On-line Book
Book Cover to Mission 66 Visitor Centers. With image of Dinosaur NM Visitor Center, view from beneath ramp


Table of Contentss




Wright Brothers


Pertified Forest

Rocky Mountain

Cecil Doty



Appendix I

Appendix II

Appendix III

Appendix IV

Mission 66 Visitor Centers
Chapter 3
National Park Service Arrowhead


Building the Visitor Center

In mid-August 1959, the EODC was in midst of reviewing the plans, and bidding on the visitor center and cyclorama building opened September 29. The contract was awarded to the Orndorff Construction Company, Inc., of Camp Hill, Pennsylvania, for its bid of $687,349, an estimate $45,000 less than the second lowest proposal. [30] Total construction time for "one of the largest buildings in the way of Visitor Centers to date" was projected as a single year; it was Director Wirth's particular hope that the building could be dedicated while President Eisenhower remained in office. [31] The project's four primary contractors officially began work on November 18, though the electrical, cooling and heating, and metal workers awaited Orndorff's preparation. [32] Within a few days, the construction company had a tractor trailer at the site and inspectors checking elevation lines established by EODC Engineer Westerfield. According to the contract specifications for the visitor center, the rotunda was to be prepared for installation of the cyclorama painting within just one hundred and eighty days. To meet this tight deadline, the contractors were advised to give priority to the construction of the concrete drum. [33] After excavating a footprint 130 feet in diameter and digging spread footings, contractors began driving piles for the rotunda foundation. They were surprised to find that the rock did not meet required standards; in fact, it didn't appear to be the same material obtained by prior tests. Upon further investigation, the contractors discovered the building had been moved about twenty feet since the initial foundation inspection. During their December 17 site visit, the architects hired an expert to analyze the situation. Robert J. Stickel, a civil engineer from Camp Hill, Pennsylvania, suggested shifting the building an additional twenty feet to the east. [34] Throughout these inspections, the construction company insisted it could "do nothing until the center pivot point was established by the survey crew." [35] By January 1960, Neutra and Alexander had revised the foundation plan. Over the next month, the remaining footings were custom designed to suit their varying site conditions.

In early December, Neutra and Alexander congratulated the Orndorff Company for recognizing the "national importance" of the future building. [36] The architects had received the contract to supervise construction of their design, and it was in their best interest to anticipate mutual cooperation in the work ahead. [37] Over the next few years, both principals of the firm would visit the site many times and respond to everyday questions by mail and telephone. Dion Neutra remained based in Los Angeles, but represented the firm in official correspondence and on many site visits. [38] Weekly supervision of construction was undertaken by one of Richard Neutra's former assistants, Thaddeus Longstreth, who had since opened a private architectural practice in Princeton, New Jersey. As the firm's "eastern representative," Longstreth maintained a weekly record of construction progress, logging nearly one hundred supervisory reports between November 1959 and March 1962. He focused on "the interpretation of the plans and specifications from an architectural and aesthetic viewpoint rather than the mechanical aspects of the building." [39] Technical matters were the prerogative of subcontractors in California, including mechanical engineer Boris M. Lemos, electrical engineers Earl Holmberg and Associates, and the firm of Parker, Zehnder and Associates, consulting structural engineers. In addition, the project was under scrutiny by David O. Smith, the project supervisor. Although a Park Service employee, Smith acted as a liaison between the government and the architectural firm. The highest authority in the Park Service with intimate knowledge of the project was John B. Cabot, supervising architect of the EODC in Philadelphia, but even Cabot declared Gettysburg Superintendent James B. Myers the official "owner" or client. Along with these overseers, the crowd at the construction site included Willard Verbitsky, a 340-pound superintendent known as "Little Willie" by his co-workers at Orndorff Construction. Both John J. Bordner, vice president of Orndorff, and President Brickley S. Orndorff stopped by to check on progress and handled the project's substantial correspondence with its west coast designers. The construction company hosted an introductory dinner for the group on December 17, 1959, a few weeks after work had officially begun.

