December 19, 2013

Rev. Taylor Moore St. Peter’s Episcopal Church 113 South Ninth Street Oxford, MS 38655

RE: St. Peter’s Episcopal Church Architectural Assessment of Sanctuary Building

Dear Vestry and Members of St’ Peter’s:

Enclosed is the final report from Wiss, Janney, Elster Associates, Inc. regarding moisture problems in the sanctuary of St. Peter’s Episcopal Church. Styled as an “Exterior Masonry Investigation,” Steve Kelley also inspected masonry interiors, particularly in the crawlspace and in the belfry to reach conclusions about the sources of moisture intrusion and to recommend solutions.

We believe this report provides a first step toward the long-term management of those issues. You should find encouragement that Steve gives the building a “clean bill of health,” for the most part. The problems we observed and that he identified in his report are problems with which you are already familiar. We are confident we have identified the full extent of those problems and their underlying causes. Taking a Hippocratic approach to your building – “first, do no harm” – will serve us best, so our recommendation is that we think of this as “managing” rather than “correcting” the problems.

This document includes the following: • WJE’s final report, including illustrative figures and charts. • An initial budget estimate, revised from the one presented to the Vestry on December 9, to includes additional masonry restoration in the crawl space and in the belfry interior – re-pointing and re-parging. • A description of electro-osmosis systems and how they might work in this proposed application. Note that we stop short of recommending any electro-osmosis implementation.

As I discussed with the Vestry on December 9, I add to, elaborate on, and establish priority among Steve Kelley’s recommendations in the following ways: First, implement the relatively easy and immediately effective tactics: • Currently, the existing downspouts on the building’s north side drain onto splash-blocks at grade, and from there into the well-developed swale that drains to the east. These downspouts should flow directly into a hard-piped, below-grade, storm-water drainage system tied to existing drainage inlet structures. This pipe can be installed in the same trench as the French drain system (which is the next item). • Install a French drain system near, but not below the foundation bearing elevation on the north, east, and west walls of the building, including around the base of the belfry. This

Post Office Box 1569 • Oxford, Mississippi 38655 662.234.7444 • Fax 662.234.0008 www.howortharch.com

should drain water from immediately below grade and rising groundwater, to reduce the amount of water available to wick up into the wall systems. The French drain will include a perforated pipe, gravel fill, and filtering fabric to keep fine soils and sand out of the gravel and pipe. It can tie into the same site drainage structures as the hard drainage pipe, but the perforated pipe and hard pipe should be separate so as not to introduce free water from hard pipe into the perforated pipe. • (Note regarding the two items above: We have not identified a readily accessible drain inlet near the back of the church. The existing swale on the north side of the church drains to a concrete flume and from there onto the parking lot. This is shallow with very little fall, so the run to a sub-grade storm drain may be some distance away.) • Disuse and remove or abandon sprinkler systems on the building side of the French drain system. Reduce watering as much as possible to ensure that whatever surplus water is introduced into the area can be drained by the French drain system. • Remove organic mulch from around the building and replace it, if you like, with a different soil cover that does not retain moisture in the soil. The next tier of tactics will require more care and investment: • Replace the roof and reflash the castellated parapets at the base of the steeple. • Begin a program of repointing mortar as indicated in the report, with duration to be completed within five years. Proceed in the following sequence of priority: o Begin with the belfry exterior. Note: repointing the top of the belfry can share scaffolding and/or lift expense with the roof work, so their schedule should be coordinated. o Second priority is the north wall. o Third priority is the east and west walls. o Fourth priority is the interior of the belfry, and finally the interior of the basement crawl space. • As the repointing begins, provided you have developed confidence in your restoration masonry restoration contractor, I recommend experimenting with removal of Portland cement parging, first on a limited basis and only with aggressive enough tactics to preserve the original building fabric – particularly the bricks – beneath the parging. Proceed only as aggressively as feasible without damaging the underlying material.

While this report completes the scope of our current agreement, feel free to contact me for further assistance or advice or if you have any questions. Thank you for your confidence in Howorth & Associates Architects.

Sincerely yours,

Thomas S. Howorth, FAIA, President ST. PETER'S EPISCOPAL CHURCH Exterior Masonry Investigation

Oxford, Mississippi

Final Report December 13, 2013 WJE No. 2012.2232

Prepared for: Howorth & Associates Architects PO Box 1569 Oxford, Mississippi 38655

Prepared by: Wiss, Janney, Elstner Associates, Inc. 10 South LaSalle Street, Suite 2600 Chicago, Illinois 60603 312.372.0555 tel | 312.372.0873 fax ST. PETER'S EPISCOPAL CHURCH Exterior Masonry Investigation

Oxford, Mississippi

Stephen J. Kelley Principal

Final Report December 13, 2013 WJE No. 2012.2232

Prepared for: Howorth & Associates Architects PO Box 1569 Oxford, Mississippi 38655

Prepared by: Wiss, Janney, Elstner Associates, Inc. 10 South LaSalle Street, Suite 2600 Chicago, Illinois 60603 312.372.0555 tel | 312.372.0873 fax

TABLE OF CONTENTS

Introduction ...... 1 Building Description and Construction History ...... 1 References ...... 2 Methodology ...... 3 Visual inspection ...... 3 RILEM Tube testing ...... 6 Electrical Resistance Testing ...... 9 Laboratory Testing ...... 10 Petrographic Analysis of Brick ...... 10 Absorption Tests of Brick ...... 10 Original Mortar ...... 11 Parge and Mortar Studies ...... 13 Buttress Parge ...... 13 Under Parge ...... 14 Conclusions and Recommendations ...... 14 Appendix A

ST. PETER'S EPISCOPAL CHURCH Exterior Masonry Investigation

Oxford, Mississippi

INTRODUCTION In accordance with the request of Howorth & Associates Architects, Wiss, Janney, Elstner Associates, Inc. (WJE) has performed an investigation of water issues at and around the bell tower and exterior walls of the St. Peter’s Episcopal Church in Oxford, Mississippi. This investigation took place on August 28 and 29, 2013. Stephen J. Kelley, AIA, SE of WJE performed the investigation with Tom Howorth of Howorth Associates. Laboratory studies were performed by Laura Powers of WJE.

BUILDING DESCRIPTION AND CONSTRUCTION HISTORY St. Peter’s Episcopal Church is a clay brick masonry structure that is located at the southeast corner of Jackson Avenue and 9th Street. The main entry is through the west side of the bell tower at the northwest corner of the sanctuary. The sanctuary is a basilica plan that faces east. It has seven bays running east- west, with wood hammerbeam trusses defining each bay.

On the exterior, the bays are defined by brick buttresses that have been parged with cement. The brick near grade at all four sides is also parged with cement. The sanctuary has a steep roof that is gabled at the east and west and is roofed with asphalt shingles. The steeple above the bell tower is a wooden structure clad in painted pressed-metal panels.

A Parish house and Office addition is located south of the sanctuary. These additions were not a part of our investigation.

According to the National Register of Historic Places nomination form (Appendix A), St. Peter’s Episcopal Church in Oxford, Mississippi is one of the most important parish churches in the Diocese of Mississippi. Its style, Early English Gothic Revival, is unique in Mississippi. A number of prominent individuals have been connected with the development of St. Peter’s and the church is a living monument, significant in the architectural, historical and cultural heritages of Mississippi.

The Rev. Professor Frederick A.P. Barnard, originally a faculty member at the University of Mississippi and later its Chancellor, was the first resident clergyman. The church sanctuary was constructed during Barnard’s tenure. The plans have been attributed to Richard Upjohn, a New York-based architect who was influential in ecclesiastical design, particularly in the period 1860-1876, but it is more likely that the building is a copy of a plan developed by Upjohn.

The builder was William Turner and receipts for its construction mention the purchase of more than 370,000 bricks, and lime and sand for mortar. The church was completed in 1859 and the first services were held on Easter Sunday, April 8, 1860.

