The Assembly (Auditorium) Building was one of the eight Nelles-era school buildings that remained on the site after the campus was modernized by the California Youth Authority. It was one of the several buildings added to the complex in the 1920s and 1930s during and following Fred C. Nelles’ tenure as superintendent (1912 to 1927) to improve the school and fulfill his ideal of a cottage system. As the goal of the cottage system was to inspire community and a sense of family among the wards, the main community space for the wards figured prominently in their experience of the institution. The Assembly (Auditorium) Building was an important facet of that sense of community; and its small proportions and references to ecclesiastical architecture reinforced its connection to historic community centers.

Architectural Character

The tall one-story Assembly (Auditorium) Building was influenced by the Tudor Revival-style, as well as the Mediterranean Revival-style. The steeply pitched front gable roof was clad in red barrel tile, and its shape and massing echoed the Administration, Old Infirmary and Chapels Buildings, which were situated nearby on the Nelles campus. The building had a small side-gabled project on the north elevation that housed an interior stairway to the balcony level and was non-original. The Assembly (Auditorium) Building rested on a poured concrete foundation and was originally constructed of unreinforced brick masonry. During the 1950s the building was structurally retrofit with gunite and concrete buttresses built between the window bays of the north and south side elevations. The exterior of the Assembly (Auditorium) Building was covered with gunite in 1952 as part of a structural retrofit campaign.

The plan of the Assembly (Auditorium) Building mimicked ecclesiastical architecture, and it was sometimes referred to as the main chapel assembly building. The steeply pitched gable roof and side entrance tower were arts and crafts inspired features, and were also references to English country chapels. On the front façade, the gothic tracery of the vent, the round arch over the central entrance doors, and the stone quoins around the doorway (now removed) were reminiscent of the architecture of Christian churches in Europe. Those features referenced its status as a meeting place for community activities within the school complex.

The entrance into the Assembly (Auditorium) Building was located on the primary (east) elevation and featured a slightly projecting center front gable which contained a deeply recessed arch entryway (alteration) with a pair of contemporary metal doors. The un-ornamented archway was flanked by small one-over-one fixed wood sash windows glazed with wire glass (alterations, the windows were replaced and the lintels removed). High above the arched entryway was a small, deeply recessed roundel opening with tracery inspired by tracery in Gothic architecture and at the peak of gable was a small horizontal slat-vent (alteration, non-original).

The north (side) elevation featured three steel-framed multi-light fixed and awning windows separated by concrete buttresses, while the south (side) elevation had five steel-framed multi-light fixed and awning windows also separated by concrete buttresses. To the far east of the north elevation was the side-gabled projection (alteration, non-original) that featured a contemporary metal door on its east (front-facing) elevation and two small, recessed, non-original, wood sash windows on its north elevation. To the direct east of the gabled projection on the north elevation was a wood sash window. The west end of the south (side) elevation had two recessed entries with contemporary doors.

The rear (west) elevation was mostly plain with two small deep-set windows on its right (south) side. There were also several vents along this elevation, including a large vent near the gable peak. At this elevation, the basement level was accessed by a below-grade walkway with concrete stairs.

The interior of the Assembly (Auditorium) Building included the entrance foyer, the main Assembly (Auditorium) Building hall, stage, and two dressing rooms. The floor of the Assembly (Auditorium) Building was raked or slanted towards the stage platform on the southwest end of the building and was covered in non-original vinyl floor tiles. The Assembly (Auditorium) Building had exposed steel truss-work supporting the roof, which gave the room a similar appearance to the gymnasium. Rows of non-original wood-and-metal folding seats lined the auditorium floor. The central space of the Assembly (Auditorium) Building was mostly utilitarian in appearance, lit with windows (alterations) on both the northwest and southeast walls. The stage, on the southwest end of the building was framed by rectangular opening which created the performance space.

Floor Plans

The Assembly (Auditorium) Building had an overall rectangular plan with an open, double-height interior and balcony. The first space entered from the primary (east) elevation was a small, almost square entry room. The double-doors of the entry room opened into the main auditorium space where the floor had a gradual rake leading to the stage area. On either side of the entry were two private offices with restrooms and a fan room. The balcony that once housed the projection room was located along the east wall, above the entry and private offices. The west wall of the auditorium featured the raised stage and within this stage area were two private dressing rooms. Underneath the stage was a small, partial basement with an exterior access stair at the rear of the building; it contained a “fan room” where machinery for ventilating the building was located.

Historical Landscape Design

The Assembly (Auditorium) Building was set behind a grass lawn in the shape of a triangle created by the intersection of two historical roads. The Assembly (Auditorium) Building retained its historical relationship to the roads and open landscape. From the analysis of historical aerials, the Assembly (Auditorium) Building retained two concrete pathways: an east-west pathway leading from the primary entrance to the street and a portion of north-south pathway (the northern portion of the pathway was removed when the new improvements were constructed). The sidewalks along the perimeter did not appear to be original, as well as the various trees scattered around. Historically, the east side of the block was lined with palm trees, which no longer exist. The landscape immediately adjacent to the Assembly (Auditorium) Building was disrupted by the construction of the classroom buildings to the immediate north, west, and south between 1958 and 1962. At the time the conical tower and one-story wing was removed in 1952, flower beds were improved along the side (north and south) elevations of the Assembly (Auditorium) Building.

Additional Information

For more historical information, including more building specifics, floor plans, and photos, download the HABS Report and reference page 123.

Physical History

Date of Erection

Constructed circa 1923


George McDougall

Builder, Supplier, & Contractors

The Division of Architecture at the State of California Department of Public Works



The Assembly (Auditorium) Building was primarily rectangular in plan with overall dimensions of approximately 110 feet long by 48 feet wide.


The Assembly (Auditorium) Building sat on a concrete foundation.


The exterior walls were unreinforced brick masonry wall structure with cast-in-place concrete buttresses along the north and south elevations. During the 1950s the existing walls were retrofitted with new structural gunite applied to the exterior of all elevations and the out course of brick was removed.

Structural System & Framing

The building’s gravity system consisted of wood beams over long-span steel trusses; the trusses were supported on concrete pilasters located within the brick unreinforced masonry walls. At the east and west end of the building, framing bears were placed directly on the unreinforced masonry walls. The building’s lateral system consisted of straight 1x wood roof sheathing which acted as the diaphragm spanning between the exterior concrete and brick unreinforced masonry shear walls to resist lateral loads.

Porches, Stoops, Balconies & Bulkheads

There were no exterior porches, stoops, balconies, or bulkheads. There was an interior balcony.



Within the stage area, there was one concrete stairway leading to a dressing room which was located near the southwest corner and another concrete stairway located near the northwest corner leading to the raised stage. There were two short sets of wood stairs flanking the raised stage.


The interior floors of the auditorium area appeared to have been covered with non-original square vinyl tiles and the stage was covered with wood floor boards replaced in 1966. The entry room had a single row of tiles which formed the baseboards.

Walls & Ceiling Finish

All of the interior walls were covered with painted smooth plaster. The ceiling was covered with painted wood boards.

Decorative Features & Trim

Flanking the proscenium located about mid-height on the west wall were two wrought-iron grilles, which were the only extant decorative features of the stripped, utilitarian auditorium space.


The entry double-doors had wrought-iron push plates. Both doors which flanked the proscenium had wrought-iron straps and a door handle. Some of the simple panel doors appeared to have brass door knobs. The doors appeared to retain their original hinges.