While the foundations were under scrutiny, the architects turned their attention to sample panels of the stone walls. Although the requirements for the stone masonry may have appeared stringent, the contractors had been forewarned by the building specifications, which stipulated every detail—from the three sample panels to the provision of a local example for the mason's examination. [40] The stone required in the specifications was native "'Arcure' Pennsylvania Sandstone in the tan, brown or buff color range." As the architects explained, the most aesthetically pleasing masonry pattern consisted of "darker and larger stones . . . nearer the bottom of the piers and color and size graduating toward the top to lighter and smaller pieces." [41] They also indicated that the sides of the piers as seen from the east were most important and that the very best stone should be reserved for the four piers nearest the entrance. [42] In preparing the sample, Longstreth and the contractors explored the surrounding area for historic examples of the desired "random rubble ashlar pattern with more irregular, triangular shapes." [43] The Vickery Stone Company of Upper Darby, Pennsylvania, dumped approximately 155 tons of Blue Mountain split-face Pennsylvania sandstone at the job site on February 25, 1960. The architects hoped to have the panel erected by December so that it could weather over the winter. [44]

Despite efforts to get off to a friendly start, the foundation problems inspired more doubts than confidence. When construction was still in its infancy, the architects warned Orndorff not to substitute less expensive or more accessible products for those specified in the contract. Neutra and Alexander insisted they could "not accept very much deviation for design reasons." [45] The firm's adamant adherence to specifications became a problem for the contractor because high-quality products were difficult to obtain; both parties disagreed on what they considered suitable substitutes for specified items, and such commitment to high standards resulted in countless delays. For example, the architects selected expensive Japanese tile distributed by a Los Angeles dealer to cover the inside of the cyclorama ramp. [46] This decision not only resulted in considerable delays, but evoked disapproval from those committed to the Buy American Act. The fact that the architects supervised construction undoubtedly helped the contractors understand the complex project, but it also allowed the design process to extend into the construction phase; the designers could not resist enhancing the building's aesthetics whenever possible. Rather than simply directing installation of the original tile, the firm continued to imagine new effects, envisioning "a mixture of two closely related shades of dark brown or black, perhaps alternating vertical strips to give a very subtle corduroy-like effect as a backdrop for the stainless tubes" and with a matte glaze to prevent any "glitter." [47] Regardless of additional time or expense, the architects based decisions on aesthetic issues and structural considerations that might effect the performance of the building. While such practice resulted in exceptional quality, the contractors and subcontractors were sometimes baffled by what they interpreted as capricious decisions.

When the spring building season began in early March 1960, the foundations were in place, and the architects focused their attention on concrete forms. Once the outer form work for the rotunda was finished, pouring began. The first pour was completed in sections between columns. The contractors worked their way around the circle, leaving space for the auditorium doors, and then moved on to the next vertical wall segment. Scaffolding was erected to hold workers and concrete in place as the layers of lifts accumulated. The rotunda's inner form was begun in August, and as construction progressed, it advanced in height along with the exterior. Photographs of the unfinished concrete shell in September show a fortress equally as impressive as the final product. The remaining wood scaffolding, with its tiny ladders still climbing up the side of the building in December, gives a sense of the incomplete rotunda's huge scale; in contrast, the finished form would ultimately succeed in dissolving into the grove, at least as much as could be expected from such a massive shape. The cylinder was of ribbed concrete, a decorative vertical pattern that required precise formation.