During the Civil War, Oxford was invaded by Union troops under Generals Grant and Sherman. In 1864, General Andrew Jackson Smith burned the buildings in the town square, including the county courthouse. St. Peter’s Episcopal Church survived the burning of the town, making it the oldest remaining religious structure in Oxford.

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At the end of the War, the congregation, like the entire south, was left destitute and unable to pay the debt on the church. The debt was paid in 1871, allowing the church to be consecrated in accordance with Canon law.

The tall spire was added circa 1893 as a gift from Mrs. Alexander Pegues (Figures 1 and 2).

Figure 1. Historic view of St Peter’s Episcopal Figure 2. Historic view of St Peter’s Episcopal Church from the west. The view is undated but Church from the west. The view is undated but after 1893. after 1893.

A brick parish house and office addition designed by Memphis architect Noland Van Powell was added to the south of, and connecting to, the west entrance of the church in 1956-1957. It replaced an earlier wood- framed rectory.

St. Peter’s was designated a National Historic Site in 1975.

References  A Compilation from the Diocesan Journals by Miss Frances H. Walthall  A Goodly Heritage by John Crews  A History of Saint Peter’s Episcopal Church in Oxford Mississippi, Centennial publication (1851- 1951)

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 Biographical Dictionary of American Architects (Deceased) by H. F. Withey and E. R. Withey, Hennessey & Ingalls, Inc.: Los Angeles (1970) republished 1996  National Register of Historic Places Inventory - Nomination form for St. Peter’s Episcopal Church dated July 24, 1975.  http://stpetersoxford.dioms.org/about/history.html

METHODOLOGY The following methodology was followed during the course of our investigation:  Visual inspection of the Sanctuary structure from grade; inside the bell tower; the exterior of the bell tower from a personnel lift; and from inside the crawlspace beneath the Sanctuary  RILEM tube testing to obtain an indication of the comparative measure of the brick permeance, as well as mortars and parge coats on the exterior of the Sanctuary and adjacent to the bell tower  Electrical resistance testing to determine areas of excessive water within the masonry  Laboratory testing of the brick, mortar and parge coat

VISUAL INSPECTION The following conditions were observed on the facades during our survey from grade:  Some of the brick is weathering on the outside surface (Figure 3).  Cracks on the brick faces do not proceed through the brick units but appear to be fabrication anomalies that have become pronounced due to weathering (Figure 4).  Mortar joints are in fair to poor condition with cracking at the interface between the brick and mortar. They appear to be in worse condition on the higher reaches of the wall.  The parge coats on the buttresses are in fair to poor condition (Figure 5).

Figure 3. Close up view of the bricks at the base Figure 4. Deep fissures (which look like cracks of the north wall. They are becoming worn and that originated from the handmade fabrication some of them have face spalls. process.

The following conditions were observed on the inside walls of the bell tower above the ceiling of the entryway:  The walls have been parge coated. The parge is grey in color, most likely Portland cement-based, and is peeling away from the walls (Figure 6).  The mortar joints are in poor condition (Figure 7).

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Figure 5. Parged buttresses on the north side. The Figure 6. Interior of the bell tower above entrance parge is in fair to poor condition and promotes ceiling. The interior walls have been parged with organic growth (seen as darkening). cement which is typically in poor condition.

The following conditions were observed on the exterior west wall of the bell tower from a personnel lift:  The bricks in some areas are noticeably weathered on their exterior faces (Figure 8).  The mortar joints in some areas are typically in poor condition (Figure 9).  The cement washes at horizontal planes of the upper reaches of the bell tower have become debonded from the substrate (Figures 10 and 11).  The flat roofing at the base of the steeple is in poor condition, with holes in the membrane and delamination at the parapets (Figure 12).  Some of the exposed wood around the louvers of the steeple are rotted and in poor condition.  The painted pressed metal panels that clad the steeple are in fair condition (Figure 13).

Figure 7. View of the poor condition of the mortar Figure 8. Worn bricks on the west facade of the in the bell tower. Its brownish orange color bell tower indicates that it is the original mortar.

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Figure 9. Poor condition of the mortar on the Figure 10. The cement wash at the water table of west facade of the bell tower. Note the organic the bell tower is in poor condition and does not growth growing beneath the tuckpointing mortar, adequately shed water. indicating high levels of moisture.

Figure 11. Poor condition of the cement, bricks Figure 12. There is a hole in the flat roofing and roofing at the top of one of the crenellations membrane. The flashings are also improperly of the bell tower done and otherwise are in poor condition.

Figure 13. View of the painted pressed metal Figure 14. View of joist ends and brick in panels of the steeple crawlspace

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The following conditions were observed in the crawlspace beneath the sanctuary:  The mortar is typically in extremely weathered condition and, based on its color, appears to be the original mortar (Figure 14).  The joist ends are typically coated with what appears to be a preservative such as creosote. This treatment was applied after the joists were in place (Figure 14).

RILEM TUBE TESTING The RILEM tube test is an absorption test that is a variation of a more comprehensive water permeance test defined by ASTM E 514-11 Standard Test Method for Water Penetration and Leakage Through Masonry. The RILEM tube test method device was developed by the Réunion Internationale des Laboratoires et Experts des Matériaux, Systèms de Construction et Ouvrages.

A RILEM tube is composed of a shaft and a bowl. The bowl is adhered to the surface being tested with a waterproof material. The shaft, located above the bowl, is filled with water and the waterhead caused by the height of the shaft (about 4 inches) approximates a wind driven rain (Figure 15). The amount of water that runs through the surface being tested over time gives an indication of the permeance of that material. As the surface tested is very small (about the size of a quarter), it is desirable to perform numerous tests. For our purposes Figure 15. View of a RILEM tube test. The stop watch function of we wanted to obtain an indication the iPhone was used to time each test. of a comparative rate of water permeance between the brick, mortar and parge coats.

The results of RILEM tube testing on five bricks on the north facade are presented in Graph A. This testing indicated a wide disparity of water permeance from brick to brick, which is not unusual or surprising given the nature of these pre-industrial bricks.

The results of RILEM tube testing on three mortars on the north facade are presented in Graph B. The testing indicated the mortar to be less permeable than the brick.

The results of RILEM tube testing on five areas of parge coating on the north facade are presented in Graph C. The testing indicated the parge coat to be, on average, less permeable than the brick and similar in permeability to the mortar.

A comparison of the average permeabilities of the brick, mortar and parge coat are presented in Graph D.

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Graph A

Graph B

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Graph C

Graph D

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ELECTRICAL RESISTANCE TESTING A measurement of the relative humidity (RH) in the exterior walls was obtained using electrical resistance. This testing is an adaptation of ASTM F2659-10 Standard Guide for Preliminary Evaluation of Comparative Moisture Condition of Concrete, Gypsum Cement, and Other Floor Slabs and Screeds using Nondestructive Electronic Moisture Meter.

Two contact points were inserted into the masonry wall at each measurement point. The contact points were inserted by drilling a 3/32-inch diameter hole to a depth of 1/2-inch and then gently pounding a nail into each drilled hole until it was embedded in the brick. The electrical conductivity between these two points was then measured using a Delmhorst Moisture Meter (Figures 16 and 17). Low resistivity indicated excessive amounts of moisture in the form of liquid water or water vapor.

Figure 16. Two areas of electrical resistance Figure 17. A location where nine electrical testing and the Delmhorst Moisture Meter resistance tests were performed

This testing proved to be a valuable qualitative, rather than quantitative, test. Measurements were either 15-35 on the reference scale (acceptable) or 100 on the reference scale (not acceptable). Measurements were taken in approximately 40 locations on the north facade, south facade, and the upper reaches of the west facade of the bell tower. It was found that reference scale measurements of 100 were present at areas that were parged, including the buttresses. The reference scale would drop into the 15-35 range at areas where the brick was not parge coated. The exception was on the south side, which had a reference scale measurement of 20 at the upper reaches of the buttresses.

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In addition, a reference scale of 100 was measured in the brick work of the bell tower crenellations and areas directly under the watertable where the mortar wash had become debonded.

