B08_Att_4_Sargent_Johnson_Veranda_Tile_Mural_Assessment.pdf

Sargent Johnson Veranda Tile Mural Conservation Assessment and Treatment Recommendations

Prepared for

Todd Bloch, RA

Historical Architect/Preservation Manager

San Francisco Maritime National Historic Park by

Katharine Untch, MA, CAS, Conservation Strategies

Art, Architecture, Archaeology www.CultureConservation.com

December 7, 2023

San Francisco Maritime Sargent Johnson Veranda Tile Mural National Historic Park Conservation Assessment and Treatment Recommendations

Conservation Strategies www.CultureConservation.com Art Architecture Archaeology December 7, 2023 Page 1 of 27

Table of Contents

I. Introduction

II. Project Team

III. Methodology

IV. Background

A. About the Artist

B. Methods of Mural Construction

C. History of Treatments

V. Conditions

A. Loose or separating from wall

B. Spalls

C. Cracks

A. Missing Grout

B. Losses

C. Surface Discoloration

D. Worn Glazes

E. Discolored Grout

F. Foreign Residues

VI. Recommended Treatment

A. Cleaning

1. General

2. Foreign Residues

3. Discolored Grout

4. Surface Discoloration

B. Loose tiles

C. Spalls

D. Cracks

E. Losses

F. Missing Grout

G. Cosmetic Touchups

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I. Introduction

The glazed ceramic tile mural, “Sea Forms”,1 created by the artist Sargent Johnson in 1939 as part of the Federal Art Projects program, adorns the north elevation of the veranda of the San Francisco Maritime Museum, located at 900 Beach Street, San Francisco, California.

Sargent Johnson glazed tile mural along the north wall of the veranda (looking east). Katharine Untch for NPS, November 28, 2023.

The mural shows conditions needing remediation, most notably some of the tiles are separating from the wall, glaze spalling, cracks, surface dirt and debris. This report outlines existing conditions by typologies and makes general recommendations for treatment to aide the National Parks Service in securing a qualified bidder to conduct the repairs.

1 Aquatic Park Bathhouse (Maritime Museum): Johnson Mural ‐ San Francisco CA ‐ Living New Deal at https://livingnewdeal.org/sites/aquatic‐park‐bathhouse‐maritime‐museum‐johnson‐mural‐san‐francisco‐ca/

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II. Project Team

Client Representative

Todd Bloch, RA Historical Architect Preservation Manager San Francisco Maritime NHP 2 Marina Boulevard Building E, Fort Mason Center San Francisco, CA 94123

Contractor

Katharine Untch Conservation Strategies Art Architecture Archaeology www.CultureConservation.com

III. Methodology

The conservator and architect met on site to review condition concerns and discuss possible causes and preferences for treatments. The mural was examined only from the ground. Soundings (light tapping) was conducted to determine some of the loose tiles that were accessible. Full quantifications for conditions will be possible after the entire mural can be accessed by scaffolding.

Treatment recommendations are outlined, along with some options for materials based on the site location and mural conditions. It is assumed that through the bidding and contracting process, treatment substitutions will be considered and reviewed as needed.

Treatments are to comply with o The American Institute for Conservation Code of Ethics and Guidelines for Practice, and o The Secretary of the Interior's Standards for the Treatment of Historic Properties.

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IV. Background

The Maritime Museum is in the historic Aquatic Park Bathhouse Building “that was built in 1939 as a joint project of the City of San Francisco and the New Deal Works Progress Administration (WPA), and is the focal point of the Aquatic Park Historic Landmark District. This unique structure was designed in the Streamline Moderne style, a late offshoot of the Art Deco period, and mimics the clean lines of an ocean liner.”2

The Maritime Museum is in the Aquatic Park Bathhouse building. NPS Photo at Maritime Museum (in the Aquatic Park Bathhouse Building) ‐ San Francisco Maritime National Historical Park (U.S. National Park Service) (nps.gov), https://www.nps.gov/safr/learn/historyculture/bathhousebuilding.htm.

2 NPS website, Maritime Museum (in the Aquatic Park Bathhouse Building) ‐ San Francisco Maritime National Historical Park (U.S.

National Park Service) (nps.gov), https://www.nps.gov/safr/learn/historyculture/bathhousebuilding.htm.