In the same way that Neutra and Alexander insisted on perfecting the rough and random look of the stone masonry, the architects were determined to achieve a "crisp and clean" contrast in the concrete. The aesthetics of both interior and exterior could suffer from shoddy form work, careless concrete preparation, or improper pouring. Although Park Service project supervisor David Smith warned against using prefabricated plywood panels, the contractors objected to the expensive 1- by 6-foot shiplap required in the specifications. [48] In a letter to Orndorff, Dion Neutra explained why seemingly insignificant details of the concrete process were aesthetically important and mentioned similar techniques used by other architects, such as the "Unesco Building in Paris and any recent work by Le Corbusier," to illustrate his point. [49] Such modernist buildings used concrete to create "pure" forms without any suggestion of their fabrication. The capacity of concrete to take on a smooth, sleek appearance in a variety of shapes was the very reason it became a featured material of modern architecture. The cyclorama ramps under construction might prove expensive and challenging to design properly, but they would also contribute to the building's streamlined aesthetics. Chamfer strips were removed from exposed corners because they made "the building look clumsy and warehousey rather than sharp and crisp." [50] According to Dion Neutra, such attention to detail was "why the Park Service went west for their architect, and why this will be a distinguished building with all of us working on it, dedicated to this proposition." [51] The firm finally compromised by allowing plywood forms in unexposed areas, such as the inside curved surface of the mechanical room and the portion of the rotunda hidden by the painting. Some covered areas, the outside surface of the central drum in particular, required shiplap to produce "a true curve." Although the firm anticipated a certain amount of rubbing out of form lines, they preferred to "have as little patching or rubbing as possible, but rely rather on the best form work to avoid problems." [52]

As Neutra and Alexander and contractors debated the importance of proper form preparation, they also confronted deficiencies in structural concrete. The concrete columns in the main rotunda, alphabetized from F to Z, each required proper footings and piers. Park Service supervisor David Smith reported on defective concrete in the main R column that extended from the foundation to the support of the cyclorama drum; Longstreth's construction report described the problem as "stone pockets" that compromised the density of material. [53] The architects immediately demanded the removal and replacement of the column. They were alarmed "to think that these results are being obtained on a building that will depend in such large measure on the quality of its concrete finish." [54] Later that month, the adjacent T and S columns were discovered to be equally faulty and also required removal. [55] Upon further inspection, it was determined that the "honey-combing and stone pockets" resulted from the failure to adequately vibrate the concrete. Soon after, Smith reported "errors" in the footings and asked for suggestions. Toward the end of April 1960, he agreed to make a surprise visit to the concrete mixing plant to take test samples of sand and aggregate. [56] In the meantime, Brickley Orndorff promised to write the company with his complaints. Flawed concrete preparation, usually a result of improper vibration, plagued contractors and architects alike for the duration of the project.

Despite the construction problems, "the Lincoln Memorial at Gettysburg" was included in a profile of the firm by Pacific Architect and Builder in May 1960. An aerial view of the building from the entrance facade, rendered in pastels or watercolor, showed the three reflecting pools darkened and the rotunda dwarfed by surrounding trees. The short description of the building noted that it was under construction "on the famed battlefield some 200 yards from where President Lincoln made his speech," and stood "only a stone's throw from the horrifying spot where the contest found its climax." The location of the building was clearly considered an admirable quality. [57]

The architects returned to the aesthetics of the stone masonry piers and walls in mid-April 1960, when a sub-contractor began work on a second sample panel. During construction Longstreth deemed the panel too similar to the initial rejected attempt. The frustrated mason described his previous success erecting stone walls for the National Park Service at Camp Green Top (Catoctin Mountain Park) in Thurmont, Maryland. Longstreth visited the park, only to find that the walls in question were "too polychrome in range with a preponderance of square shaped pieces." [58] After Cabot and Neutra inspected the work the next month, they accompanied contractors to an old barn on Route 116 west of Gettysburg. A corner of the structure exhibiting the desired variety of stones and mortar thickness became the example for visitor center masonry. [59] On June 21, Longstreth and Bordner traveled to the Blue Mountain Stone Quarry ten miles northwest of Harrisburg in search of stone that might cut into satisfactory shapes. They discovered two potentially useful types of stone—one with a "regular" effect when cut and the other likely to form "larger irregular shapes" but too gray in color. [60] The quarry owners were so sure of success that they volunteered to construct a product sample for the architects' approval. Longstreth and Smith then accompanied them to the exemplary barn to see the desired stone pattern. The next week, the quarry owners erected the sample from stone on the site supplemented with their own Blue Mountain stone. Longstreth reported that this panel "showed great improvement over previous efforts, having more irregular shapes, thinner dry-wall appearing joints, larger and darker stones at the base." [61] Nevertheless, he felt that the nature of the rock still hampered efforts and further construction would require constant supervision. He hoped that the principles learned while building the samples could be transferred to the field, allowing the masonry covering the sides of the rotunda's external concrete piers to become "fieldstone panels." The five piers nearest the main entrance extended beyond the edge of the rotunda and created a platform for the concrete cylinder.