LABORATORY TESTING Petrographic Analysis of Brick Five solid (no cores) fired clay bricks were removed for examination and testing. All removed bricks were taken from the interior walls in the crawlspace and were easily removed by hand. Two bricks contained cracks but were essentially intact. Three bricks had been broken during removal or in transit to the laboratory. Surface dimpling and other textural irregularities of the formed surface indicate that the bricks were handmade. The original measurements of the bricks were approximately 8-1/4 x 2-1/2 x 3-3/4 inches.

The brick compositions are similar, based on microscopic examination of freshly broken surfaces and immersion preparations of clay matrix, grit and grog. The bricks were made with clay mixed with iron oxides, small amounts of vitreous grog (over-burned brick fragments), and small amounts of quartz sand. The color of the brick body varies among the samples from bright reddish orange to pinkish red to dark purplish red (Figure 18). The color range appears to be related to the brick firing temperature/duration, but could also reflect differences in raw material sources for brick-making. Uneven firing was common for bricks made prior to about 1870. The fired clay matrix of the darker colored brick is very hard Figure 18. Fired clay matrix color is shown on freshly broken and exhibits vitreous luster. These cross sections of the damaged bricks characteristics generally indicate high firing temperature and/or long duration of firing. The reddish orange and pinkish red fired clay matrix is soft (pinkish red) to very soft (reddish orange) and exhibits dull earthy luster. These characteristics generally indicate low firing temperatures and/or short duration of firing. All the bricks exhibited similar pore structure. Most pores are less than 0.08 inch in diameter.

Some brick faces locally exhibited a high degree of water-penetration resistance as indicated by water beading up on portions of the surface.

Absorption Tests of Brick Initial rate of absorption and 24-hour absorption were determined for the two intact bricks (JTC 2 and JTC 4) in general accordance with the requirements of ASTM C67, Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile. The results are presented in Table 1.

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Table 1. Absorption and IRA Data Specimen 24-hour Cold Water IRA - Mass Gain Absorption (corrected to 30 inches2) 2 12.3 percent 67 4 14.3 percent 25

Initial rate of absorption (IRA) is defined as the number of grams of water absorbed in 1 minute over 30 square inches of brick bed area. IRA, or suction, affects the strength of the bond between bricks and mortar. IRA acceptable values range from 10 to 30 grams. Brick with IRA above 30 should be wetted before installation to prevent the brick from absorbing too much water from the mortar, thus reducing cement hydration and weakening bond. In general, low suction bricks (low IRA) require leaner mortar to provide good bond and high suction bricks (high IRA) require mortar with high water retention or wetting the bricks. However, wetting the bricks before laying them can contribute to efflorescence. Modern bricks tend to be denser than older bricks and have lower suction.

Brick absorption is defined as the ratio of the weight of water absorbed under specified conditions of immersion and time to the dry weight of the brick. Absorption is an indication of the brick-making process. Low absorption bricks are generally dense, strong, and exhibit semi-vitreous luster indicating the brick was well fired (higher temperature/longer duration). High absorption bricks are generally porous, weaker, and exhibit dull luster indicating that the brick was fired at lower temperature and/or shorter duration.

The two bricks that were tested exhibit similar moderately high absorption, which suggests that the bricks may be susceptible to rising damp. The large difference in IRA is indicative of differently fired bricks; heat distribution in brick kilns in the mid-1800s was typically non-uniform, resulting in some bricks being under-fired.

Original Mortar Four mortar samples were removed from the crawlspace beneath the sanctuary and were visually determined to be representative of the original mortar.

The first sample consisted of multiple rounded fragments of reddish beige mortar that contains bright white nodules 1/6 inch to 3/8 inch in diameter. The sample is shown in Figure 19. The edges of the mortar fragments are rounded and dusty. The mortar is fairly firm and generally well consolidated. The largest mortar fragment was approximately 2 inches across and 1/2 to 5/8 inch thick. The mortar is soft and fairly easily crushed. The white nodules, which consist of carbonated hydrated lime, are harder and frequently larger in size than the particles of softer reddish beige binder.

The mortar consists of fine aggregate natural siliceous sand dispersed in a fully carbonated hydrated lime binder that contains orange-red clay and small amounts of brick dust (Figure 20). Traces of Portland cement and natural cement were not observed. The fine aggregate consists of sub-rounded to sub-angular particles of quartz, feldspar, and minor chert. The fine aggregate appears to be fairly well graded to No. 30 sieve size. Total air content was estimated at 3 to 5 percent. The mortar appears to be slightly under- sanded by modern standards: aggregate content is 65.2 percent by weight. The natural color of fine aggregate removed from the mortar is light orange-red (Figure 21) due to the presence of adhered yellow clay and red iron oxide coatings on the particles.

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Figure 19. Sample 1 - Original mortar taken from Figure 20. Thin section micrograph of original basement. mortar Sample 1. Orange-brown patches are clay.

Figure 21. Appearance of the sand extracted from Figure 22. Sample 2 - Original mortar. White Sample 1. Red iron oxides fill surface depressions nodules are carbonated hydrated lime. Reddish on quartz particles. Millimeter scale. powder is mostly quartz sand with adhered iron oxide coatings.

Figure 23. Sample 3 - Original mortar taken from Figure 24. Sample 4 - Original mortar taken from basement basement

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The second sample (Figure 22), third sample (Figure 23), and fourth sample (Figure 24) are similar to the first. Sample 2 contained a 2 x 3 inch solid fragment that was 3/8 inch to 1/2 inch thick. Sample 3 contained multiple fragments of solid mortar, the largest approximately 1 x 1-1/2 inches. Sample 4 contained multiple fragments of solid mortar. The largest fragment was approximately 1-1/2 wide and 2- 1/2 inches long. All of the samples contained substantial amounts of reddish beige loose powder. The powder in sample 2 mainly consisted of quartz sand with an adhered coating of red clay and iron oxides. Loose powder in sample 3 and sample 4 consisted of quartz, sand, red clay, brick dust, and abundant fragments of white carbonated lime.

Parge and Mortar Studies The characteristics of the parge coat and the original mortars were assessed in accordance with the procedures described in ASTM C856 Standard Practice for Petrographic Examination of Hardened Concrete, which also applies to mortars.

Buttress Parge The samples removed from a buttress on the north facade consisted of multiple 1/8-inch thick fragments of hard, dense, mortar-like material (Figure 25). The largest fragments were approximately 2-inches in the longest dimension. The exterior surface was flat, dark beige-gray in color, and had a rough texture. The interior surface was frequently coated with a thin layer of lighter beige mortar-like material that is identical to the under parge sample described below. The exterior and interior surfaces are shown in Figure 26.

Figure 25. Location on a north wall buttress Figure 26. Contemporary parge sample. where the parge coat and undercoat were Fragments on the left show the rough exterior removed for laboratory analysis surface of the parge coat. The fragments on the right show beige mortar-like material adhered to the interior surface.

The parge coat consists of fine aggregate natural siliceous sand dispersed in an air-entrained Portland cement paste binder. The sand appears to be fairly well graded to No. 16 (standard sieve) maximum size and mainly consists of quartz. The paste is fully carbonated. Residual (unhydrated and mostly unhydrated) Portland cement particles are abundant, which is consistent with a low water-cement ratio mixture that was also probably stiff, as is typical for a parge coat application. Evidence of hydrated lime and/or fragment carbonate (masonry cement) was not observed. Total air content was estimated at 4 to 6 percent. Purposefully entrained air was not commonly used in Portland cement mortar until after about 1940, suggesting that the parge coat was applied within the last 70 years.

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No distress was observed in the parge coat. Although the paste is fully carbonated, no secondary deposits were observed in the air voids.

Under Parge The sample, removed from the same north buttress, consisted of multiple fragments of beige mortar-like material. The edges of the fragments are somewhat crumbly; however, the mortar is mostly firm and well consolidated. The parge coat side of most fragments is flat and exhibits dark gray discoloration. The largest fragment was approximately 2 x 3- inches and up to 1/2-inch thick. A few fragments had two parallel flat surfaces. No substrate material was attached to the surface opposite the parge coat. The sample is shown in Figure 27.