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A. About the Artist

Sargent Johnson (1888 – 1967) was a “versatile American artist known especially for his paintings and sculptures of African American subjects”.3 Born in Boston Massachusetts, His father was of Swedish ancestry, and his mother was of African American and Cherokee ancestry. He attended Worcester Art School and arrived in San Francisco at the time of the 1915 Panama–Pacific International Exposition, and remained in the Bay Area. He attended the California School of Fine Arts (now the San Francisco Art Institute) from 1919 to 1923, where his teachers included the sculptors Beniamino Bufano and Ralph Stackpole.4 He also taught art classes at the Junior Workshop program of the San Francisco Housing Authority and at Mills College.5

Among his many artistic achievements and awards are a medal at the San Francisco Art Exhibition of 1925, and a three‐time winner of the Harmon Foundation medal for outstanding African American artist. In 1935 Johnson was employed in the massive Federal Arts Project in the Bay Area as an artist, senior sculptor, assistant supervisor, assistant State supervisor, and finally, unit supervisor.6

In addition to the glazed tile mural at the Aquatic Bathhouse, Johnson created the slate bas relief adorning the exterior south elevation along Beach Street.

B. Methods of Mural Construction

The mural is approximately 14’ high by 125’ wide,7 with additional elements adorning the walls in the two stairwells leading down to the first floor.

The mural can be accessed through the lobby visitor center and exhibits entrance along Beach Street, and exiting through to the veranda facing the San Francisco Bay. The Bathhouse building is constructed on a sloped embankment with a Beach Street level entrance on the south elevation and rear doors exiting the second floor veranda on the north. The mural covers the majority of the north veranda wall, as well as some surfaces down into two flanking stairwells to the first floor. There are five doors along the span of the mural. The two end doors are single standard sized doors and the three in the middle are glass double doors with glass transoms and sidelights.

3 Sargent Johnson | African American, Sculptor, Painter | Britannica at https://www.britannica.com/biography/Sargent‐Johnson 4 Sargent Claude Johnson ‐ Wikipedia at https://en.wikipedia.org/wiki/Sargent_Claude_Johnson.

5 Sargent Johnson ‐ Biography (askart.com) at https://www.askart.com/artist/Sargent_Claude_Johnson/89603/Sargent_Claude_Johnson.aspx.

6 Sargent Johnson ‐ Biography (askart.com) at https://www.askart.com/artist/Sargent_Claude_Johnson/89603/Sargent_Claude_Johnson.aspx.

7 Sargent Johnson Tile’s the Maritime Museum – Public Art and Architecture from Around the World (artandarchitecture‐sf.com) at https://artandarchitecture‐sf.com/sargent‐johnson‐tiles‐the‐maritime‐museum.html.

Sargent Johnson, image from Profile: Sargent Claude Johnson (1888‐ 1967) – Black Art Story at https://blackartstory.org /2020/09/01/profile‐ sargent‐claude‐johnson‐ 1888‐1967/

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For methods of wall construction to which the mural is attached, consult with the architect.

According to one source, Johnson stopped work on the mural, which is likely why there is an unfinished jagged edge of tiles near the east end.

When the project began, the building was to be a publicly‐accessible bathhouse. However, shortly after it opened, the City leased a majority of the building to a group of private businessmen who operated it as the Aquatic Park Casino, limiting the public’s use of the building. Because of this, Johnson walked away from the project before he had completed this interior tile mosaic.8

The “unfinished” portion of the mural is between the east single door and the first double door assembly where the stucco wall is painted green.

North wall viewed from east end. Doorway at east end with unfinished mural edge on right..

Three double doors with “unfinished” part of transome on the left. Middle and right double doors.

8 Public Art and Architecture from Around the World at https://artandarchitecture‐sf.com/sargent‐johnson‐tiles‐the‐maritime‐ museum.html.

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Right (west end) of mural over west stairwell.. West stairwell.

West stairwell. West stairwell.

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East stairwell.. East stairwell.

East stairwell.. East stairwell.

There are typically two general processes for constructing tile mosaics or murals; a direct or an indirect method. After laying out a design and pre‐cutting the tiles to shape, the direct method is to apply each tile directly into the wet mortar, in this case on the wall. The indirect method is to lay out the pre‐cut tiles face down and in reverse on a horizontal work surface with a design drawing on paper, and then lifting and applying whole sections to the wall. Once the mortar is set, the paper design drawing is removed from the face. Variations of either method may include a temporary rigid board support, a paper, cloth or mesh temporary facing, and/or permanent backing, such as a mesh, applied to assist in transferring the

Art Architecture Archaeology December 7, 2023 Page 9 of 27 segments to the wall. The mesh is sometimes left intact, embedded between the mortar and the back of the tiles.

The NPS architect provided an image of the mural during fabrication, with tile pieces laying face up horizontally on a work table in the west rotunda.

