Project Description

Leutschenbach School (Schulhaus Leutschenbach) is located in the north of Zurich. Designed by architect Christian Kerez, aimed to offer a completely new dimension for learning, this building has brought all the function zones under one roof and one next to another: classrooms, meeting rooms, the cafeteria, the music room and even the gym hall. To highlight the architectural creation, the gym hall is designed to be on the top floor instead of submerged under the earth.

The entire classroom part of the school building is added to the framework of the fourth story and forms a more than 10-meter roof which projects over the playground. The static of the building is provided by a steel structure and an embedded slab which is supported on only six points. These compose of the foundation for the large gym hall and ensure the building to be completely earthquakes resistant.

Sika Solutions

Recycled Concrete for the Basement Waterproofing:
The bad ground condition required a pile foundation to bear the immense load of the steel structure in the building and an elaborate early-planned solution for basement waterproofing.

The precondition was set to use ecological materials, therefore recycled concrete was a must. The recycled concrete also has to be watertight to protect the basement against the ground water. Sika® Permaton is the right solution to fulfil these requirements, and the recycled concrete contains over 50% recycled concrete granulates.

In addition, Sika® ViscoCrete® superplasticizer further ensured excellent workability of the cement and reinforced the watertight feature for the required water exposure classification of the concrete basement structure. Permaton and Sika have rich experiences with the Permaton “White Box” system using recycled concrete in many buildings in the city of Zurich. These experiences also guaranteed a perfectly watertight structure in this school building. A ten-year warranty was given to this case.

Ecological and Economical Fire Protection with Sika® Pyroplast:
The facade which is composed of steel structures needed to be protected against fire and reach the fire resistance of R30 and R60. After the evaluation carried out among planners, Steel frame constructor and owner, Sika® Pyroplast was chosen to be the right fire protection system for the facade. About 1,100 tonnes fire protection material were applied to the load-bearing steel framework, covering altogether five floors including the structures inside and outside the building.

The Sika® Pyroplast system is proved to not only be extremely economical, with excellent quality and weather resistance, but also met the expected environmental requirements. A total of 3,500 m2 was coated. The corporation between Sika and the SCE Consulting has guaranteed the quality assurance for this very challenging fire protection task.

Solar Roof with Sika Sarnafil® Membrane:
The solar power business of power stations in Zurich has made the solar roof at the top of the Leutschenbach School building possible. Sika Sarnafil provided solar roof solution for it. On the finished roof, solar photovoltaic modules were integrated and installed as the second layer. The solar modules were welded to the Sarnafil® roofing membranes below.

Sika Products

In addition the following Sika products were used in the project

  • Sika® Waterbar Forte plus
  • Sika® ViscoCrete®
  • SikaCor® EG Phosphat
  • Sika® Pyroplast ST 100/Steel LH
  • Sika® Pyroplast PU Top
  • Sarnafil® S 327 – 18 EL

Check out more information about Sika construction products in the Swiss market

Project Participants

Owner: Amt für Hochbauten der Stadt Zürich
Architect: Christian Kerez, Zürich

- Dr. Schwartz Consulting AG, Zug

- Dsp Ingenieure und Planer, Greifensee

Construction management: BGS Architekten GmbH, Rapperswil
Contractor: Barizzi AG, Bertschikon
Basement waterproofing with guarantee: Permaton wpc, Winterthur
FlFlat roof: Sada, Zürich
Solar professional: Zagsolar, Kriens
Steel construction: Zwahlen+Mayr SA, Glattbrugg
Fire protection application: Taufer AG, Klus