Armstrong Cork Company, Pittsburgh Pennsylvania

Date added: January 20, 2023 Categories: Pennsylvania Industrial

Cork is a natural product, the porous outer bark of the cork oak, an evergreen tree grown primarily around the Mediterranean. Natural cork is harvested easily and can be processed simply, and has been used for fishing floats and as stoppers for containers since before the start of recorded history. For a variety of reasons, Pittsburgh became America's largest producer of commercial glassware in the mid-19th century, especially glass bottles and jars. The growth in Pittsburgh's demand for cork for bottle stoppers and jar lid liners was a natural offshoot of the glass industry. Processed food manufacturers, such as Pittsburgh's H. J. Heinz Company, increased the local need for cork. Late in the 19th century other uses for cork emerged, including linoleum and other patented flooring, acoustical and thermal insulation, gaskets for machinery, and stuffing for life jackets.

Pittsburgh's Armstrong Cork Company evolved from a one-room workshop in 1861 where John D. Glass cut cork bottle stoppers. Thomas M. Armstrong, a $12 per week clerk in a local glass factory, apparently provided $300 to start the business. When Mr. Glass died in 1864, Thomas Armstrong quit the glass company, and with his brother Robert and a third partner began a full-time cork business named Armstrong, Brother & Company. The Civil War created a huge demand for cheap liquor and patent medicine bottles, many of which were made in Pittsburgh, and Armstrong's company provided bottle stoppers. The business was located in a three-story building at 122 Third Street in downtown Pittsburgh for a time, and then moved to a location on nearby First Avenue. Obtaining adequate supplies of cork was a problem, and starting in the 1870s Thomas Armstrong employed native European buyers, paid by commission, to acquire cork for the company. Thomas Armstrong also worked to establish a reputation for quality and fair dealing. Armstrong corks were branded with a trademark at a time when many similar products were packaged anonymously and sold by weight. A written guarantee of quality was included in every bag of Armstrong corks.

Cork dust is highly inflammable, and in 1878 the First Avenue building burned. The Armstrongs needed railroad access for cork delivery, and more space for their business than was conveniently available in downtown Pittsburgh, and as a result bought a block of property in Pittsburgh's Strip District, between 23rd and 24th Streets at the Allegheny River. The first Armstrong building, adjacent to 24th Street, opened on this site in 1880. Cork arrived in Pennsylvania Railroad boxcars from tracks just in front of the factory, parallel to appropriately-named Railroad Street. Just west, on the opposite side of 23rd Street, was a lot filled with railroad sidings. Individual boxcars were shunted from the sidings onto a track that ran north-south through the middle of the block between 23rd and 24th Streets, parallel with the company's building. During this era Armstrong's primary business was providing cork stoppers for soda and beer bottles, fruit jars, and beer kegs. Armstrong, Brother & Company was the largest cork manufacturer in the United States. When stoppers were replaced with metal crown caps in the 1890s, Armstrong provided the cork lining. The company also manufactured bicycle grips for the cycling craze that swept the country in the last two decades of the 19th century. Cork processing created a lot of scrap material, and the company experimented with its waste pieces. In the 1890s the company advertised cork shavings as a healthy, comfortable, and cheap mattress stuffing. To counter the price fluctuations of the Panic of 1893, the Armstrongs formed an international syndicate of cork manufacturers known as the American Cork Company. Fears that the price-controlling syndicate would be found to violate the Sherman Anti-Trust Act led to the incorporation of the Armstrong Cork Company in 1895. The new company merged the operations of most of the syndicate members under Armstrong's leadership. Thomas M. Armstrong headed the company, and his son Charles D. was First Vice-President. The new company included four small cork producers in Lancaster, Pennsylvania that became Armstrong's Lancaster Cork Works.

