Office Buildings

Illwerke Center Montafon

Vandans, Austria

View from North 1 | View from North
A timber building of the highest degree: One of the largest office buildings in the world made of wood, setting new standards for sustainable building.
Design: In order to create similar conditions for all 270 workspaces, the depth of the building was limited. For this reason, it was extended to a length of 120 meters and, beyond the bank of the lake. The design is centred around the advantages of the modular construction method and the capacities of the local companies. The possibilities of hybrid building were fully exhausted, combining the strengths of wood and solid construction.

Wood: The Illwerke Centre presents the first open market application of the "LifeCycle Tower (LCT)" system. This building system enables timber construction beyond the boundaries of high-rise buildings with a pre-manufactured timber-concrete composite ceiling. The reinforced structure is largely composed of reinforced concrete (substructure, base of the building). The load-bearing facades are composed of double timber supports.

Energy: High-efficiency heat pump technology with a capacity of over 4.5; a fully automatic ventilation system with heat recovery; CO2 metering for volume flow control; automatically regulated blind control; LED lighting with motion sensor and a non-porous building envelope make the Passive House standard. Cold water from a hydroelectric power plant serves as an energy source throughout the year. Users can control light, temperature and glare protection via their PC.

Working Environment 2 | Working Environment
Facade 3 | Facade
Foyer 4 | Foyer
Basic information
Year of Completion |  2013
Investor |  Vorarlberger Illwerke AG, Bregenz (AT)
Architecture |  Hermann Kaufmann + Partner ZT GmbH, Schwarzach (AT)
Structural Engineering |  Merz Kley Partner, Dornbirn (AT)
Construction Time |  6 months (timber construction), 24 months (whole building)
Number of floors |  5 + basement level
Plot size |  161 288 m²
Gross floor area |  11 497 m²
Construction Costs (netto) |  1 718 €/m² (GFA)
Awards |  Staatspreis Architektur und Nachhaltigkeit 2014 (Nomination), Holzbaupreis Vorarlberg 2015 (Prize, hybrid timber buildings), Constructive Alps 2015 (Recognition), materialPREIS 2015 (1. Prize), Hypo Bauherrenpreis 2015 (1. Prize), Europäischer Architekturpreis 2015 Energie + Architektur 2016 (Prize) 
Photography |  Pictures 1-4: Bruno Klomfar, Vienna (AT)

Technical aspects
Concept |  Timber hybrid system (LifeCycle Tower)
Woodworking |  Sohm HolzBautechnik GmbH, Alberschwende (AT)
Origin of Timber, Certification |  2/3 of the timber from Austria (Montafon, Vorarlberg); construction products with various eco-labels (natureplus, IBO certification mark, Austrian Eco-Label, Blue Angel)
Traceability of Timber |  Wood from the region
Forestry Value Chain |  70% of all construction costs contracted out to regional companies
Energy Efficiency Standard |  Passive House, ÖGNI certificate / DGNB Platinum, Klimaaktiv Silver
Energy Systems |  Utilization of waste heat from neighboring hydroelectric power plant, heat pump, controlled ventilation system with heat recovery
Energy Consumption  |  14 kWh/m²a (heating energy demand), < 30 kWh/m²a (primary energy demand)
U-Value Wall | Roof | Floor | Windows (W/(m²K)) |  0,10 | 0,08 | 0,11 (floor), 0,26 | 0,73

Circular Economy Cost Saving

Site Plan Site Plan Floor Plan (Ground Floor) Floor Plan (Ground Floor) Floor Plan (First Floor) Floor Plan (First Floor) Structural Element Perspective Structural Element Perspective