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Details in the image provide some indication as to the methods of fabrication. A cartoon or design is in the upper right corner. Cut‐to‐size paper patterns are evident in various sections of the tile layout. The tiles appear to have been hand cut and assembled face up within a temporary wood frame. Some hand tools are evident. The boxes of tiles are in the background, as is a bucket, and a quart size paint type can of some product. It is difficult from this image to tell how the tiles were eventually attached to the wall.

Some of the labels on the cardboard tile boxes, although very blurred in the image, may have Chinese characters on them. A few of the boxes have “Hermosa” labels. “Hermosa” was both a brand name and a location for tile manufacture, at one point owned by the American Encaustic Tiling Co. and acquired by Gladding McBean in 1933.9

From minimal surface observations at the corner that is separated near the east stairwell, no mesh is visible. A corner sample was removed showing stronger adhesion between the back of the tile and the mortar than the mortar and the wall. It is difficult to tell from the images and surface examination how the tiles were attached to the wall and whether there is any sub wall structure, or whether the tiles were attached directly into wet mortar. It is possible that a temporary facing and/or support was used to transfer sections of the mural from the west rotunda where tiles were assembled, to the wall.

Sample location.

The architectural art tiles themselves have a range of glazes and methods of manufacture. (The tile manufacturer(s) were not identified.) Tiles surrounding the doors, for example were cut or made to size, glazed, and then fired, as evidenced by the slight rounding of the glazed edges. The curved glaze edge tiles include those with metallic mirror glazes. Many of the colored tiles comprising the green to blue tones have cut edges without the soft curve of the fired glazed edges.

9 Historical Timeline of Franciscan Ceramics – Franciscan Ceramics Archive (gmcb.com) at https://gmcb.com/franciscan_archive/index.php/library/historical‐timeline‐of‐franciscan/ Also see Gladding, McBean ‐ Wikipedia at https://en.wikipedia.org/wiki/Gladding,_McBean, The tile detectives ‐ Los Angeles Times (latimes.com) at https://www.latimes.com/style/la‐hm‐tile14oct14‐story.html, and TILE MANUFACTURERS (caltiles.com) at http://caltiles.com/tile_manufacturers.htm.

Lower edge near east stairwell.

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The metallic glazed tiles have different underglazes such as white and cream to yellow colors. This may have been intentionally to show different metallic colors such as copper/bronze/brass vs. silver.

Detail of tiles with various colors, gloss, and Detail of door frame white return tile with rounded or flat cut glazed edges. metallic glaze tile rounded edges.

Each tile was cut to match very closely to the adjacent tiles and there are minimal (less than 1/16”) to no grout lines. In some areas the grout lines appear to have been painted a color to generally match the surrounding tile colors.

Detail of grout painted blue to match surrounding glazes.

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C. History of Treatments

There are no known previous treatments.

It is assumed that the mural may occasionally be cleaned by maintenance staff, probably with damp rags or rinsing with water.

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V. Conditions

Conditions are noted here by typology. Conditions are noted as inspected from the ground only. Further conditions may be noted and quantifications will need to occur after scaffolding is installed.

Conditions are listed by priority for stabilization, with cosmetic issues presented lower on the list. This does not necessarily presume order of treatment, however. As an example, while soils and drip marks are lower priority, all surfaces should be cleaned prior to stabilization.

A. Loose or separating from wall

Loose tiles were observed near the east stairwell. Soundings (light tapping) indicated separation extending approximately 1’ inward from the tile edge. The extent of blind tile separation from the wall is not yet fully known and will have to be further investigated once scaffolding is up.

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A sample of mortar was removed from the bottom edge and showed superior adhesion between the mortar and tile with separation between the mortar and wall.

Causes of the separation are not known, but contributing factors may include wall surface preparation, building wall movement from settling and/or seismic activity, fluctuations in temperature and relative humidity contributing to different rates of expansion and contraction between materials, or other unknown factors.

Adjacent to this area are drip marks down the painted wall below a window. Sources of water or moisture are unknown; however, there is a possibility of salt fog air condensing on the surfaces, perhaps on the window sill and dripping down? The water may also be from a previous window cleaning. This condition is included here in the event that moisture issues are contributing to tile separation from the wall.

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Above the irregular edge of the mural are some spots in the ceiling that may be cobwebs or indications of the presence of water. This will need to be further investigated when the ceiling can be accessed.

Area for further investigation.

B. Spalls

There are several areas of spalled, or actively spalling, glaze near tile edges. Contributors may be building movement or seismic, or salt fog air entering along the edges by capilary action and salt crystal formation during drying. The crystals take up more volume than when solubilized in water so may be pushing the glaze away from the cermaic substrate.

