, 28 April 1989, Historic Architect’s File, 42 National Park Service, INHP Archives, Photograph Collection, Unac May 1986, photograph by William Brookover.

43 Stone Mason Frank Doyle, Conversation with Author, August 1995.

44 William Brookover to Ross Flanagan, Memorandum, 13 August 1986

Figure 10: South portico, column 2, marble epoxy repair. 1986.

m, 13 August 1986, Bill Brookover's File, INHP.

okover’s File, INHP

INHP.

cessioned, Second Bank of the United States, 8

, William Brookover's File, INHP.

against the portico walls and columns. Bird guano can introduce both phosphate and nitrate salts into the marble as well.45 Recently, calcium chloride was the preferred deicing salt for the steps and walkways of the Second Bank, thus introducing chlorides into the marble.46

More attention has been paid to the building recently. Bird netting was installed around the pediment during March 1994, which reduced pigeon access and guano.47 In November 1999, a piece of the cornice fell; and in response, bird netting was installed around the projecting cornice.

In December 1994, Virginia Naudé and Bill Brookover inspected the exterior marble over two days. She advised that immediate repairs should be confined to the traditional mortar or marble repairs until more complex treatments are thorougly tested."48

In conclusion, the Second Bank was built and repaired using traditional methods and materials during the early nineteenth century. There were three exterior cleaning and waterproofing campaigns performed on the building in the twentieth century. Around 1922 to 1923, the building was cleaned with soap and water and probably waterproofed with hot paraffin wax. The second cleaning and waterproofing treatment occurred in 1942 but without any mention of any of the compounds or the methods used. In 1964, the exterior marble was cleaned with aqueous fluoride solutions (possible P-56 Brick and Stone Cleaner) and waterproofed with a siliconate, Hydrozo

"Clearstone." Reports of marble deterioration preceded the 1923 and the 1964 treatments.

Minor mortar and epoxy repairs as well as Dutchmen were performed at intermittent times in the twentieth century, often after marble spalled. Not all of the repairs and patches were recorded. In

1996 as part of a long-range conservation program for the exterior masonry, the Architectural

Conservation Laboratory of the Unversity of Pennsylvania began a renewed program of stone analysis, treatment testing, and masonry conditions survey.

45 Erhard M. Winkler, 230.

46 William Brookover Commentary on Memorandum from District Ranger to Safety officer, 30 January 1992, William Brookover's File, INHP.

47 William Brookover, Conversation with Author, 30 August 1995.

48 Naudé, Virginia. “Survey of Exterior Marble, Second Bank of the United States, Philadelphia, PA.” 1994, 18-19.

5.0 Marble Decay: An Overview

In developing a conservation program for any masonry building, a variety of factors must be considered including the age and history of the building, the chemical composition and mechanical properties of the stone, the nature of its decay mechanisms, and the rate of deterioration relative to building location and environment.

Marble is a carbonate-based metamorphic rock which like most building stones, will undergo alteration and decay from a wide range of factors including pollution and freeze-thaw, salt, and thermal cycling. The mineralogical composition and grain structure of each type of marble will ultimately determine how vulnerable it is to decay from weathering. While all marbles are susceptible to chemical dissolution from acidic agents, the texture and fabric of the rock will dictate to a large degree its specific response to weathering. Degree of foliation, presence of secondary minerals such as micas, graphite and pyrite, and grain size and shape will all affect its durability. Mechanical damage, often indicated by cracking, will result by overloading the cohesive grain-to-grain strength of the marble.

The original stone of the Second Bank is of two varieties: a coarsely crystalline creamy white marble and a light blue banded or mottled marble. Both are interbedded with dark blue to black siliceous dolomite. The marble is weakly metamorphosed and contains abundant micaceous inclusions and the calcite is not strongly recrystallized. The marble is loosely textured, with a marked foliation (or planar) fabric forming a series of parallel planes that are weakly held together. The dominant mineral is light blue calcite grains ranging in size from 100-400 microns, angular to sub-rounded in shape and nearly of pure calcium carbonate. There are also small amounts of magnesium and iron.49

Mechanical damage can occur in several ways. Columns and other supports can crack by tensile, compression or shear forces while smaller architectural elements can fail from traffic or construction vibrations. Long-term stresses cause plastic deformation or creep. More dramatic damage can occur from blasting or seismic shock. Quarry blasting is often used to extract rock for construction. The explosion triggers a stress pulse that the rock can absorb and store. As the pulse pressure lessens, the internal stresses are released by stone fragmentation and microcracking. The resultant cracking and spalling provide moisture and salt entry causing greater damage.

49 Elaine S. McGee. “Marble Characteristics and Deterioration.” In Philadelphia Merchants’ Exchange Conservation Strategy. Environmental and Cultural Resources Research Monograph No. 1 (Washington, D.C.: National Park Service, 1992), 13.

Salt crystallization is considered potentially one of the most damaging mechanisms to stone buildings, especially when a building is in a climate prone to frequent wet-dry cycles. Salt crystallization begins when salts are dissolved in water and are transported through the pores of the stone. Salts can also be deposited on the surface from the atmosphere, evaporating groundwater, or contaminants such as bird guano, cleaning treatments, and deicing salts.

Precipitated surface salts, or efflorescence, cause less damage than those crystallizing within the pores of the stone. Such subflorescence can exert sufficient internal disruptive pressure to overcome the grain-to-grain cohesive strength of the stone matrix. The amount of damage depends on many factors: most notably the species and combination of salts, the microclimate, and the porosimetry of the stone. Moreover, the presence of salts promotes condensation and rising damp which escalates the entire process. Most marbles are fairly dense with porosities of one percent or less; however as the grains become detached from internal mechanical stresses, porosity can increase deterioration.

Acidic attack from dry and wet deposition or from inappropriate acidic cleaning will dissolve the calcite and dolomite matrix and form gypsum crusts. Secondary mineral inclusions such as pyrite can accelerate this decay by producing sulfuric acid, which can also convert the calcite to gypsum. The formation of gypsum distorts surface details and is more vulnerable to loss as it is

25 times more soluble than calcite and its expansive structure is weakly attached to the unaltered stone substrate. The presence of expansive clay secondary minerals can also swell and produce mechanical stresses in the stone when wet or erode away more easily than other less water-sensitive inclusions. Carbon dioxide in rainwater forms carbonic acid, which over time converts calcium carbonate to soluble calcium bicarbonate.

The weathering of crystalline marble is a complex interaction of several decay mechanisms and varies according to the particular structure and composition of the marble as well as its orientation in the building. The surface of the Pennsylvania Blue marble is vulnerable to surface weathering

(i.e. disaggregation) because its calcite structure is weakly metamorphosed with poorly interlocking grain boundaries, and it has a large percentage of inclusions.