The building constructed in Pittsburgh's Strip District in 1880 burned in 1901, just as the Factory, the oldest surviving building on the site was being built on the 23rd Street side of the city block the company owned. The huge Warehouse was completed only one year after the Factory, on the site of the burned building. At the time, the complex also included five ancillary buildings: the Engine Room, Boiler House, Mill Building, Oven Building, and the Headquarters Building. Bales of raw cork were moved from rail cars into the Warehouse via its loading dock. The cork was sorted by grade in the Warehouse and moved to the seventh floor, where the material passed over the yard between the Warehouse and Factory via one of the metal truss bridges. The sorted cork was delivered to the designated section of the Factory, processed, and then the trip was made in reverse with the finished product. The Factory is narrower than the Warehouse, is more evenly illuminated in daylight, and in the early years was where much of the finishing work was done.

While the Pittsburgh operation concentrated on making stoppers and seals, in 1900 Armstrong acquired a patent for manufacturing corkboard. In 1903 a new plant was constructed in Beaver Falls, Pennsylvania to manufacture corkboard insulation from scrap cork. At the time, most of this product was used by breweries. Armstrong's first ever scientific tests, conducted in Pittsburgh, measured the heat transfer through corkboard to document the product's insulation qualities.

The year 1904 was an important one for Armstrong Cork Company. In that year it purchased the Nonpareil Cork Manufacturing Company in Camden, New Jersey in order to acquire the patent on a superior process of corkboard production and become the dominant domestic manufacturer of that product. Most importantly to the company's future, Charles D. Armstrong convinced the Board of Directors to enter the linoleum business. The decision was driven at least in part by the growing Prohibition Movement and the belief by Charles Armstrong that the company's profits were tied too heavily to the beer and liquor industries. Producing linoleum also would consume the waste cork dust (or "flour") that Armstrong was then either dumping or selling to existing linoleum manufacturers. The linoleum decision was not an easy one, required all Armstrong's excess capital, and would not show a profit for over a decade. Manheim Township near Lancaster was chosen as the site for the new linoleum factory. The site was near Armstrong's Lancaster Cork Works, land was readily available there, and there were comparatively few local heavy industries to compete for workers.

The move into flooring led to the logical splitting of the Armstrong Cork Company into three domestic divisions: Insulation, Flooring, and Corkwood. The Pittsburgh plant would continue to lead the Corkwood division, while the Lancaster facility was the Flooring headquarters. The linoleum decision also was a clear indication that the Armstrong Cork Company would not tie its future solely to cork. Over time, the company sought to control the costs of linoleum by manufacturing the linseed oil, paint, and other components used in linoleum production. These steps would lead to further diversification.

A glimpse inside Armstrong's Pittsburgh facility is obtained from an important contemporary account in Women and the Trades, Pittsburgh 1907-1908, a book published as part of the Russell Sage Foundation's seminal Pittsburgh Survey. Although Armstrong is not mentioned by name, under a chapter sub-heading "Cork":

The largest cork factory in the United States occupies two seven-story brick buildings near the riverfront in Pittsburgh. The employees number 600 girls and 800 to 900 men. From floor to floor, the river breeze sweeps up wide staircases and through open windows into high-ceilinged rooms. You can see lanes of power-driven machines, cutting, shaping, polishing corks cutting cork paper, shaping cork soles....

Binding cork with glue and other material under heat and pressure produced durable cork compositions. The discovery of this process in 1912 expanded the market for cork-containing products in the automobile, textile, shoe manufacturing and processed food industries. Using this technology, Pittsburgh's plant produced millions of shoe insoles. An Armstrong-invented cork composition replaced sheepskin and leather for roll coverings in the textile industry. The cork composition business likely led to the construction of the third major building in the Pittsburgh complex, and its tallest, the ten-story Tower, completed in 1913. The lower seven floors of the Tower apparently are where much of the experimentation with cork composition took place. A special laboratory was constructed on the 8th floor of the Tower, and a separate Laboratory building was built in 1918. The top two floors of the Tower housed executive and managerial offices for the growing company, served by the separate entrance and elevator lobby off 24th Street.