Once the mason had actually erected part of pier R and column P, Longstreth commented on the lack of color variation; tones were supposed to graduate from dark on the bottom to lighter nearer the top. He also demanded thicker, darker stone for the panels, noting that the thinner stone might be reserved for the center of the walls. The stones were to appear naturally chunky and randomly selected, but the wall itself required proper alignment. In terms of pattern, Longstreth asked the mason to avoid "uphill joints" or stones laid too vertically. The mason was to begin with the least visible piers, such as the north side of pier Q, before moving on to the featured south facade. [62] During supervision of the pier work in early November, Longstreth warned the mason of "downhill joints," and suggested that he constantly stand back from his work to avoid such monotonous effects. Although larger and wider stones were now in use, the color range was still disappointingly small and the joints too horizontal. Given the range of colored stone provided and its varying appearance when split, Longstreth felt that only constant effort would achieve the desired results. [63] By this time, John Cabot had given Longstreth full authority over this aspect of the project. [64]

Stone panel and stone wall on the south
end of the office wing
Figure 35. Stone panel and stone wall on the south end of the office wing, 1962.
(Photo by Lawrence S. Williams, Inc.)

In the fall of 1960, as work began on the interior surfaces of the building, aesthetics took precedence once again. When Orndorff submitted vinyl wall covering for the office partitions, the architects were horrified by samples that "might do in a bar or club, but not in this type of structure." [65] They also disapproved of the wood sample panels, noting "the dust and pock marks, as well as the too-glossy finish," a result far different from the sought after "satin, even, low sheen, full bodied, rubbed effect." As for the colored concrete required in the exterior ramp, the architects preferred the chocolate color supplemented with abrasive additives for additional texture. Orndorff sent three samples sealed differently but all including sidewalk grain chips, and not very tactfully indicated that the architects had now received "the full range of the colors as manufactured by A. C. Horn." [66] The next week, the architects reported the lack of any attempt to use silicon carbide (alundum grains) to create the specified textured surface. [67] To complicate matters, the exterior ramp required extensive structural revisions. While the architects complained about the contractor's interior selections and form work, the Park Service blamed the architects for a five-month delay in submitting a finish schedule. [68] Even as they exchanged complaints, however, all parties pressed on. Orndorff scheduled terrazzo work in December, beginning with the ground floor lobby and restrooms, continuing to the second floor office wing and then entering the cyclorama. [69]

Gettysburg Visitor Center and Cyclorama, view of the roof structure under construction.
Figure 36. Gettysburg Visitor Center and Cyclorama, view of the roof structure under construction, December 1960.
(Courtesy National Park Service Technical Information Center, Denver Service Center.)

During the slow and difficult interior design phase, work on the cyclorama roof proceeded quickly and relatively harmoniously. In a September 1960 report to the architects, Parker, Zehnder and Associates explained details of the construction joints for the cyclorama beam, wall, and floor. The appearance of the concrete forms changed significantly in October, when contractors began to erect steel girders and beams for the rotunda roof. Two cranes were required, one to place the cyclorama roof steel and another to lift the concrete for the interior columns. Project Supervisor Smith updated the architects on conditions at the site and described his view of future progress:

As it stands now, the center post is solidly supported 2' above the final elevation and 6 girders from J clockwise . . . inclusive are attached. After the cyclorama wall is completed, the other four beams and purlins will be erected and the cables connected. I assume at this time the blocking will be removed (although I see no provision such as wedges to do this) letting the center post settle to its final elevation. I assume this is the correct point in the installation for the welding of the beams to the center post. [70]