The mortar under the parge coat consists of fine aggregate natural Figure 27. Sample of beige mortar-like material underlying the siliceous sand dispersed in a fully parge coat carbonated hydrated lime, clay and brick dust binder. Portland cement particles were not observed. The binder contains frequent orange-red particles that appear to be clay and dark red particles that resemble brick dust; natural cement particles may be similar in appearance to brick dust but would exhibit evidence of hydration, which was not observed. The fine aggregate appears to be fairly well graded and mainly consists of quartz, feldspar and chert. Most of the sand particles are no larger than No. 30 sieve size (0.6 mm). Total air content was estimated at 2 to 3 percent. The mortar is not air entrained. No distress was observed in the mortar.

Conclusions and Recommendations The electrical resistance testing confirms that there is a definite issue with capillarity (rising damp) which is promoted by the parge coat at the base of the building and at the buttresses. The parge coat allows the moisture to rise higher in the wall because the parge restricts the vapor flow of the brick wall and limits the moisture in the wall to escape into the air. The RILEM tube and laboratory testing of bricks, mortar and parging bolsters this hypothesis.

In addition, the present Portland cement repointing mortar does not allow the wall to expire as much moisture as it did originally. Water held in the wall promotes the decay of the bricks and the original mortar. There are already signs of weathering of the brick which may have been accelerated by the Portland cement repointing mortar.

According to National Park Service Technical Brief 2: Repointing Mortar in Historic Masonry Buildings, “New mortar must have greater vapor permeability and be softer than the masonry units … [and] must be as vapor permeable and as soft or softer than the [original] mortar.” RILEM tube testing indicates that the

St. Peter's Episcopal Church Exterior Masonry Investigation December 13, 2013 Page 15 new mortar for repointing and parging is less vapor permeable than the brick. Laboratory analysis reveals that the original mortar was lime based and the new parging is Portland cement-based. Portland mortars are typically much harder than lime mortars.

The roof of the bell tower at the base of the steeple is in poor condition, as are the flashings at the crenellations and water table. These are also contributing to water infiltration. Electrical resistance testing confirms that the RH of the masonry wall is elevated directly below the roof and water table.

We recommend the following:  Repoint the entire building with lime-based mortars.  Further investigation, addressing the capillarity problems with one or more of the three options: o Install a more active subsoil drainage system around the building. o Remove the present parging and replace with a more appropriate parging that will allow the wall to breath. o Consider the installation of an electro-osmosis system that will address rising damp.  Install a new flat roof on the bell tower with proper flashings at crenellations and water table.  Repair mortar joints and parging on the inside of the bell tower above the Sanctuary entrance.  Repair mortar in exterior walls within the crawlspace below the Sanctuary.

APPENDIX A Form No. 10-300 (Rev. 10-74)

u l>i l c.u o I /\ l no L/E.r/\iv i ivic,i> i \jr i nc, 11^ i n,rs.n_/i\. KW&issisi 111 II Itill S&lll^Si NATIONAL PARK SERVICE • II 11 ill lltlllplllt NATIONAL REGISTER OF HISTORIC PLACES 1HIiIi lit 1111 INVENTORY -- NOMINATION FORM i

SEE INSTRUCTIONS IN HOW TO COMPLETE NATIONAL REGISTER FORMS TYPE ALL ENTRIES -- COMPLETE APPLICABLE SECTIONS II NAME

HISTORIC St. Peter's Episcopal Church AND/OR COMMON

LOCATION

STREET & NUMBER

113 South Ninth Street _NOT FOR PUBLICATION CITY. TOWN CONGRESSIONAL DISTRICT

Oxford ^m _ VICINITY OF First STATE CODE COUNTY CODE

M-i CCT QSTpp-f 28 Lafayette 071 QCLASSIFI CATION

CATEGORY OWNERSHIP STATUS PRESENT USE —DISTRICT —PUBLIC ^OCCUPIED —AGRICULTURE —MUSEUM X-BUILDING(S) X.PRIVATE —UNOCCUPIED —COMMERCIAL —PARK —STRUCTURE —BOTH —WORK IN PROGRESS —EDUCATIONAL —PRIVATE RESIDENCE _SITE PUBLIC ACQUISITION ACCESSIBLE —ENTERTAINMENT J?RELIGIOUS —OBJECT _IN PROCESS —YES: RESTRICTED —GOVERNMENT —SCIENTIFIC —BEING CONSIDERED X-YES: UNRESTRICTED —INDUSTRIAL —TRANSPORTATION —NO —MILITARY —OTHER: OWNER OF PROPERTY

NAME The Vestry, St. Peter's Episcopal Church STREET & NUMBER P. 0. Box 266 CITY, TOWN STATE Oxford __ VICINITY OF Mississippi HLOCATION OF LEGAL DESCRIPTION COURTHOUSE. Lafayette County Courthouse REGISTRY OF DEEDS, ETC. STREETS NUMBER Courthouse Square

CITY. TOWN Oxford Mississippi REPRESENTATION IN EXISTING SURVEYS

TITLE Historic American Buildings Survey DATE 1974 X-FEDERAL —STATE —COUNTY —LOCAL DEPOSITORY FOR Library of Congress, Division of Prints and Photographs SURVEY RECORDS CITY. TOWN Washington District of Columbia 1 DESCRIPTION

CONDITION CHECK ONE CHECK ONE

X.EXCELLENT —DETERIORATED _UNALTERED ^.ORIGINAL SITE —GOOD _RUINS 2LALTERED —MOVED DATE______—FAIR _ UNEXPOSED

DESCRIBE THE PRESENT AND ORIGINAL (IF KNOWN) PHYSICAL APPEARANCE

St. Peter f s Episcopal Church faces west on a prominent corner three blocks west of the courthouse square in Oxford, Mississippi. Typical of the later Gothic Re\r£val churches built in the Early English mode, St. Peter's closely resembles in^plan and detail the small Episcopal churches designed and influenced by Richard Upjofcn during the decade of the 1850s. The substantial brick structure consists of a siutple nave plan offset by a battlemented entrance tower placed laterally at the northwest corner. AjDripk parish hall and office addition to the south of the church edifice replaced, in 1£56^57, a frame rectory which the parish had erected in 1883 and converted to office uSe in 1949. Designed by Memphis architect Noland Van Powell, the St. Peter's parish hall annex connects with the church through a south doorway opposite the main church entrance. The three wings of the annex enclose a courtyard which leaves exposed the south wall of the original church exterior. Punctuated by lancet-arched windows between stuccoed buttresses, the restrained ex­ terior of the original St. Peter's relies almost entirely upon variations in the fine brickwork for ornamentation, a simple sawn vergeboard on the facade being the only applied decoration. Below the vergeboard, the facade fenestration consists of a single circular window centered above a pair of lancets flanked by buttresses. The arched facade windows, the large triplet chancel composition, and the lancet windows at the first and second levels of the tower are glazed with the original grisaille-patterned glass which was designed and manufactured for St. Peter's by Henry Sharp of New York in 1859-60. Completing the exterior of the church is a dormered octagonal spire which rises from within the battlemented parapet of the tower. Sheathed with tin stamped in a simplified fish pattern, the steeple may have been included in some form in the original plans for St. Peter's, but it was not actually added to the church structure until 18^3. Like the exterior, the interior of St. Peter's is characterized by restrained but finely executed features which are not diminished by extraneous ornamentation. The exposed construction of the arch-braced roof rises from impost blocks that terminate in simple acorn pendants, and between the hammer braces the plastered walls are in­ terrupted by lancet-arched window reveals which rise from a panelled dado. Not ar­ ticulated in the structural outline, the chancel is distinguished from the rest of the church interior only by its elevation one step above the choir, which in turn is raised three steps from the main floor level. The floors of these areas were raised in 1923-27 at the same time that an arch-panelled railing was installed to accommodate the pulpit and further delineate the choir and chancel from the rest of the church interior. Flanking the altar are ornamentally screened enclosures which were con­ structed to support the pipes for the organ when it was installed in 1961. None of the moveable furnishings in St. Peter's date from the troubled Civil War years to which the struggling parish was subjected soon after the church edifice was completed. A list of gifts and memorials which today make up the interior fittings of St. Peter's supports the theory that, in the interest of economy, inferior grade tem­ porary furnishings were probably acquired at the outset, to be replaced gradually with items more suited to the quality of the church building. After the church debt was eliminated in 1871, faithful parishioners evidently turned their attentions to equipping the newly-consecrated building with necessary and appropriate fittings