Despite all the new uses for cork, the core business for the Pittsburgh plant remained producing millions of stoppers and cap liners for the processed food and beverage industry. Armstrong's leadership of the national cork industry is revealed in the 1914 Census of Manufacturers. Although the facilities in the census are not named, a chart categorizing the size of plants by number of employees found one cork plant (Armstrong's Pittsburgh facility) with 1,135 employees, while the next three factories combined employed 908. It is likely that at least two of the three smaller factories were Armstrong's Lancaster, Pennsylvania, and Camden, New Jersey plants.

During the first decade of the 20th century Armstrong Cork Company expanded its holdings in Spain, and in 1914 began manufacturing corkboard at a factory in Seville. More investments in Spain and in the cork producing regions of North Africa would follow.

Demand for Armstrong's products increased during World War I. The Lancaster plant added an artillery shell production line by buying the appropriate machinery, hiring a few experts to run the line, and then training existing employees. In the 1920s Armstrong remained the world leader in cork production, consuming 10-12% of the world's strip cork (for cork stoppers, etc.) and 60% of the world's grinding cork. Armstrong purchased port and warehouse facilities near its Camden, New Jersey plant and in Spain so that the company could control the shipping and storage of cork, insuring constant supply. The introduction of electric refrigerators in the 1920s provided a new market for cork insulation, until cheaper fiberboard insulation was found to perform adequately. A new product "Corkoustic" was developed in Pittsburgh in 1928 and marketed to the growing radio industry for studio soundproofing. The original Cork Division was subdivided into four new divisions: Closure, Textile, Shoe Products, and Industrial. Almost immediately the new Industrial Division began to diversify out of cork, investigating and investing in other materials.

In 1928 Armstrong Cork Company made the decision to move its corporate headquarters to Lancaster, Pennsylvania. In March of 1929 sixty-five Armstrong executives, their families and household goods, were moved to Lancaster from Pittsburgh. The primary reason for the move was the pre-eminence of the Flooring Division; by the late 1920s Armstrong was the national leader in linoleum production. Additional contributing factors were the fact that the Pittsburgh complex was land-locked and could not be expanded, the closer proximity of Lancaster to the major markets of New York City, Philadelphia, and Baltimore, and (possibly) the declining health of Pittsburgher Charles D. Armstrong.

During the expansion under Charles D. Armstrong's leadership, the company continued to stress the fair dealing with customers and fair treatment of employees policies of Thomas M. Armstrong. The company promoted employees from within whenever possible, and gave local superintendents more autonomy than most contemporary industries.

Armstrong supported employee bands, athletic clubs, dramatic organizations, and other activities. A cafeteria for employees was installed in the Pittsburgh plant in the 1930s. A training facility for executives and salesmen was established in Lancaster, and the company actively recruited on college campuses. A company focus and important to the education of salesmen was educating customers on how they, the customers, could profit from Armstrong's products. In 1929 the company announced a comprehensive insurance program for its employees; health, retirement, disability, and even car insurance would be provided through the Metropolitan Life Insurance Company. The program was to start in 1930, and the effects of the Depression caused its cancellation.

The stock market crash in 1929 had little immediate effect on the Armstrong Cork Company. However new orders declined in 1930 and hit bottom in 1932 when the year produced only one-third the sales of 1929. Employment in Armstrong's United States plants fell from 6,805 in 1929 to a low of just under 3,800 in early 1933. Stock value plunged from $76.00 a share in 1929 to $3.25 in 1932. Sales by the Flooring Division carried the reduced company through the worst of the Depression. Business for the Pittsburgh plant increased with the repeal of Prohibition in 1933, which increased the demand for cork-lined crown caps, cork bungs for beer barrels, and stoppers for liquor bottles. The Cork Division developed turf for the miniature golf craze that swept through America in the 1930s. A Pittsburgh newspaper article in 1936 noted that the plant employed 1,250, and half of the Pittsburgh business was producing cork stoppers and cap and jar liners. The article noted that "Products of the local factory are sold in every major industry in the United States." The Pittsburgh plant was closed for days by the famous St. Patrick's Day flood in 1936. Bales of cork bobbed down the flooded Allegheny River, lifted by the rising water from rail cars at Armstrong's plant. In the late 1930s the company acquired two glass manufacturing plants, further diversifying its holdings. Jar and bottle makers had begun providing caps and lids for their products, and for Armstrong to continue to have a market in the "closure" field it needed to make its own glass vessels.