Neutra visited the site around Christmastime specifically to photograph the interesting spiderweb pattern created by the rotunda's exposed steel framing and endured "great pains and great physical discomfort" in the process. [71] According to Smith, the revealed roof structure had already attracted much attention. The Bethlehem Steel Company took pictures of the cyclorama drum and roof structure for a full-page advertisement and brochure publicizing its bridge cables. The rotunda roof was built around an 18-foot center column suspended with steel purlins radiating outward above a system of "prestretched and proofloaded bethanized bridge strand." [72] The bridge cables were attached to the base of the central column and to the upper perimeter of the cylinder, forming a flexible "web" of fibers. After the erection of the steel but before installation of the gypsum roof, the cables were adjusted to vertically align the central column. The framework of purlins and girders above resembled a wagon wheel. One of the photographs in Neutra's Buildings and Projects shows two men near the central "trunk" dwarfed by the steel umbrella overhead. Views were also taken from above the cyclorama, probably from one of the cranes used in the construction process. It was a dramatic photo opportunity and one that would soon disappear under layers of lath and plaster. By the following summer, the roof scuppers had already become filled with leaves, and Smith planned a regular inspection schedule to keep the drains clear. [73]

The firm's specifications emphasized their quest for "Architectural Effect," a subjective standard they strove to achieve through materials, methods, and even decorative art. Bush-hammered columns formed an important part of the original interior scheme, and as the project progressed, this rough appearance became increasingly desirable. While contemplating the color scheme, the architects decided to leave all bush-hammered columns in their natural state to expose the black aggregate and reduce the quantity of dark brown. [74] After the bush-hammering process, columns required additional work to "remove the spiral form marks and to give surface variation as called for in specifications." [75] In February 1961 all parties agreed that bush-hammered columns should be left natural on both the interior and the exterior. And by the next month, the preference for bush hammering included the bench surrounding the museum exhibits. The Park Service issued a change order to reveal the aggregate in the circular museum bench, "upon consideration of the color scheme for the building, and after seeing the effective result of the exposed aggregate in bush-hammered surfaces at various locations in the building." [76] The architects also improved the transition from the second floor corridor to the cyclorama ramp by substituting stainless steel for galvanized iron in the bridge spanning the exhibit area. Since the ramp was enclosed within a stainless steel cage of the same material and style as the rostrum, this choice unified the metal work in the museum. The transition plate was actually thin strips of steel with enough space between to create a dizzying effect when looking down at the terrazzo floor below. The plate and corresponding balustrade also provided support for a glass mural.

Just as they imagined the "floating" office wing, the architects conceived of a dramatic interior with office partitions "shooting on into the corridor and the feeling of the long vista of the windows continuing beyond." [77] Demountable partitions of the "flush movable type" produced by the Neslo Manufacturing Company in New York separated the office space in the second floor administrative wing. This system allowed removal of any panel in any order without affecting other partition walls. The individual laminated vinyl panels could be taken apart and rebuilt if necessary.

View looking south into the second floor 
lobby space
Figure 37. View looking south into the second floor lobby space, with offices beyond. The ramp up to the battlefield overlook is visible outside, 1962.
(Photo by Lawrence S. Williams, Inc.)

By mid-summer, architects and contractors prepared for work on the building's unusual solar window shade system. The entire east office window wall was covered by exterior louvers, which created a pattern of vertical lines that changed in width as the shades were manually cranked open or closed. The louvers were fabricated of ALCOA aluminum covered with a Lemlar primer and two coats of baked enamel finish. As Dion Neutra explained to the EODC, his father was "recognized as perhaps the originator of this type of solar control, having first used it some twenty years ago, when every piece had to be custom made." In 1956, the firm's Northwestern Mutual Fire Insurance Office (1951) was included in a book about innovations in aluminum construction. [78] This building is dominated by vertical aluminum louvers that extend from the 7-foot office windows beyond the spandrel below, producing a unified front facade. As Neutra reported, the architects had used the same design in more recent local projects with excellent results. He may have been thinking of the Amalgamated Clothing Workers Building (1956) near Wiltshire Boulevard or current work on the Los Angeles County Hall of Records, which featured "base-to-cornice light controlling, energy-conserving louvers" constructed about the same time as the visitor center. [79] In addition to the streamlined vertical lines of the louver pieces, the architects appreciated their transparency, which gave a contrasting sense of lightness to the surrounding concrete.