(continued) [1 SIGNIFICANCE

PERIOD AREAS OF SIGNIFICANCE -- CHECK AND JUSTIFY BELOW

—PREHISTORIC _ARCHEOLOGY-PREHISTORIC —COMMUNITY PLANNING —LANDSCAPE ARCHITECTURE X—RELIGION —1400-1499 —ARCHEOLOGY-HISTORIC —CONSERVATION —LAW —SCIENCE —1500-1599 —AGRICULTURE —ECONOMICS —LITERATURE —SCULPTURE —1600-1699 ^.ARCHITECTURE —^EDUCATION —MILITARY _SOCIAI7HUMANITARIAN —1700-1799 —ART —ENGINEERING —MUSIC —THEATER X_1800-1899 —COMMERCE —EXPLORATION/SETTLEMENT —PHILOSOPHY —TRANSPORTATION _1900- —COMMUNICATIONS —INDUSTRY —POLITICS/GOVERNMENT —OTHER (SPECIFY) —INVENTION

SPECIFIC DATES 1855-60 BUILDER/ARCHITECT j^ Dunlap & Co./Noland Van Powell STATEMENT OF SIGNIFICANCE St. Peter's Episcopal Church has, since its completion in 1860, been one of the most important parish churches in the Diocese of Mississippi. The structure itself is unique in Mississippi as a fine example of the Early English style of Gothic Revival church architecture popularized in this country by English born architect Richard Upjohn; and it is ecclesiastically important as both the oldest extant religious structure in Oxford and a once-designated "Cathedral Church" (later "Pro-Cathedral") in the Epis­ copal Diocese of Mississippi. A number of prominent individuals have been connected with the development of St. Peter's, and the church is today a living monument signifi­ cant in both the religious and architectural heritages of Mississippi. A collection of bills, receipts, and letters related to the construction of St. Peter's survives in the Mary Buie Museum in Oxford as an important resource in the study of the church structure, and the well-preserved records of the Diocese of Mississippi contain a great deal of data concerning the development of the Oxford parish. St. Peter's was from its conception a particularly important diocesan mission because of its proximity to the University of Mississippi, established at Oxford in 1848. The actual construction of the church marked the culmination of almost twenty years of Episcopal missionary work in the Oxford community, encouraged and supported by a growing contingent of potential parish members. The town of Oxford, county seat of Lafayette County, Mississippi, was incorporated in 1837, and the first Episcopal services held there were conducted by the Reverend Andrew Matthews of Hernando in 1840. Other clergy from nearby towns held periodic services in Oxford throughout the 1840s, but in 1848 the Right Reverend James Hervey Otey, provisional Bishop of Mississippi, indicated in his journal the influence which the new University of Mississippi was to have on the eventual establishment of a more organized Episcopal congregation and the subsequent construction of a substantial church building: Sunday, October 22 - At Oxford, Lafayette County, I read Morning Prayer in the Presbyterian Church, baptized three children and preached. This place being in the close neighborhood of the University of Mississippi, which has recently commenced operations, and to which the young from various parts of the State may be expected to resort, should receive immediate attention from the Church. An active and efficient missionary ought now to be on the ground sowing the precious seeds of God's truth. . .

In November, 1850, the Right Reverend William Mercer Green, newly ordained as the first Bishop of Mississippi, was able to report the definite beginnings of an Episcopal parish in Oxford, and his account of his visit there at that time is probably the first recorded mention of actual plans to build an Episcopal church structure in the town: EJMAJOR BIBLIOGRAPHICAL REFERENCES Dictionary of American Biography. New York: Charles Scribner's Sons, 1932. _A History of St. Peter's Episcopal Church, Commemor at ing Its One Hundredth Anniversary, Oxford, Mississippi: n.p., 1951. (continued) DGEOGRAPHICAL DATA o* ACREAGE OF NOMINATED PROPERTY leSS than One L. UTM REFERENCES All .6 I |2|6. 8|2i 2,5| |3 ,8iO f5|5. 0. 0| Bl . I I I , I . . , , 1 , , ZONE EASTING NORTHING ZONE EASTING NORTHING cl . I I I , I , , I I . I . I , , I D| . I I I . I I . 1 , 1 , I , , VERBAL BOUNDARY DESCRIPTION

LIST ALL STATES AND COUNTIES FOR PROPERTIES OVERLAPPING STATE OR COUNTY BOUNDARIES

STATE CODE COUNTY CODE

STATE CODE COUNTY CODE

FORM PREPARED BY NAME/TITLE Elizabeth P. Reynolds, Architectural Historian ORGANIZATION DATE Mississippi Department of Archives and History April, 1975 STREET & NUMBER TELEPHONE

P O KOY S71 (601) 354-6218 CITY OR TOWN STATE Jackson, Miss. 39205 STATE HISTORIC PRESERVATION OFFICER CERTIFICATION THE EVALUATED SIGNIFICANCE OF THIS PROPERTY WITHIN THE STATE IS: NATIONAL__ STATE X LOCAL___

As the designated State Historic Preservation Officer for the National Historic Preservation Act of 1966 (Public Law 89-665), I hereby nominate this property for inclusion in the National Register and certify that it has been evaluated according to the criteria and procedures set forth by the National Park Service.

FEDERAL REPRESENTATIVE SIGNATURE May 27, 1975 TITLE State Historic Preservation Officer DATE Form No. 10-300a (Rev. 10-74) UNITED STATES DEPARTMENT OF THE INTERIOR NATIONAL PARK SERVICE

NATIONAL REGISTER OF HISTORIC PLACES INVENTORY -- NOMINATION FORM

CONTIIMUATION SHEET______ITEM NUMBER PAGE ______

printed in New York. Published collections of his editorials from these two periodicals were widely circulated in England as well as the United States, and his numerous other writings were equally popular. Thompson came to Mississippi from Trinity Church, New Orleans, in 1882, when he was elected Bishop Coadjutor, and he was Bishop of the Diocese of Mississippi at the time of his death in Jackson in 1902. In addition to Dr. Barnard and Bishop Thompson, the list of prominent people with close connections to St. Peter's includes Dr. John Millington (1799-1868), Dr. Albert Bledsoe (1809-1877), Jacob Thompson (1810-1885), and Francis Asbury Shoup (1834-1896). Millington, a noted English engineer, author, and teacher who came to Oxford in 1848 to be the first professor of natural sciences at the new University of Mississippi, was one of the early organizers and the first senior warden of St. Peter's parish. Associated with Millington in the founding of St. Peter's, his fellow faculty member Dr. Bledsoe later served as assistant secretary of war in Jefferson Davis's cabinet and became famous in post-Civil War years as the unreconstructed founder and editor of the Southern Review. Prominent in the early political organization of north central Mississippi, Jacob Thompson, who served six terms in Congress (1839-1851) and was secretary of the interior under President Buchanan, became a confirmed member of St. Peter's in 1853 and later contributed liberally towards the construction of the church edifice. Distinguished as a brigadier general in the Confederate Army and later as an inspiring teacher and cleric, Francis Asbury Shoup was teaching applied mathematics at the University of Mississippi in 1868, when he, like Barnard before him, was ordained to the dioconate and began his church career as rector of St. Peter's Episcopal Church, Oxford. orm No 10-300a Rev. 10-74) UNITED STATES DEPARTMENT OF THE INTERIOR NATIONAL PARK SERVICE