In 1940 Armstrong Cork Company remained America's largest importer of cork, and largest employer of cork workers. However, the company's growth and diversification meant that cork represented only 13% of its purchases of raw material, and no cork was used in 78% of its sales by dollar volume.

Although it has not been thoroughly documented, the 1940s were a decade of major changes in Armstrong's Pittsburgh plant. The entire facility was in essence commandeered for World War II production, and it became a fenced and guarded national defense plant. In 1943 the Garage was constructed on part of the site once occupied by the Office building, just north of the Factory. The Garage provided the Factory building with loading docks, something the building lacked. A plastic / Plexiglas manufacturing and finishing facility was installed, and aircraft windows, bomber gun turrets, and other finished pieces were produced. The Pittsburgh factory submitted sample mortar shells to the War Department for approval, but it is not clear that a manufacturing line was installed. Cork also was in extraordinarily high demand for food and beverage containers, life jackets, insulation, engine gaskets, and a wide variety of other purposes.

Armstrong's Pittsburgh plant returned primarily to cork processing after World War II, while corporately Armstrong Cork veered further away from its legacy cork products. After World War II Armstrong developed, refined, and put into production several different lines of acoustical ceilings; none used cork. Cork board insulation became obsolete as fiberglass and later foam insulations were developed. Armstrong opened a flooring plant in England and began to sell off some of its cork holdings in Europe and North Africa. The company began manufacturing asphalt-based floor tile in the 1930s and immediately after the end of World War II built two new plants, one in the Midwest and one in the south, to produce asphalt tile. Two new sheet flooring plants also were built in south, and a third was constructed in Montreal, Quebec, Canada. The first Armstrong vinyl flooring reached the market in 1951. In addition to the cork and flooring operations, the company acquired and operated furniture and carpeting factories. It also manufactured the paint used in its flooring factories. In this period the original three divisions were reconfigured, added to, and expanded. In the post World War II boom, the Industrial and Building Materials divisions became increasingly important to the company's success. By 1947 Armstrong operated 17 plants in the United States, producing various types of flooring, ceiling tile, paint, glass, wood composition building materials, furniture, carpeting, and cork products.

In the late 1940s Allegheny County instituted tighter smoke controls, one component of its heralded post-war Renaissance. Armstrong was required to install more efficient cork dust collection equipment, and other pollution controls. As part of the effort to reduce pollution, the Pittsburgh plant stopped generating its own electricity from its on-site coal-fired boilers, and converted to the local electrical utility. This required the construction of the Transformer Building, attached to the Factory. River pollution also came under scrutiny.

Research in cork continued. In the 1950s, product engineers in the Pittsburgh facility perfected a dielectric process for producing cork composition which eliminated hours of steam baking and resulted in a more consistent product. This advance was particularly applicable to producing engine gaskets. At some point, the plant introduced a urethane production line, perhaps based on the plastics technology introduced during World War II. Through the 1960s and into the early 1970s, the plant made gaskets, gasket material, and seals for all the major automakers, heavy equipment companies, and many of the large commercial electronics and appliance manufacturers. High technology ablation materials were developed in Pittsburgh for the aerospace industry. These special materials protected rockets and aircraft by rapidly dissipating the heat generated by high speeds.

Pittsburgh's Armstrong facility was functionally obsolete by the 1960s. The buildings had been designed for large numbers of workers cutting cork by hand or with simple machinery, using natural light as much as possible. As synthetics replaced natural cork in a number of applications, the hand work ended. Multi-story processing and manufacturing facilities like the Armstrong plant required frequent and inefficient handling of material, interrupting production lines. Interstate highways reduced industry's dependence on railroads. Armstrong apparently began to phase out the Pittsburgh operations in the late 1960s, making minimal investments in the facility from that period. When the Pittsburgh plant finally closed in 1974, only 300 employees worked there, many were women, and many had 25 years or more of service. A company history noted that "....its string of cork products was finally exhausted, despite continued efforts - sometimes more sentimental than economic - to keep that link with the past alive." A series of auctions were held to sell off the equipment and machinery in the Pittsburgh factory. In 1977 Armstrong Cork Company was renamed Armstrong World Industries.