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Examples of numerous areas of glaze spalling.

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A similar type of glaze spalling is along the vertical edges of the door jams. Possible causes may include expansion and contraction of adjacent materials, different types of mortars or adhesives used around the door jams, and/or other contributing factors such as the solubilization and recrystallization of salt fog air.

One possible scenario may be that one edge of the tile is adhered to the door frame, while the remainder of the tile is adhered to the wall. Building movements, expansion and contraction, may be contributing to the tile cracks and spalls.

C. Cracks

There is a verticle crack extending through the middle of the two large door lintels. It is likely that these cracks extend into the supporting substrates behind the tiles, and may be related to lintel sagging or other building movement. The central door has a rectangular hole, probalby from a previous fixture. It may be possible to examine the interior of the wall from this access hole for futher investigations. Also note that the first double door assembly on the east end does not have tile mural over the lintel. If

Art Architecture Archaeology December 7, 2023 Page 18 of 27 needed, furher construction or structural investigations might occur at this location withou impacting on the mural.

Some tiles have cracks running through the tiles and/or glaze. Causes may include impact, thermal expansion and contraction, or building movement.

A. Missing Grout

Grout is missing in some areas.

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B. Losses

Two holes exist to the left of the single east door, likely from a previous sign or fixture.

There are a few minor glaze and ceramic tile chips.

An example of a small glaze and ceramic chip.

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C. Surface Discoloration

Some of the tile surfaces have discoloration that may be the result of surface salt efflorescence, or possibly sub‐surface efflorescence. The light green matte glazes seem to have this condition more than other glazed tiles, which might be expected since the matte glaze is likely more open pored than the high gloss glazes that can more easily shed water. Staining is also more evident around glossier glaze cut tile edges where water can enter more easily. Darker areas may also have combined soils, biological growth, or other residues or oxidation products (such as calcium suphates or gypsum combined with soot).

Examples of matte glaze discoloration.

Example of darker stained tile. Example of surface salt efflorescence in crizzled glaze.

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D. Worn Glazes

The most notable worn glazes are the metallic glazes.

Examples of worn metallic glaze, some with yellow underglaze and yellow metallic and some with white glaze and silver metallic surfaces.

Worn metallic glazes on fish.

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Another type of worn glaze is from use, wear or impact. For example, some of the tiles at the bottom of the east stairwell are damaged from impact with the metal gate.

Damaged glaze in east stairwell.

E. Discolored Grout

Grout lines are discolored, possibly from some biogrowth, dirt, grime, and/or accumulated foreign residues.

Examples of discolored grout.

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F. Foreign Residues

Foreign residues on the surfaces include paint, drip marks from unknown splashed on materials, tape residues, and chewing gum.

Paint spatters. Foreign material spatters.

Tape residues. Chewing gum.

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Drip marks. Drip marks.

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VI. Recommended Treatment

Treatment recommendations are based on a limited visual examination. No testing has occurred.

Substitutions for materials and methods can be submitted to the architect for review and approval prior to commencement of treatments.

A. Cleaning

1. General

Clean all mural surfaces with potable water applied with a pump sprayer or mister. Wipe with a soft sponge in a 1% solution of a non‐ionic surfactant. If necessary, clean with a soft brush, such as along grout lines. Work in sections to avoid surface drying. Before surfaces dry, rinse with a pump sprayer or mister. Hand wipe with soft rags and allow to air dry.

2. Foreign Residues

Pending test results, remove remaining foreign residues. For chewing gum try heat or ice and use mechanical tools to remove. For remaining gum and paint residues use a pH neutral non methylene chloride, low VOC paint stripper; or, as last resort, solvents in minimum quantities necessary.

3. Discolored Grout

Clean as described in “General Cleaning” with water or water and non‐ionic surfactant using a soft brush.

Rinse and dry. Do not use any additional chemicals or cleaners. Most grout discolorations are tolerable as the grout lines are very thin.

4. Surface Discoloration

Test clean in order of least harm with water and light melamine abrasive sponges, surfactant and water, baking soda poultice with water, baking soda light abrasion, and/or mild white vinegar solution, followed by ample rinsing and checking with pH test strips. Avoid using EDTA or other chemical products that might etch the surfaces. The goal is to test to see if some of the surface residues are removable without etching the glazes. Test results may show that it is better to just leave the discoloration than to remove it, especially if the discoloration is sub‐surface.

