Alvar Aalto Säynätsalo Town Hall Study; Kasey Harrill, Nick Giggenbach,Brynn McClatchy, Lilly Church

To fully understand Alvar Aalto’s butterfly trusses present in the Säynätsalo Town Hall council room, it was decided that hands-on fabrication would be the best way to visualize the structure. The materials chosen for the model include Baltic Birch plywood sheets and Balsa wood sticks. The similar properties and color of these materials allowed one to study the trusses and the surrounding room through the lens of form rather than materiality. After creating four of the walls, three of the walls were attached together. The fourth wall was left unattached to allow views the truss from multiple angles. Because the trusses are notched into the brick wall of the council room, notches were created in the walls to catch the beams and simulate a similar connection in the model. Many of the beams that are structurally significant are not visible because they are embedded in the roof. This led to the decision to remove the roof from the model. Because of this, views of the trusses became visible in areas that would be impossible to witness in the actual Town Hall.

02: Preliminary Research

Research was conducted to determine the size, composition, materiality, and structural properties of the trusses located in Säynätsalo Town Hall. By reviewing line drawings, sketches, models, and diagrams, these unknown elements of the truss system began to reveal themselves. After collecting a large dataset of such information, the construction of the smallscale model trusses began.

The sketches by Alvar Aalto reveal his musings when devising the structure of the butterfly trusses. The hands-on approach to the research project allowed for deeper insight into the thought process of Aalto and his colleagues.

03: Design

The design phase of the project began by analyzing existing drawings to determine the scale and size of the strucutral members that comprise the trusses. From there, a small-scale model made of cardboard and basswood was constructed to demonstrate both the purpose of the butterfly trusses and the viability of the project. The small-scale model and the drawings were used as references to create a CAD document that included precise measurements of the council room itself, which were used to create the largescale model.

The cardboard model pictured here allowed for a demonstration of the butterfly truss system on a smaller scale. Through this model, the method of construction of the large scale model was determined. This model also created opportunities to experiment with lighting conditions and placement for the photograph documentation of the models.

04: Fabrication Process

After the CAD files for the council room were created, they were used to create a set of 1/4” thick plywood guides. The guides were cut using a laser cutter. They were then affixed to the 3/4” thick Baltic Birch plywood sheets and cut out using a router. The corners were cut at a 45-degree angle to allow for seamless joinery at the corners of the council room. Next, the based was crafted from the same Baltic Birch plywood. The model and base were assembled using wood glue. The rightmost wall of the council room was left unglued in order to display the trusses in their full capacity. The trusses were crafted by hand using wooden dowels. Each piece was measured, cut, and sanded to ensure accuracy. The model itself was made at a 1/2” - 1’ - 0” scale.

The construction process necessitated hours of work both in and out of the wood shop. The creation of the model was an opportunity to learn new skills and consider unique methods of model construction.

The assembly process required a few innovative solutions. Three exterior walls were glued together and held with a corner clamp. They were then spaced apart by the central beams of the trusses. After notching the interior of the walls to receive the beams, they were put into place . The struts were then added to complete the truss.

05: Model Photographs + Findings

The trusses in Säynätsalo Town Hall are able to support the roof structure through the angled struts that fan out from either side of the central beams. This eliminates the need for heavy timber beams within the roof and allows for improved ventilation between the interior and exterior surfaces of the roof. The exclusion of the roof itself in the model allows one to view the trusses in a way that would be impossible in their current state. By allowing the trusses to catch the sunlight and cast shadows on the council room floor, the model is able to capture what Säynätsalo Town Hall might have looked like for a brief moment under construction.

The light shining through the beams of the trusses is a view not seen in the Town Hall itself. However, during construction, this view might have been possible before the roof structure was completed.

06: References

Aalto, Alvar, Juhani Pallasmaa, Alvar Aalto Foundation, and Alvar Aalto Academy. 2003. Alvar Aalto, Architect. Helsinki: Alvar Aalto Foundation.

Gutheim, Frederick Albert. 1960. Alvar Aalto. The Masters of World Architecture Series. New York: G. Braziller.

Weston, Richard. 1993. Town Hall, Säynätsalo: Alvar Aalto. Architecture in Detail. London England: Phaidon Press Limited.

07: Figures

FIG 1 - (PAGE 124) - McCarter, Robert, and Alvar Aalto. 2014. Aalto. London: Phaidon Press.

FIG 2 - (PAGE 33), FIG 5 - (PAGE 45) - Weston, Richard. 1993. Town Hall, Säynätsalo : Alvar Aalto. Architecture in Detail. London England: Phaidon Press Limited.

FIG 3 & 4 - “Säynätsalo Town Hall - Alvar Aalto Foun dation: Alvar Aalto -Säätiö.” Alvar Aalto Foundation Alvar Aalto -säätiö, June 14, 2022. https://www.al varaalto.fi/en/architecture/saynatsalo-town-hall/

FIG. 6, 7, & 8 - Aalto, Alvar. 1949-1952. Saynatsalo Town Hall. https://library-artstor-org.ezproxy.lib. vt.edu/asset/AWSS35953_35953_29398280