The Pittsburgh buildings passed through a several owners after 1974. Part of the first floor of the Factory was used as a grocery warehouse for a time. Most of the complex was unused, and it received no maintenance. Despite attempts to secure the property, the buildings served as a refuge for the homeless and a playground for restless teenagers from the 1980s through 2004.

Building Description

The former Armstrong Cork Company is a complex of buildings on a 2.5 acre site in Pittsburgh's Strip District. The complex is bounded to the approximate west by 23rd Street, to the east by 24th Street, to the south by Railroad Streets, and to the approximate north by the Allegheny River. There are three large, multi-story buildings in the complex, six smaller or ancillary buildings, and one structure, a 200-foot tall brick smokestack. All the buildings in the complex are constructed of hard, bright orange brick. The stack is built of buff brick. The three main buildings are the Romanesque Revival Factory (1901) and similar Warehouse (1902), and the Tower (1913). The Tower has Beaux Arts decorative elements. The three main buildings were designed by Pittsburgh architect Frederick J. Osterling. The Armstrong company sold the property in 1974, and it has received no maintenance of any consequence since that year. Materials and workmanship have been compromised by lack of maintenance and vandalism.

The Factory was constructed in 1901, is approximately 60 x 292 feet, and is divided in half by an internal partition. The Warehouse dates to 1902, is 85 x 305 feet, and is divided in three parts by internal walls. The exterior appearance of the two buildings is very similar. The Warehouse and Factory are seven-story tall, long, parallel buildings that define the site, creating a mostly-open yard between them. The Factory has a long elevation along 23rd Street, and the Warehouse has the same along 24th Street. Two steel truss bridges connect the Warehouse and Factory across the yard at the seventh-floor level. The bridges are not included in the resource count of the nomination. The third main building, the ten-story Tower, built in 1913, measures 67 x 118 feet, and is connected to the north end of the Warehouse.

The Factory is eighteen bays long and three bays wide. On the north, south, and west elevations, the rough-faced granite block foundation and the lower two floors form a base, defined by a projecting terra cotta water table. The east elevation, facing the yard between the Factory and Warehouse, has a lower and less visible granite foundation and no water table. Each bay of the first floor of the west elevation has a pair of rectangular windows in a rectangular masonry opening. Modern garage doors were installed in some first-floor bays in the 1940s and 1950s. The second floor has a pair of rectangular windows in a shallow-arched masonry opening. Above the water table each bay of the third through sixth floor is framed by brick pilasters that are connected by an arch at the sixth floor. Each bay of the third through sixth floor has two arch-topped windows, each in their own shallow-arched masonry opening, the whole recessed from the bay-forming piers. Infilling the arch of the sixth floor is a three-part window that follows curve of the masonry arch. There is a corbelled brick belt course above the sixth floor. The top floor features paired circle-topped windows set in flush brick in each bay. Capping the masonry composition is a corbelled brick cornice that is topped with stone coping. The center two bays of the west elevation have the building's historic entrance, where employees entered, now bricked-shut and obliterated. Above the old entrance are paired recessed balconies on each floor, creating an opening in the exterior elevation from the second to the sixth floors. The balconies in the opening have concrete decks and iron railings. The seventh-floor balconies are behind the paired circle-topped openings common to the floor. These balconies served as part of the internal stair system, and had the practical function of isolating the stairs from direct entry into each floor; an advantage in a fire or other emergency.