During construction, the architects decided to change from the manual louver controls to the Lemlar Manufacturing Company's system of automatic solar adjustments. The park hesitated to spend the extra money necessary for this luxury, but the architects were persuasive. According to Neutra, there were practical reasons for mechanizing the louvers. People tended not to adjust them until they were very uncomfortable and, once closed, they would usually remain shut since artificial lighting was provided. This "greater dependence on automation and push-button living" increased as the world modernized. Dion Neutra sent the park a letter from the manufacturing company stating that the cost of operating the louvers automatically would be less than the expense of hiring someone to turn the hand crank throughout the day. Lemlar suggested that curious park administrators inquire about the louvers at a milk company in Camden, New Jersey, where they had been installed in 1957. [80] After some delay due to travel engagements, John Cabot resolved the situation by explaining the Park Service's hesitancy to install "mechanical gadgetry." Nevertheless, Cabot was willing to approve the louvers, if provided with a hand crank for emergencies and the chance to review additional costs. The company's promise to install the mechanism itself sealed the deal. [81 ] The Lemlar Manufacturing Company sent their sun louvers to the site April 27, 1961.

The cyclorama's motorized doors could become an equally dynamic aspect of the main entrance facade, but they were only intended for use on special occasions. A portion of the east rotunda was outfitted with mechanical sliding doors, and a wall of the auditorium operated on a pivot. When both doors were opened, the museum became a speaker's platform and the south lawn an expansive seating area. The architects chose the Ferguson Door Company of Los Angeles to manufacture the motorized sliding and swing doors. After reviewing the Ferguson Company's installation and drawings, the architects were pleased with the workmanship of a complicated, technical project. They looked forward to the "spectacle" of watching "the doors all operating at once." [82] The next spring, project supervisor Smith reported that the "pattern sheets" for the Ferguson doors were undergoing a final adonizing test. The architects advised waiting to install the door panels until after all sandblasting, Thoroseal application, and plastering had been completed. [83] Finally, in early August, only a delay in the arrival of the doors prevented the Park Service from hanging the painting." [84]

If the louvers and walls only operated at certain times, the building's water features provided a constant source of stimulation. A few months earlier, the concrete had been poured for the upper pool on the office wing roof. This stretch of water extended the full length of the viewing deck before flowing down to an intermediary pool on the auditorium roof and cascading to a ground level pool near the visitor center entrance. The water was kept in motion by a "piped circulation system." According to the specifications, after the completion of concrete work, a "waterfall diverter" was required in the intermediate pool to "reduce splash, impact, and noise to a minimum, as audited from the Projection Room." [85] Pouring the concrete for the pools was a relatively straightforward process, but waterproofing them proved more challenging. By June 1961, a special polysulphide caulking compound was required in the pool joints to prevent water from leaking into the office wing below. [86] A few months later, the park "noticed that the concrete slab, placed over the roofing to provide a surface for the view deck, had moved thereby sheering the deck drains, pulling the cove base away from its backing and presumably rupturing the waterproofing." Besides the pool repairs, the adjacent view deck required a quarry-tile walking surface. [87]

Cyclorama building with auditorium doors
Figure 38. When the glass doors were opened, this section of the Cyclorama building's drum served as a stage complete with rostrum. The auditorium doors opened to provide indoor seating, and the lawn accommodated additional spectators.
(Courtesy Architectural Archives, University of Pennsylvania, Philadelphia.)