NATIONAL REGISTER OF HISTORIC PLACES INVENTORY - NOMINATION FORM

CONTINUATION SHEET______ITEM NUMBER 8_____PAGE 3______

Frederick Augustus Porter Barnard is probably best known for his tenure (1864-89) as president of King's College, New York, during which time his efficient administration expanded the school into the present Columbia University, where Barnard College stands as a memorial to his many contributions. But St. Peter's church, which Barnard served as rector from 1856 to 1861 while he was successively president and chancellor of the University of Mississippi, also reaped the benefits of his dedication and administrative talents. In 1857 Dr. Barnard reported to the diocese that "sufficient means have been at length raised for the erection of a modest building, and a committee has been appointed on the part of the Vestry to enter into the contracts for the work. A suitable lot has been purchased near the Public Square." By deed dated November 19, 1855, the lot on which St. Peter's now stands was purchased by the Vestry from Philip A. and Mary D. Yancey for the sum of six hundred dollars. What became of the lot offered to the con­ gregation by Col. John D. Martin in 1850 is not known, but once the lot "near the Public Square" was acquired, arrangements for building a church proceeded under Barnard's leadership until the structure was completed, albeit without its steeple, in 1860. It is not known whether an architect was employed for the project or not, but in any case Dr. Barnard probably played an important part in the selection of a design for St. Peter's Although a parish tradition that Richard Upjohn himself furnished the plans for the church has not been substantiated, it is likely that the planners of the Oxford church were familiar with Upiohn's Rural Architecture, published by G. P. Putnam in 1852, and/or with some actual examples of UpJohn's work in other parts of the country, as many features of St. Peter's church resemble elements repeatedly employed by Upjohn in his designs for small Episcopal churches. Left vacant of regular clergy during the Civil War, St. Peter's was not eligible for official consecration until 1871, at which time Bishop Green pointed out that "through the generous contribution of a few friends, . . . the debt has been extinguished and the building made free to be set apart for God's service." By 1883 a rectory had been completed adjacent to and south of the church building, and by the following year, evidently because Bishop Coadjutor Hugh Miller Thompson resided in Oxford, Bishop Green was referring to St. Peter's as a "Cathedral Church" of the diocese. At Bishop Green's death in 1887, Thompson was elected the second Bishop of the Diocese of Mississippi, and the designation of St. Peter's as "Cathedral", or "Pro-Cathedral," continued at least until 1889, when Rev. John A. Harris was referred to in diocesan records as the "rector of St. Peter's Church" rather than the"dean of St. Peter's Cathedral" as had been customary during the previous five years. Bishop Thompson (1830-1902) was an important church figure whose close association with St. Peter's lends the Oxford church significance beyond its temporary role as Mississippi's first cathedral. A native of Ireland, Thompson entered the Episcopal ministry in Nashotah, Wisconsin, in 1849. After a number of years as a missionary in Wisconsin, Thompson became rector of Christ Church, New York, where, according to the Dictionary of American Biography, the popular teacher, preacher, and scholar "attracted large congregations." From 1860 until 1871, Thompson edited the Chicago- based American Churchman, and subsequently he became editor of the Church Journal, jrm No. 10-300a lev. 10-74) UNITED STATES DEPARTMENT OF THE INTERIOR NATIONAL PARK SERVICE

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CONTINUATION SHEET______ITEM NUMBER 8 PAGE 2______In the village and neighborhood of Oxford, I found several individuals and families desirous of enjoying our services, and willing to do what they could towards procuring them. They even spoke of attempting to build a church, a liberal individual (Col. Jno. D. Martin) of Holly Springs having presented them a suitable lot for the purpose.

Bishop Green returned to Oxford the following May for the express purpose of holding an organizational meeting of the "friends and members of the church" he had encountered there, and in his comments on the meeting he joined his predecessor in attaching larger- than-local missionary importance to the new parish and its plans to construct a church:

. . . The meeting was opened by calling Prof. John Millington, L.L.D., to the chair. The congregation was then duly organized as "St. Peter's Church" and the Vestry and Wardens elected in Canonical form . . . Nor should I be regarded as showing my undue partiality to this undertaking, when I commend it, as I now do, to the special attention of every portion of the Diocese. At this place is the University of the State . . . There are now between one and two hundred students in the various Departments, and the number is increasing. Among them are to be found some of the sons of the Church ... To take due care of such, to preserve them from the temptations of a College life, and to keep them in the way in which they have been trained, is certainly the duty of that Church to which they look as to a nursing mother ... It is upon these grounds, that I now bespeak the favorable regards of the Diocese generally, in the attempt to erect a Church at that place ... If they should attempt soon to erect a Church, I trust that, for the reasons given above, every part of the Diocese will contribute something toward the undertaking.

In spite of the bishop's enthusiasm, however, the newly organized parish of St. Peter's for some time thereafter continued to attend only occasional services in various pro­ visional quarters. Their interest in their mission did not wane, however, and in 1855 the Reverend Thomas B. Lawson of Grenada introduced a figure important to the future progress of St. Peter's when he reported to the diocese that "from January last this parish has been generally under the charge of the Rev. Prof. Barnard, whose able administrations will make it grow rapidly. They are zealous and faithful in their endeavors to erect a church building, and will no doubt succeed." In a brief report submitted to the diocese in the same year, the Dr. Barnard whose "able administrations" Lawson had praised pointed out to Bishop Green the difficulties inherent in being served by a rector in Lawson's position, "residing at a distance and being encumbered with the care of the churches of Pontotoc and Okolona." As a result of this report the bishop visited Oxford in December of 1856, ordained Dr. Barnard to the ministry, and appointed him the first resident rector of St. Peter's church. orm No. 10-300a Rev. 10-74) UNITED STATES DEPARTMENT OF THE INTERIOR PORNPS USE ONLY NATIONAL PARK SERVICE liCEMlD.^-^-^- NATIONAL REGISTER OF HISTORIC PLACES INVENTORY -- NOMINATION FORM

COIMTIIMU ATION SHEET______ITEM NUMBER 7. PAGE2 ____

such as the baptismal font (1873), altar cross and vases (1874), altar rail (ca. 1881), lectern (1884), altar (ca. 1887), hymn board (1892), and processional cross (1915). The extant bills, receipts, and letters pertaining to the labor and materials employed in building St. Peter's reveal much about the craftsmanship and supply sources which contributed to the physical appearance of the church structure. In a "Measurement of the Brick Work on the Episcopal Church at Oxford," a Captain E. C. Boynton calculated that, at twenty bricks per cubic foot of wall, a total of 370,120 bricks would be needed to construct St. Peter's. Accordingly, the records show that $1,850.60 was paid to J. F. Dunlap & Co. (also called Dunlap & Worley) of Oxford for "Laying 370.120 Ms. of Brick as per Capt. Boynton's measurement at $5.00 per M. , Furnishing Lime Sand and Labor [and] Hauling Brick." On December 23, 1859, a Mr. J. D. Grace of Oxford received a "note for Four Hundred Dollars on Contract for building Episcopal Church in Oxford, Miss.," but whether Grace was connected with Dunlap or acting in­ dependently is unclear. At least three separate payments totalling $1,000 were made to a William Turner (also referred to as W. Turner & Co.), however, "on contract for building Episcopal Church," so it seems likely that more than one builder was involved with the project. M. J. McGuire, who in 1852 was advertising in the Oxford Democratic Flag as an architect and civil engineer, was apparently engaged in the building supply business by the time St. Peter's was constructed, as the available records indicate that he was paid in 1860 and 1861 only for "materials furnished by him on the Episcopal Church," and not for any design services rendered. In November, 1859, St. Peter's was billed by Stratton, McDavitt & Co. of Memphis for 25 barrels of lime and 2 barrels of plaster of paris, and by May 3, 1860, M. Dove of Oxford had re­ ceived $178.38 in payment "for plastering the Episcopal Church." As agents for the Western Foundry in Memphis, Stratton, McDavitt & Co. also supplied St. Peter's with the 18 cast iron "Oval Ventilators" which are still in position at regular intervals in the stuccoed foundation of the church. Completing the documented details of the church construction, the itemized bill of G. W. Strickland, who advertised as a "House, Sign, and Ornamental painter" in Oxford newspapers during the 1850s, guarantees "5 cote work and graind oke," suggesting that the pine woodwork in St. Peter's, including the original "264 yards of seats," was initially painted in a faux bois manner rather than stained as it is today. : orm No. 10-300a Rev. 10-74) UNITED STATES DEPARTMENT OF THE INTERIOR NATIONAL PARK SERVICE

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CONTINUATION SHEET 2______ITEM NUMBER 9t PAGE 2______

McCrady, Edward. "St. Peter's Episcopal Church Organized in Year 1853," Oxford (Miss.) Eagle, December 16, 1937.

