Throughout his career, one of Schindler’s main interests was shaping interior space. He did this not just in plan (the size and arrangement of rooms), but most importantly in the vertical dimension. His spaces have different heights, sloped and flat ceilings, and lots of glass that opens to views and light. Frustrated with the cost and limits of standard construction, the construction system he used on his earlier Plaster Skin designs, he developed the Schindler Frame to allow him the greatest flexibility in shaping spaces. 1
“…giving the space architect complete freedom to shape rooms.” 2
Schindler used clerestory windows in the Plaster Skin design McAlmon House and Apartment (figs 1 & 2). However, the clerestories are limited by the thickness of the standard roof/ceiling construction. There is only one clerestory in the House, in the secondary bedroom where it lets in northern light. Clerestories are a major feature at the front of the Apartment, but require a high ceiling (9’-4”) to make room above the folded plane. In both cases they occur at walls, not at ceiling changes in the middle of rooms.
To understand what makes the Schindler Frame different from standard construction, I will compare two cross sections. Figure 3 shows a cross section of the Schindler Frame prototype. Figure 4 shows a similar cross section built as an earlier Plaster Skin design (the Plaster Skin houses used the standard western platform framing). This will allow me to compare two similar spaces built in two different systems.
“The “Schindler Frame” eliminates all rafters in favor of tongued and grooved plank flooring, which forms roof and ceiling at the same time.” 2
The Plaster Skin roof/ceiling/structure (figure 4) is more complicated, with many pieces: roof sheathing, 2x rafters at 16” on center, 2x “wedges” to create roof slope for drainage, and a plaster ceiling. This makes a roof that is thicker, approximately 12”.
Simpler roof drainage
“Since the composition roof used may spill at all edges, roof slopes may be eliminated completely or reduced to a minimum to help drainage.” 2
The Schindler Frame roof (fig5) is flat or slightly sloped. Water rolls off the roof at the eaves, through a space between the sheathing and the fascia (fig 7). Roof slope might add +- 2” thickness to the roof height.
The Plaster Skin drainage (fig 6) is more complicated, again with more pieces. The roof slopes towards the center, where a roof drain connects to a pipe that runs through a wall. The roof slope and parapets add about 16” to the roof height.
Overall Roof Thickness
Schindler Frame 2” to 4”
Plaster Skin +-2’ -6”
Lower building height
“The standard roof construction with rafters, sheathing, ceiling joists, and plaster, is complicated and so thick that clerestory windows between roof levels necessitate excessive ceiling heights.” 2
Because the Schindler Frame roof (fig 5) is so much thinner than the Plaster Skin roof (fig 6), the height required for a stepped roof with a clerestory window in between is much lower. This allows a much lower overall building height.
Overall Building Height
Schindler Frame +-9’-0”
Plaster Skin +-11’-6”
One stud height
“…cutting all studs throughout the house to door height, and thus provides a continuous belt of plates at this height.” 2
Wood framed walls have horizontal pieces at the top to tie the vertical wall pieces (studs) together, and to transmit horizontal forces (wind and earthquake) to the wall and throughout the house. These horizontal pieces are called top plates. Western platform framing typically has two 2×4’s laid flat as top plates. The roof structure sits on top of the top plates.
The Plaster Skin section in figure 6 shows these double top plates, shaded in yellow. Note that where the ceiling steps, the upper and lower plates do not connect. Special detailing is required to transfer the structural forces between the plates at different heights.
A key difference in the Schindler Frame is that the top plates are all at the same height (figure 5, shaded in yellow).3 The roof/ceiling structure does not rest directly on the top plates. Instead it sits on the clerestory framing. The clerestory framing raises the roof/ceiling to its final height.
Since the plates do not step up at high ceilings, there is no need for the complicated detailing required at the Plaster Frame plate and ceiling steps
Note that, in the Schindler Frame, only the upper top plate (dark yellow) is continuous around the building.4 The lower top plate (pale yellow) is cut out at doors and windows.
Simpler changes in ceiling height
Because the Plaster Skin roof sits directly on the walls, when the ceiling steps up, the walls supporting it have to be built taller (fig 6). In addition to the structural detailing mentioned above, this requires that the location and height of each ceiling step need to be established at the time the wall construction starts. The design has to be well defined and drawn before construction starts. Ceiling/roof revisions require rebuilding walls.
The top plates in the Schindler Frame, however, are all at the same height. Changes in ceiling height are created by the clerestory framing, which consists of 2x’s of different height standing on top of the plates. Ceiling heights can be easily visualized by putting up the clerestory framing, changes can be easily made after the walls are all built (fig 8).
“Just draw anything in. I’ll work them out when we start building” Schindler to Ester McCoy 5
Cheaper window construction
The Plaster Skin houses have large, non-typical and expensive steel windows.
The Schindler Frame houses have common (at that time), cheaper wood windows.
Plate organizes window design
Plaster Skin windows are often full height, going up to the ceiling without interruption.
Schindler Frame windows are placed either above or below the single top plate, which runs through the house uninterrupted.
So, what Difference do these Differences Make?
“Schindler did not approach a minimum house from the point of view of how much he could leave out; he exercised the strictest economy on structure so he could indulge in what he considered the vital luxuries of life.”6
The common threads running through the Schindler Frame differences are simplicity of construction, reduced cost and increased design flexibility (fig 9). In providing this, Schindler Frame buildings look different. Most significantly, the thin roofs with projecting eaves are very different from the thick, flat parapets of the Plaster Skin houses. The Schindler Frame eaves and sloped roofs don’t look like the widely accepted image of modern architecture. Sometimes they resemble generic builder houses, but mostly they don’t resemble anything else at all. Schindler’s interest and emphasis moved from sculptural exteriors to focus on dynamic, complex interior spaces. He developed a system to design and build them. He accepted and worked with the “different” exteriors that resulted from that system.
“Schindler’s last style in which the roof emerges as a prominent design feature comes out of World War II material shortages and the hourly wage of plasters.” 7
9 Schindler Frame cross-section with quotes from Schindler Frame article
7 Ester McCoy, “Schindler at Work: An Appreciation” inRM Schindler: Composition and Construction, eds. Lionel March and Judith Scheine (London: Ernst & Sohn, 1993) pg 261.