Architekturobjekte

Heinze ArchitekturAWARD 2026: Teilnehmer

TOP-UP LEITZ - reframing a former vertical factory

Diese Objektpräsentation wurde angelegt von: Universität Stuttgart, Architektur und Stadtplanung, Matthias Eberle

flexible living - buffer zone - TOP-UP LEITZ - reframing a former vertical factory

Leitz-Areal - TOP-UP LEITZ - reframing a former vertical factory

top-up Leitz - TOP-UP LEITZ - reframing a former vertical factory

Leitz-Areal - existing condition - TOP-UP LEITZ - reframing a former vertical factory

Leitz-Etagenfabrik - existing condition - TOP-UP LEITZ - reframing a former vertical factory

Diese Objektpräsentation wurde angelegt von: Universität Stuttgart, Architektur und Stadtplanung, Matthias Eberle

Basisdaten zum Objekt

Lage des Objektes

Deutschland

Objektkategorie

Wohnungsbauten

Objektart

Sonstige Wohnungsbauten

Art der Baumaßnahme

Entwurfskonzept

Fertigstellungstermin

02.2026

Zeichnungen und Unterlagen

annual daylight analysis before intervention

daylight intervention

daylight before and after intervention

structural transformation

second skin: summer

second skin: winter

standard floor: flexible modules + infrastructure

standard floor: convertible setup

isometric-view: flexible floor plans

potential of the existing building

cross section with extension

section with extension

groundfloor

social mezzanine

energy generation and storage

Gebäudedaten

Bauweise

Holzskelettbau

Tragwerkskonstruktion

Holz

Anzahl der Vollgeschosse

11- bis 20-geschossig

Raummaße und Flächen

Bruttogrundfläche

39.920 m²

Nutzfläche

32.400 m²

Verkehrsfläche

6.300 m²

Wohnfläche

25.600 m²

Beschreibung

Objektbeschreibung

The project is located on the Leitz-Areal in Stuttgart, where the former multi-storey factory ("Etagenfabrik") forms the largest and most defining structure of the site. Built between 1966 and 1969 by architects Georg Heinrichs and Hans Christian Müller, and later extended in 1990 by Schwarz Architekten, the reinforced-concrete building embodies the logic of a single-floor factory: large, flexible halls organized within a clear structural grid and served by powerful vertical circulation cores. Today the listed building is characterized by significant renovation needs, including an uninsulated façade, outdated building services, and asbestos-containing screed, all of which complicate any transformation. At the same time, its robust structure and generous floor plates represent an extraordinary spatial resource.

The central challenge of the conversion was the building depth of 24 m, which is typically unsuitable for residential use due to insufficient daylight penetration. A key design principle was therefore to enable housing while preserving the building's inherent flexibility. Interventions such as cutting large atria or voids into the slabs were deliberately avoided to maintain the possibility of future uses requiring large contiguous floor areas. To bring daylight deep into the plan, the proposal introduces a layered reflection system. Large mirrors mounted on the façade capture incoming sunlight and redirect it toward a glass-block wall, where the light is diffused. Inside the apartments, highly reflective aluminium ceiling panels and a polished screed surface further distribute the light across the depth of the space.
A further challenge was the energetic refurbishment of the envelope. This is addressed by introducing a continuous buffer zone in the form of an external access gallery, effectively creating a second thermal layer. The new façade system improves insulation while allowing the historic structure to remain largely untouched. The existing industrial screed, which contains asbestos, is encapsulated with a thin new sealing layer of polished screed. The original windows are in poor condition and unsuitable for residential standards. Their characteristic fibrous glazing diffuses light strongly and prevents visual clarity, making replacement with a new glazing system necessary.

All building services are distributed from the vertical circulation cores, which house generous service shafts. From there, the installations run as bundled packages into each structural bay, with each package comprising an electrical cable tray, supply and return water lines, and the flow and return pipes of the central heating system.

Beschreibung der Besonderheiten

The highly flexible floor plans allow residents to add or remove rooms from their unit, enabling a remarkable range of configurations — from large cluster apartments and shared living arrangements to single-room dwellings. Moveable bathroom and kitchen units can be freely positioned throughout the space, connected via fixed, openly installed service runs beneath the ceiling that provide connection points in every bay. These units function simultaneously as spatial zoning elements, dividing and organizing the open floor plate without fixed partitions. This flexibility also allows for an extreme degree of individual customization, as well as a mode of living that responds to the seasons — for example, shifting the living area toward the façade in winter to benefit from solar gain, and retreating to a cooler position deeper in the plan during summer. Each bathroom and kitchen unit is equipped with a macerator pump to convey wastewater upward to ceiling level, from which point the drainage runs with a continuous fall toward the cores. The use of macerator pumps also allows for a significant reduction in the cross-section of the drainage pipes.

Nachhaltigkeit

Energy for the building is generated through photovoltaic panels on the façades and roof of the vertical extension, supplemented by four wind turbines positioned at the building's cores. The energy produced is stored in one of the towers, which functions as a gravity energy storage system — lifting and lowering heavy masses to store and release electricity as needed. Hot water is stored in a second tower and heated through solar thermal gain: the building's guardrail elements along the external access gallery serve as solar collectors, circulating cold water through their exposed surfaces, where it is gradually heated before being fed into the storage system.
Beyond energy systems, the building's greatest potential lies in its structural capacity. Designed for industrial loads of approximately 20 kN/m² per floor, the conversion to housing requires less than 5 kN/m², freeing substantial reserve capacity. This allows an 11-storey timber vertical extension, increasing the overall height to 18 storeys and enabling accommodation for roughly 800 residents. Reusing the existing structure avoids the need for new foundations, which for a comparable new building would generate around 576,000 kg of CO₂ — an amount that would require approximately 7 hectares of forest growing for 80 years to offset.

Schlagworte

Umbau, Bestand, Etagenfabrik, Leitz-Areal, Stuttgart-Feuerbach, Wohnungsbau, Nutzungsänderung, Flexibilität, Grundriss, Tageslicht, Spiegelsystem, Tiefes Gebäude, Pufferzone, Laubengangerschließung, Thermische Hülle, Asbest, Clusterwohnen, Aufstockung, Holzbau, Tragwerksreserve, Photovoltaik, Windturbinen, Hubspeicher, Solarthermie, CO2-Einsparung, Wiederverwendung, Saisonales Wohnen

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TOP-UP LEITZ - reframing a former vertical factory

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