Oxford, Mississippi. Mary Buie Museum. Kate Skipwith Collection. Scrapbook and collected papers related to St. Peter's Episcopal Church.

Stanton, Phoebe B. The Gothic Revival and American Church Architecture, 1840-56. Baltimore: Johns Hopkins Press, 1968.

Upjohn, Everard M. Richard Upjohn, Architect and Churchman. New York: Da Capo, 1969.

Upjohn, Richard. Upjohn's Rural Architecture. New York: G. P. Putnam, 1852. On microfilm at the Mississippi Department of Archives and History. St. Peter's Episcopal Church December 19, 2013 Moisture Abatement Improvements Howorth & Associates Architects Budget Estimate

Repointing of Exterior Masonry Gable End Walls 1,068 sf @ $15 psf = $16,020 North Wall 524 sf @ 15 psf = $7,860 South Wall 362 sf @ 15 psf = $5,430 Bell Tower 1450 sf @ 15 psf = $21,750 Equipment Allowance 1 al @ $10,000 ea = $10,000 Subtotal of Repointing $61,060

Reroof & Reflash Castellated Roof @ Bell Tower 1 al @ 10000 ea = $10,000 $10,000

Linear French Drains - Tie to Existing Drains North Wall 100 lf @ 60 psf = $6,000 East Wall 50 lf @ 60 psf = $3,000 West Wall 50 lf @ $60 ea = $3,000 $12,000

Interior Work on Bell Tower above Ceiling Repointing 960 sf @ $15 psf = $14,400 Parging 960 sf @ $5 psf = $4,800 $19,200

Interior Work in Crawlspace Repointing 1000 sf @ $7 psf = $7,000 $7,000

General Conditions Allowance $12,000

Allow for Parging Removal & Replacement - Test Panel or more $4,000

Electro-Osmosis Waterproofing Treatment - Not included in estimate $0

Contingency & Fees (15% of subtotal) $18,789

Estimated Project Cost $144,049 Electroosmotic Pulse Technology for Groundwater Intrusion Control in Concrete Structures

M. K. McInerney* and V. F. Hock U. S. Army Construction Engineering Research Laboratories Champaign IL 61826-9005

Abstract

Groundwater intrusion into a building can cause serious damage to mechanical equipment; can increase maintenance requirements, and can make affected areas uninhabitable or even unusable. Electroosmotic pulse (EOP) technology offers an alternative to conventional water control techniques. Not only can it mitigate some water-related problems from the interior of affected areas without excavation, but it can further mitigate corrosion damage to mechanical equipment along with humidity and mold problems. EOP technology is based on the concept of electroosmosis; the movement of an electrically charged liquid under the influence of an external electric field. A system has been developed to apply electroosmosis within concrete structures by applying a pulsating electric field. During fiscal years 1994 and 1996, EOP technology was demonstrated at two Army sites. In both cases, the location of the groundwater intrusion was through the floor and walls of poured concrete basements. This paper presents the results of the experimental evaluation of system performance at McAlester AAP. The most conclusive data from this field test is the output power of the EOP power supply. Power data clearly indicates the beneficial effect of the EOP system on the moisture content of the concrete.

1. INTRODUCTION

Groundwater intrusion through a building’s foundation can cause serious damage. In addition to increased concrete deterioration and accelerated rebar corrosion, basement dampness can ruin expensive electrical and mechanical equipment, which is often located in basement space; can increase maintenance requirements through frequent repainting or cleaning to combat mold growth; and can make affected areas uninhabitable or even unusable due to poor air quality.

In selective problem areas, the usual approach to the treatment of water intrusion problems is to ‘trench and drain’, in other words, to excavate and expose the wall area and the base of the foundation, to replace waterproofing on the wall surface, and to install a drain tile system around the building or affected area. Other areas, such as floors, are untreatable using conventional methods.

Electroosmotic pulse (EOP) technology offers an alternative that can mitigate some water-related problems from the interior of affected areas without the cost of excavation. Further, by lessening water seepage through concrete walls and floors, indoor humidity is reduced, thereby alleviating corrosion damage to mechanical equipment, lessening mold problems, and enhancing indoor air quality.

In 1809, F.F. Reuss originally described electroosmosis in an experiment that showed that water could be forced to flow through a clay-water system when an external electric field was applied to the soil. Research since then has shown that flow is initiated by the movement of cations (positively charged ions) present in the pore fluid of clay, or similar porous medium such as concrete; and the water surrounding the cations moves with them. The basic physics and chemistry of electroosmosis can be found in several textbooks and treatises (e.g. Glasstone, 1946 and Tikhomolova, 1993).

A system has been developed to apply electroosmosis commercially to concrete structures by applying a pulsating electric field. It is called electroosmotic pulse (EOP). The pulse sequence consists of a pulse of positive voltage (as seen from the dry side of the concrete), a pulse of negative voltage, and a period of rest when no voltage is applied. The positive voltage pulse has the longest interval and the negative pulse has the shortest interval. As a result of this, the pore fluid moves (on the average) in one direction. The amplitude of the signal is typically between 20 and 40 Volts DC (VDC). The positive electrical pulse causes cations (e.g., Ca++) and associated water molecules to move from the dry side towards the wet side, against the direction of flow induced by the hydraulic gradient, thus preventing water penetration through the below-grade concrete structure. One of the most critical aspects of this technology is the negative voltage pulse. This allows control of the amount of moisture within the concrete which prevents overdrying of the concrete matrix and subsequent degradation.

An EOP system is realized by inserting anodes (positive electrodes) into the concrete wall or floor on the inside of the structure and by placing cathodes (negative electrodes) in the soil directly outside the structure. The density of the anode and cathode placement is determined from an initial resistivity test of the concrete and soil. The objective is to achieve a certain current density and thus create an electric field strength in the concrete sufficient to overcome the force exerted on the water molecules by the hydraulic gradient. Figure 1 illustrates the EOP process.

Currently, the reasons for the increased performance of the EOP system over standard DC electroosmosis for drying concrete are not well understood. However, it is speculated that the change in polarity results in the reversal of some of the chemical reactions occurring during electrolysis. It is also believed that the rest phase (no applied voltage) allows the system to equilibrate. As a result of these effects, undesirable side effects such as acid production and increased corrosion are avoided. Also, use of a pulse sequence might prevent the concrete from becoming too dry.

+Volts (t) - -Volts Cathode - Copper Ground + - Rod Embedded in Soil 1 to Pulsed DC Power Supply 2 m from Basement Wall

Anode - ⊕ Mortared into Basement Wall And/Or Floor

Water

Cations ⊕

Inside Surface of Concrete

Concrete Soil

Figure 1. Cross section of concrete and soil showing the EOP process.

2. TECHNOLOGY DEMONSTRATION

During fiscal years 1994 and 1996, EOP technology was demonstrated at two Army sites; the mechanical room of a guest barracks at Fort Jackson, South Carolina and an office and storage area in the basement of the Health Clinic at McAlester AAP, Oklahoma. In both cases, the location of the groundwater intrusion was through the floor and walls of poured concrete basements. These demonstrations were performed under a technology demonstration program, and therefore a large research and development effort was not possible. Monitoring of system performance was performed in the field, as best as possible. Supporting laboratory work was not available nor was it possible. These demonstrations, and the EOP technology, are described in detail in Hock et al. (1998). This paper discusses the experimental measurements taken at McAlester AAP. The EOP system was installed in the basement of the Health Clinic (Building 5) at McAlester AAP during July 1996. At that time the basement had standing water in several areas; water seepage from cracking in the wall; efflorescence and high indoor relative humidity. Analysis of water infiltration revealed that only about half the basement was leaking, therefore the EOP system was installed only in the areas of infiltration. Rubber-graphite anodes were installed 13 cm above the floor and 28 cm on center. The total number of anodes used was 95. Four copper-clad steel ground rods (cathodes), 2.44 m long, were driven into the soil in the crawl spaces adjacent to the concrete wall in selected areas. Large cracks were repaired by filling with epoxy or nonshrink grout. Figure 2 shows the arrangement of the EOP installation.