The window spacing and configuration of the north and south three-bay elevations match the west elevation. There are no entrances or recessed balconies on these elevations. The garage covers the first floor of the north (river) elevation. The east elevation (courtyard side) is simpler. It is flush brick with paired arch-topped masonry openings on floors one through six, and paired circle-topped openings on the seventh floor. There is a double steel door under a masonry arch in the first floor of the sixth bay from the south. There are two elevators in masonry shafts attached to the exterior at the south end and at the third bay from the north end of the building. The elevators have blind window recesses on the courtyard side of the enclosed shaft. Some of the east elevation is obscured by the attached courtyard buildings: the Mill Building, Boiler House, Engine Room and Transformer Building.

All of the windows in the Factory originally were wood-sashed. The surviving 6/6 double-hung sash is in very poor condition. The building originally had steel shutters for all the windows, and the pintles remain in the masonry, though the shutters are long gone. Many openings, particularly on the yard side of the Factory, have been altered. The composition roof is nearly flat; it is slightly sloped to run to scuppers and internal roof drains. The roof has a tall elevator penthouse and eight steel-framed gabled skylights along the longitudinal centerline of the building. The skylights and roof covering are in poor condition.

The interior of the Factory was minimally finished originally and virtually no historic material survives. Walls are painted brick, floors and ceilings are poured concrete. Rooms were constructed within the space as needed for the various functions, but most of the floor space is open. The Factory had two sets of steel stairs housed in brick towers. It was not possible to enter directly from the floors. Access was gained through a fire door opening from each floor onto the balconies visible on the exterior. A second fire door opened into the stair tower from the balcony. All of the steel stairs in the Factory and Warehouse were stolen for salvage, leaving just the skeletal riser supports in the stair towers. The building had two internal elevators adjacent to the stair towers in addition to the two elevators in masonry shafts projecting from the Factory's east wall. The north (river) end of the seventh floor of the Factory had the complex's cafeteria, apparently built in the 1950s. The entire building is strewn with debris and decorated with graffiti.

The Warehouse was constructed in 1902 on the site of the original Armstrong building on the site, built in 1880. The original building burned to the ground in 1901. One bay wider and one bay longer than the Factory (4 by 19 bays), the exterior details of the Warehouse are simplified from the year-older Factory, and resemble the east face (courtyard side) of the Factory. The Warehouse exterior masonry is flush, without the pier-forming recesses of the three more public elevations of the Factory, and without the sixth-floor arches and tripartite windows. The windows on all but the top floor of the Warehouse are arch-topped (although the sash is not arched), and are paired in each bay. The top floor has circle-topped openings and sash, like the Factory. The Warehouse brick appears to be identical to that in the Factory. All three of the exposed elevations continue the described bay pattern. The north elevation of the Warehouse is entirely covered by the south elevation of the Tower.

The yard side of the Warehouse has three elevators in masonry shafts attached to the exterior, and a steel truss shed roof over a concrete loading dock running the length of the building. Originally there was a railroad siding in the yard, and cork bales were off-loaded onto the Warehouse loading dock from rail cars. Access to the Warehouse was through three entries with paired steel doors from the loading dock. The building has no large public entrance. The 24th Street elevation has a pair of recessed balconies, identical to those in the Factory, plus an additional single recessed balcony; all marking stair locations. The pair of balconies is located at the eighth and ninth bays from the south elevation, and the single balcony is in bay fifteen.

One of the main differences between the Factory and Warehouse are the windows. The Warehouse received unusual patented hollow steel sash, apparently designed to be fire and explosion-proof. These windows were designed to look like the 6/6 multi-light wood windows in the Factory. The windows have not survived well. To install the individual lights, a panel on the top of each sash was removed, and the lights slid in place down channels formed by the vertical muntins. These windows apparently obviated the need for steel shutters, and there are no shutter pintles embedded in the Warehouse exterior. Many of the window openings have been altered by the installation of fans and other equipment.

The roof of the Warehouse is similar to the Factory: composition roofing, sloped to scuppers and internal roof drains. The roof is divided into three parts, matching the internal division of the building. There are two existing square, flat-roofed skylights and the roofed-over holes where two other skylights once were.