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B. Loose tiles

Two general methods for reattaching the loose tiles are removal and reattachment or grout/adhesive injection. The removal method may be unnecessary and higher risk of damaging tiles, such as cracking or tile breakage during removal. The alternative, injection grouts, also has risks of limited flow and the probability of having to introduce drilled holes to inject grout in blind areas that are not accessible along the separating outer edges of the mural.

For background on injection grouts, refer to the Getty Conservation Institute online resources on “Injection Grouts for the Conservation of Architectural Surfaces”.10

The contractor shall conduct tests on a handful of injection grouts to determine flow and adhesion. The injection grout should not be denser or harder than the ceramic tile and allow some flexural movement.

Review test results with Client. Following test results, mockup tile injections and determine extent of flow using soundings (tapping). Select method that provides tile adhesion with maximum injection flow to minimize number of injection ports.

Tiles that have fallen off or are removed can be reapplied using low compressive strength mortar and grout (less than 600 psi).

C. Spalls

Consolidate the spalled and spalling glazes with a ethyl methacrylate/methyl acrylate copolymer in ethanol. While a methyl methacrylate has a smaller carbon chain and may penetrate deeper, it has been known to yellow more, and the larger butyl chain polymers will penetrate less. The recommendation of ethanol is to reduce VOC odors while working on site. Most of the public will comprehend “alcohol” as less toxic than “acetone” smells. For deeper penetration, the areas can be pre‐wetted with ethanol prior to applying the consolidant.

D. Cracks

Clean cracks as much as possible using the general cleaning methods described above, including using a small brush, such as a soft toothbrush, to loosen and remove as much trapped dirt, soot, etc. as possible.

Do not widen or grind out cracks.

For very fine cracks (less than 1/32”), consolidate using the same method as “Spalls”.

For wider cracks, a flexible kitchen and bath type acrylic latex caulk may be used. The latex products should last about 10 years. Silicone sealants will likely last longer but have oils that may seep out and

10 Injection Grouts for the Conservation of Architectural Surfaces | Getty Projects at https://www.getty.edu/projects/injection‐ grouts‐conservation‐architectural‐surfaces‐research‐evaluation/.

Art Architecture Archaeology December 7, 2023 Page 27 of 27 cause staining. Modified polyurethanes may also be used as these will likely last longer, but may be more difficult to remove when retreatment becomes necessary.

If the sealant is “paintable”, surfaces may have paint added as described under “Cosmetic Touchups” below.

E. Losses

Minor chips and losses to ceramic tile can be filled with the same recommended grout (see under “Missing Grout”.

Glaze losses can be consolidated with the same acrylic resin copolymer used for the spalls (see under “Spalls”) and cosmetic touchups (see under “Cosmetic Touchups”).

The cut hole in the middle double door lintel can be covered with a plate fitted with spring clips. A caulk or sealant can be used. (See under “Cracks”.)

F. Missing Grout

Ideally the grout should be softer and more breathable and have more water vapor absorption/permeability than the ceramic tile fired clay body. Most grouts on the market today are cementitious and high strength, properties that may be contributing to edge glaze spalling.

The sizes and quantities for this project do not necessarily warrant the costs for ASTM materials testing of original materials. A Type O Mortar Mix (~350 psi) can be used for the grouts. This softer mortar may help reduce edge spalling of the tile glazes.

Provide a matching grout sample as a submittal for approval, followed by a mockup.

Clean out loose grout using a fine scraping tool such as a needle or scalpel. Wash and let dry to remove surface dust and debris. Replace missing grout with a custom or proprietary matching grout.

To match painted grout lines, see under “Cosmetic Touchups” below.

G. Cosmetic Touchups

For color compensation, use conservation grade acrylic paints or an exterior grade acrylic latex architectural paint.

Glaze transparency with color tinting is sometimes difficult to match and many synthetic dies do not hold colors as well as natural earth pigments. Pigments may be added to the clear acrylic resins, artists acrylic translucent paints may be used if color fast, and/or acrylic gels may be used to bulk up glaze chips or losses. Alternatively, clear acrylic resin solids can be applied with a tacking iron using silicon mylar. Touch ups may be less transparent than the glazes.

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tbloch Inserted Text E. Losses Minor chips and losses to ceramic tile can be filled with the same recommended grout (see under “Missing Grout”.

Glaze losses can be consolidated with the same acrylic resin copolymer used for the spalls (see under “Spalls”) and cosmetic touchups (see under “Cosmetic Touchups”).

The cut hole in the middle double door lintel can be covered with a plate fitted with spring clips. A caulk or sealant can be used. (See under “Cracks”.)

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