To assess the effectiveness and evaluate the limitations of EOP technology several system and environmental parameters were monitored. The corrosion potential of rebar was measured using a 33-cm long piece of 1.27-cm steel rebar which was grouted into the wall along with a Ag/AgCl reference half cell. The half cell was installed so as to be behind the rebar, and separated from it by about 5 cm of concrete. (Three additional 15-cm segments of 1.27-cm diameter rebar were placed in other basement walls to provide different EOP conditions from which to measure the corrosion potential of the rebar.) The humidity inside the concrete wall was sampled using a dual humidity/temperature probe which was sealed in a small cavity in the wall. Since the cavity is sealed, the temperature and humidity of the cavity should be proportional to the temperature and moisture content of the concrete. Ambient room humidity and temperature sensors monitored the Environmental Health Office. The level of the water table directly outside the basement was also monitored. In addition to these sensors and probes, the electrical power consumption of the EOP Control Unit and power supply was tracked. The locations of these sensors are indicated in Figure 1. All these monitoring devices, except the rebar corrosion potential were fed into a datalogger that was installed on site and was remotely accessible via modem. The data was collected and stored in the datalogger until uploaded to a computer. The rebar to half-cell potential measurement could not be properly interfaced to the datalogger because of ground reference problems. The daily rainfall, average outdoor temperature, and average outdoor relative humidity at nearby McAlester airport were obtained from the Oklahoma Climatological Survey. Data was downloaded monthly from their INTERNET site.

Figure 2. Location of EOP system components and environmental monitoring sensors in Health Clinic basement. (1 ft = 0.3048 m, 1 in. = 2.54 cm) 3. DATA PRESENTATION AND DISCUSSION

The most significant data from the McAlester field test is presented in figures 3 and 4. These figures show the output power of the EOP system and the daily rainfall for a one year period. In addition to calculating energy costs, output power can be used to qualitatively evaluate the moisture content of the concrete. Because the system driving voltage is constant, the power output is directly proportional to the moisture content of the concrete. (Power is directly proportional to current; current is inversely proportional to resistance; and resistance is inversely proportional to moisture content.) A drop in power therefore indicates that the concrete is drying out, i.e. the resistance is increasing. Conversely, a rise in power indicates moisture absorption by the concrete. This effect can be seen in the data for May through August 1997, where the power increases following large rainfalls, and then decreases as the system drives the water out. The most likely explanation for the few inconsistencies in power versus rainfall can be explained by the location of the rain gauge, which is located about 8 km from the base at McAlester airport. Because thunderstorms in the plains are localized events, the rainfall at McAlester AAP can differ from that at the airport.

Water table data indicated that intrusion was not caused by a high water table. (At the Fort Jackson demonstration site, basement flooding occurred yearly because of the very high water table, often rising 1.5 m above the level of the mechanical room floor.) The water table never rose nearer than 0.65 meters below the basement floor, confirming that the water intrusion problem at McAlester was due to the saturation of the surrounding soil following rainstorms, as reported by the building’s occupants. Occupants also reported that the heavy rainfall at the end of May 1997 was a rainfall that normally would have “flooded” the basement, however the water was held back by the EOP system.

Results of the other experiments were inconclusive:

(1) Indoor absolute humidity was found to correspond directly with outdoor absolute humidity, as is shown in figure 5. (Relative humidity was converted to absolute humidity in order to eliminate temperature dependence.)

(2) Cavity humidity did not vary directly with power as was expected. Figures 6 and 7 show the absolute humidity (i.e., temperature dependence removed) of the wall cavity. Cavity temperature data indicates a strong correlation with room temperature and the sudden drop in absolute humidity in March corresponds to the end of the heating season.

(3) Results of the rebar corrosion potential experiments were inconclusive. There is evidence that the Ag/AgCl half cell is not compatible with the concrete and might be drifting from its reference potential. Measurements were also taken using a Cu/CuSO4 reference half cell, not only at the long rebar segment but also at the other three shorter segments, two of which were placed in non-EOP system walls. Measurement results were inconsistent, due possibly to the noise of the measurement technique, +/- 200 mV.

4. CONCLUSION

The most conclusive data from the McAlester AAP field test of an EOP system is the output power of the EOP power supply. Because the moisture content of the concrete is inversely related to its resistance, a decrease in power indicates that the concrete is drying out, while an increase in power indicates moisture absorption by the concrete. This is confirmed by comparing power and rainfall data where power is seen to increase following large rainfalls, and then decrease as the system drives the water out again. This correspondence also supports the assumption that the water intrusion problem at McAlester was due entirely to periodic saturation of the nearby soil, as reported by the building’s occupants who stated that, prior to installation of the EOP system, the water came in following rain storms.

This field test concludes that the application of EOP technology for control of groundwater intrusion in below- grade concrete structures is a desirable alternative to conventional trenching and tiling: the EOP system installed in the 50 8.0

45 7.0 40 DC Power 6.0 35 30 5.0 25 4.0 20

3.0 Rainfall (cm)

DC Power (Watts) 15 2.0 10 Rainfall 5 1.0 0 0.0 November December January February March April Month

Figure 3. EOP Control Unit output power and local rainfall for November 1996 through April 1997.

25 8.0

7.0 20 6.0

15 5.0 Rainfall 4.0

10 3.0 Rainfall (cm)

DC Power (Watts) DC Power 2.0 5 1.0

0 0.0 May June July August September October Month

Figure 4. EOP Control Unit output power and local rainfall for May through October 1997.

50 0.020 45 40 DC Power 0.015 35 30 25 0.010 Indoor 20 Absolute Humidity DC Power (Watts) 15 0.005 10 5 Outdoor 0 0.000 November December January February March April Month

Figure 5. EOP Control Unit output power and indoor and outdoor absolute humidity for November 1996 through April 1997. 50 0.020 45 40 0.015 35 Wall Cavity Humidity 30 25 0.010 20 Absolute Humidity DC Power (Watts) 15 0.005 10 5 DC Power 0 0.000 November December January February March April Month

Figure 6. EOP Control Unit output power and absolute humidity of the wall cavity for November 1996 through April 1997.

50 0.020 45 Wall Cavity Humidity 40 0.015 35 30 25 0.010 20

DC Power (Watts) 15 0.005 Absolute Humidity 10

5 DC Power 0 0.000 May June July August September October Month

Figure 7. EOP Control Unit output power and absolute humidity of the wall cavity for May through October 1997.

basement of Building 5, McAlester AAP, Oklahoma successfully prevented water seepage; the cost of installation was 40 percent lower than the cost of the conventional trench and drain approach; the operating cost of the EOP system is negligible, less than to the expenditure of burning a 25W light bulb, and; a cost/benefit analysis using Payback-Upon-Price- Comparison and Payback-Over-Time show a very favorable payoff of the EOP technology over conventional technologies.

REFERENCES

Glasstone, S., Textbook of Physical Chemistry, 2d ed., D. Van Nostrand Company, Inc., Princeton, NJ, 1946.

Tikhomolova, K.P., Electro-Osmosis, Ellis Horwood Limited, Chichester, West Sussex, England, 1993.

Hock, V.F., McInerney, M.K. and Kirstein, E., Demonstration of Electro-Osmotic Pulse Technology for Groundwater Intrusion Control in Concrete Structures , CECER-FL-94-8, Construction Engineering Research Laboratories, Champaign, IL, April, 1998.