The interior of the Warehouse is more accessible than the Factory, and is in worse condition). There is essentially no historic fabric within the Warehouse. The walls are painted brick and the floors and ceilings are concrete. The building is divided into three parts, and each had a set of the same steel stairs accessed by open balconies that existed in the Factory. The stairs in the Warehouse also have been stolen by salvagers. As in the Factory, there was an interior elevator constructed in a shaft adjacent to each set of stairs. A number of interior partitions have been constructed of cinderblock or wood on an apparent as-needed basis. There are holes cut between the floors in several locations to accommodate large pieces of equipment. The equipment does not remain in the building.

The steel truss bridges connecting the Warehouse and Factory are sided with corrugated metal, and are roofed and floored with wood. Pedestrians walked through the trusses. The bridges appear on a 1906 insurance atlas map, and were used to move material from the Warehouse to the Factory and back without taking it across the yard. The bearing capacity of the bridges was limited, and in later years Armstrong used special lightweight forklifts to move material, and limited the number of people allowed on a bridge at the same time. There is no provision for expansion and contraction in the bridges, and the masonry anchor points at the Factory and Warehouse are damaged. They also have been subject to the long period of neglect and vandalism.

The Tower was constructed in 1913, is ten stories tall, and has a 67' by 118' footprint. It is attached to the north wall of the Warehouse, and occupies the site of the one and two-story Oven Building. The major difference between the Tower and the Factory and Warehouse is that the Tower is constructed with a steel frame and masonry curtain walls, so the exterior walls are thinner. This is particularly noticeable from the inside at the window openings. The Tower lacks the arched or circle-topped windows, and is trimmed with terra cotta in Beaux Arts detail. The lower seven floors are connected to the Warehouse, and seem to have been used for experimentation with and production of cork composition. The top three floors housed a laboratory and the executive offices for the plant.

The exterior of the Tower has four bays facing east-west, and seven facing north-south. It appears to be constructed of the same brick used in the Factory and Warehouse. Each bay has room for two rectangular window openings, though apparently the building housed a lot of equipment, and many of the masonry openings were left filled-in when the building was built, particularly on the west wall. The curtain wall construction made it easier to cut window openings in the Tower than the Warehouse or Factory. The Tower has a wider east-west footprint than the attached Warehouse, exposing two bays on its south elevation, west of the west wall of the Warehouse. Above the height of the seven-story Warehouse, the south elevation of the Tower has the same bay configuration and window arrangement as the other elevations. Simple projecting terra cotta belt courses mark the second and seventh floors (the latter marking the height of the roof of the Warehouse). Above the seventh floor the bays are marked by projecting brick pilasters. The pilasters are capped with shallow buff-colored, terra cotta Ionic capitals above the tenth floor. The capitals are connected by a horizontal band of terra cotta. The parapet is capped with terra cotta coping. The Tower has the only architecturally formal entrance to the complex. This entrance faces 24th Street, and has a well-detailed, dentiled, white terra cotta Greek Revival pediment the full width of a bay. Recessed below the pediment is a tall transom with a Beaux Arts muntin pattern. The entrance housed a pair of doors, and led to a narrow lobby and the small passenger elevator that served the upper-floor executive offices.

The Tower has a different variety of the hollow steel windows used in the Warehouse. These tall windows have a 3/3 configuration.

The interior of the Tower contains most of the interior historic fabric in the complex. The terra cotta pedimented entrance leads to a small marble-floored lobby with built-in wooden benches. The area has been thoroughly vandalized. Beyond the small passenger elevator is a full set of stairs of near monumental proportions in a large well located against the center of the south wall of the building. The open well, three-flight-per-floor stairs are six feet wide and featured slate treads and landings, and cast steel balusters. The handrail for the office portion (floors 8-10) is capped with oak. Below the seventh floor, salvagers used the stairwell to drop radiators or other heavy pieces of equipment to the ground floor. As a result, the slate landings below the seventh floor are destroyed, and their steel supports bent and damaged.