As the building neared completion, the consistency, size, shape, and pattern of stones in the rock walls continued to be a priority. Longstreth warned the mason to vary the top of the piers with larger, more horizontal stones. In a letter to Smith, he mentioned that larger, darker stones should appear at the bottom and suggested looking for proper stone at the top of the quarry. Superintendent Myers worried about the "dry-wall effect . . . which would cause excessive moisture entering joints." This problem could be avoided by packing the mortar more deeply and inspecting all areas while taking care not to create the "appearance of a tooled joint." [88] The work accomplished through the spring of 1961 was accompanied by an incessant aesthetic critique. In March, stonework was delayed while sub-contractors searched for additional dark-colored stone. The "triangular chinks" in pier T were removed and repaired. And the mason was reminded to "avoid repetitious shapes side by side." When the darker stone arrived at the site, supervisors complained about the thickness of the pieces. The joints were too wide and the stones at the bottom too small. By May 3, the south stone was eighty-five percent complete. In finishing up this important section, the mason was warned against creating a "quoining effect," in other words, suggesting a regular termination of the wall at the corner by using similar square stones. Finally in the fall of 1961, issues involving the stonework no longer related to the actual stones, but to the color of mortar joints and the painted ends of concrete piers. [89]

During the spring of 1961, the architects began preparation for the final stage of the concrete drum—the application of a liquid sealant called Thoroseal. [90] According to Dion Neutra and the product manufacturer, success depended on the effect achieved prior to the application of this final layer. Unfortunately, "the horizontal pour joints read clearly on the ribbed concrete areas between ribs especially on the Cyclorama drum, and rear wall of Auditorium and Mechanical. These must be ground flush afterpatching voids to correct for any possible variation in plane of one pour to the next. While the ribs will tend to overpower slight imperfections, there must be no 'ghost' of the horizontal 'bands' now quite dominant in the picture." Before applying Thoroseal, the firm recommended grinding six inches above and below the visible joints and performing "heavy sandblasting to effectively remove all traces of form oil down to clean concrete." [91] Finally, in May, a product representative of the Thoroseal company applied test samples of the product over certain construction joints to see if it would adequately mask surface deformities. According to Standard Dry Wall Products, the first coating of Thoroseal could be painted on, but a second coat required use of a plastering spray gun that blasted a mixture of Thoroseal and white silica sand. [92] While working with the samples, Gamble discovered "rough bulging patches" that required smoothing out, and recommended bush hammering. The rougher surface would provide a better bond for the Thoroseal. [93] During his next inspection, just a week before Richard Neutra was expected at the site, Longstreth found the surface unacceptable. He predicted that

the expression of the construction joints will telegraph through the final finish particularly because of the irregularities not in the surface between the ribs but of the ribs themselves which cast elongated shadows to accentuate their irregularities. These occur repeatedly at all construction joints and make a staccato shadow pattern at each joint around the drum. Unless the patching of the ribbing is perfect it is felt that this staccato pattern will show through final finish. [94]

Even after a September visit from the EODC to address problems with the application of Thoroseal, Superintendent Myers was still dissatisfied with the exterior finish. Visible shadows and other defects obviously compromised the effort to obtain a smooth concrete surface. Nevertheless, the Superintendent promised that if the contractors could apply another coat and achieve a surface similar to "the northern most of the 12-foot experimental panels," he would accept the job. [95] Project supervisor Smith personally observed the painting foreman, a subcontractor, apply three coatings of Thoroseal just north of the approved northern-most panel. In a follow-up report, Smith described unsightly build up and shadows in the new work. [96]

The Thoroseal problems appear to have been resolved by early December; when Neutra visited the site, he reported the job "favorable and engaging." [97] Most important to Neutra was the opportunity to test lighting conditions, particularly in the exhibit spaces, and color effects, both of which could only be properly evaluated on site. At this point, exhibit frames and dioramas were complete enough for paint analysis. Neutra's letter included a summary of qualities that "obviously put this building outside of the common run of projects," such as the audiovisual system, "the installation of the gigantic painting, the final testing of large dimensioned sliding and swinging doors, the perfection of the finish metal work, intended for long lasting sightliness without running upkeep, of roof viewing decks, etc." [98]

CONTINUED continued



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