AZH Training Center, Buchs/

Initial situation 

The timber construction industry has changed significantly in recent years. Prefabricated construction requires  apprentice carpenters to have specialized knowledge that could no longer be adequately covered by previous  apprenticeships. The scope of introductory courses, which are intended to shape the learners’ technical skills in  addition to vocational school and practical work in the company, has also been increased. In order to complete  these courses, a new training center was built in Buchs, canton Zurich (Switzerland). The new building, which  emerged from a project competition, is a big step for the industry and was possible to be constructed thanks to  the division into construction stages and a clever “public-private implementation model”.

Idea 

The character-defining element of the training center is its supporting structure; the fine pillar and beam  structure basically produces the architecture, referencing a proud and sophisticated tradition of wood  construction. Twin supports interconnect with the load-bearing ceiling beams and the widely overhanging roof. The repetition of this supporting structure results in a profiled façade, whose projections and recesses create a  striking play of shadows. Framed windows with vertical ventilation sashes fill in the verticalized façade, whereas  the strong roof provides a clear horizontal finish.

The relatively flat two-story building thus strikes a subtle balance between a vertical-looking façade and a  horizontal presence overall.

Urban planning concept 

The new building is located in the commercial zone of the municipality of Buchs ZH. Together with the  neighboring buildings, the new building fits into the existing neighborhood structure and strengthens the outdoor  spaces. The volumetrics, which were originally built in a square shape, were during the competition already considered as an expandable structure. Starting from the corner of the property, the bulkhead-like building grew  by additional three axes towards the north shortly after the completion of the first stage.

Architectural implementation 

The house is very transparent and allows for complex visual relationships. Based on the urban development  setting, the workshop rooms occupy the well-lit east and west sides. The engine rooms are positioned between  them, easily accessible from all sides, and form a kind of central nave. You get lots of natural light from the  south. This central nave extends with the access core up to the upper floor. The core has three floors and includes all wet rooms, cloakrooms, riser zones and technical rooms as well as the main staircase with the lift. The school floor functions as an actual learning world with a wide variety of switching options: the classrooms  can be connected to each other. The reserve areas are open and can be used multifunctionally, for example as  individual learning areas for group work or as a seminar zone. The natural lighting makes this ante-zone an  attractive additional room.

Construction 

The three-aisled facility is also reflected in the supporting structure: the base plate, together with the north-side  core, forms a stiffening concrete stage. Slim, plated wooden frames with beams and twin pillars are placed on  this base. With statically sensible span widths, the construction can be divided into large spans of the cross  beams and small spans of the field ceilings. The wooden ceiling above the ground floor was designed as a  wood-concrete composite ceiling. This solves noise and fire protection. The bracing takes place via the  concrete core and the wooden gable walls. The modular structure could be easily continued in the case of the  north-facing extension.

The structure consists of simple static components: the roof consists of three-layer panels and beams, the  ceilings of over-concrete, three-layer panels and beams; there are no paneling or suspended ceilings. The  cross sections are deliberately chosen to be slim and high. The delicate supporting structure thus forms a certain degree of sun protection on the east and west sides, similar to a brise-soleil. Filigree blinds, which run in  front of the wooden element windows, serve as sun protection elements. They allow for individual shading of  the usable spaces behind them and react with the horizontal pull direction to the partial shading that already exists due to the deep supports. The large canopy proves to be a key element for such an external support  structure. Even on the west side, the wood is practically not weathered. The facade was treated with pre greying glaze, which means there are almost no renovation intervals. For double safety, the beam heads  running outwards were also covered with a wear cap. This ensures that any weathering does not directly affect  the supporting beam. The external connections are also designed so that there are as few contact points as  possible and sufficient air circulation ensures drying.

A permanently sealed building envelope requires dimensionally stable, penetrating components. These components are exposed to various climatic conditions indoors and outdoors, which work to alter the wood  profile through shrinkage and swelling. Transverse reinforcements of the wood beams at the juncture between  inside and outside prevent this.

Inside, the simple choice of materials continues: “raw” exposed wood surfaces (untreated / UV glaze), exposed  concrete core in classic board formwork (Type III) as well as a wooden floor on the classroom floor and a robust  mono-concrete floor in the workshop.

The modern timber construction symbolically represents the contemporary carpentry training.

Sustainability, energy, home technology concept

The system is structurally, constructively and technically optimized for low environmental impact and a long  service life. With spacious rooms and lots of light, users are positively influenced. The overall building envelope  aims to have a glass content of around 60%, which makes sense in summer and winter. The north-facing  facades have no openings for energy reasons. In winter, when the sun is low, the solar gains occur through the  generously opened facades. The windows have triple glazing and night cooling ventilation sashes behind the  blinds. The requirements of the Minergie standard are met. Thanks to timber construction, constructive thermal  bridges are minimized, and continuous beams are also no problem. The heat is supplied via a long-distance  pipeline; the heat is generated via a wood heater with a fine dust filter. The electrical and IT connections take  place along the facade via floor channels. With the generous canopy, structural timbers and windows are well  protected from the weather and are therefore long-lasting and low-maintenance. The embodied energy is  optimized with a minimal construction volume underground and a simple wood and concrete structure.

Outdoor space 

The existing row of trees provides the forecourt with a welcome shade roof and an adequate counterpart to the  delicate facade. The different tree species also serve as a “sample collection” for training purposes. A change of  surface from asphalt to gravel strengthens the forecourt. On the north side, a newly created poor meadow will  create a certain replacement for the previously existing green space. The newly routed delivery route in the very  north of the plot creates a connection to the Hartwag wood warehouse and is also used to deliver the new  building on the east side. The paths around the new building are generally designed to be one-way, so that both  the forecourt and the delivery area on the south side have an exit. The existing birch trees on the south side will  be retained and will integrate the new building into the established structure right from the start.

Client: Ermitin AG

Specialist planner:

• Timber construction engineer: Makiol & Wiederkehr,
• Civil engineer: SIPAG Seiler Bauingenieur + Planer AG,
• Building physics: Raumanzug GmbH,
• Heating/Ventilation engineer: Schär + Egli GmbH Ingenieurbüro HLK,
• Plumbing engineer: Keller Haustechnikplaner Sanitär GmbH,
• Electrical engineer: Elektro Compagnoni,
• Construction management: Andreas Seiz.

Photographs: Roger Frei.