Beyond the small lobby area, the lower seven floors of the Tower were connected to the Warehouse. The Tower had more specialized machinery and testing equipment than the other buildings that were used mainly for storage and processing. This equipment changed over time, and its vestiges are a few cinderblock rooms, holes in the floors, studs in the floor where equipment was bolted, and the remains of ventilating and air filtering apparatus. The top three floors housed office functions, and were furnished with steel or wooden moveable partitions, and, appropriately, acoustical ceilings and cork flooring manufactured by Armstrong. The interior columns on the top two floors were faced with yellow brick veneer, and had a small and very simple capital at the ceiling. As is the case with all the buildings in the Armstrong complex, the interior of the Tower has been vandalized and spray-painted with graffiti. The office floors of the Tower have been subject to more weather damage as the building is exposed on all sides and nearly all the windows are broken or missing.

The Mill Building, Boiler House, and Engine Room were constructed in 1901 on the east side of the Factory, in what would become a yard space when the Warehouse was constructed. All are constructed of the same orange brick used throughout the complex. The Boiler House provided steam to the plant for heat. Some of the steam-powered electrical generators in the engine room which provided power for the complex's machinery. Ground cork was collected and baled in the Mill Building; this function apparently was isolated because of the danger of a dust explosion.

The Mill Building is northernmost (nearest the river), has three stories, and is three bay wide and four bays long. Each bay facing the yard has a pair of rectangular window openings, except the easternmost, which has no openings. The north elevation has a single window in each outer bay, and a shallow-arched, wide door opening on each floor in the center bay. The Mill Building has a corbeled brick cornice, which steps up slightly in the center of the west elevation. The south and west elevations are hidden or covered by the Factory and Boiler House. The flat roof was used for dust collecting apparatus. The interior had open wooden floors, now almost impassable with debris. The building is not in good structural condition. The east wall has been repaired once, and it is falling away from the rest of the building, in part because a support for one of the overhead bridges is attached to the wall.

The Boiler House is in the middle of the three 1901 buildings. It is essentially three stories tall, and has one exposed wall facing the yard. The exposed wall has two gables, flatted across their tops, into which monitor roofs are built. The monitor roofs have two banks of once-operable panels that provided ventilation for the Boiler House. There are two rectangular openings of different sizes filled with rolled steel sash windows. The original boilers were replaced after World War II. The east wall (courtyard side) of the Boiler House was rebuilt in 1946. The interior of the Boiler House is open from top to bottom, and is filled with the remains of Armstrong's boiler equipment.

The Engine Room is a one-story, four by four bay building with a tall hipped roof. It measures 54 by 62'. The hipped roof is built over a steel truss which provided a clear span over the generators once located here. It has a concrete floor. After Armstrong converted to outside-supplied electricity this became the plumbing shop.

The Laboratory is a one-story building located between the north end of the Factory and the river. It was built in 1918, and was attached to the now-gone headquarters building that stood north of the Factory. It is 24 x 39', built of brick on a concrete foundation, with steel trusses supporting the roof. The gables on the north and south ends step up in the middle. The west wall had six large vertical window openings, filled with rolled steel sash. The northern opening is infilled with brick. The interior has a large concrete pit, and odd changes in floor level.

The Garage was constructed at the north (river) end of the Factory in 1943. It is one story tall, built of brick, 38 x 37', with a wood truss roof. The west face, facing 23rd Street has a loading dock-height garage door, flanked by vertical rectangular windows filled with rolled steel sash. The north wall is featureless. There is nothing of interest in the interior, other than the roof, which has collapsed into it.

The Transformer Building is a one and two-story 32 x 23' brick building added in 1946 to the east face of the Factory at its south end. The building housed electrical apparatus added after Armstrong converted their plant to commercial power after World War II.

The smokestack was constructed in 1915 between the Boiler House and Factory to vent the boilers. It is 200 tall, approximately 16 in diameter at the base, and is constructed of buff fire brick. Records indicate the stack was inspected and partially repointed in 1964, and steel bands were added and more pointing done in 1967.