Second prize – large-scale interventions



​By: Jari Lonka, Francesco Allaix & Lilja Mustila

Archigram's Plug-in city was a visionary manifesto of new megastructures on top of the existing city. Their trailblazing approach opened the doors to new way of thinking architecture and urban planning.

Fifty years later the PLUG-IN model is scaled down to the building level in a powerful yet realistic concept. New wooden structures are superimposed to existing buildings. The vertical connections (stairwells and HVAC shafts) are organized as independent new elements, hence the PLUG-IN buildings are fully independent structures, acting as benign parasites to the present city fabric.

The combination of 2 basic modules allows for multiple housing solutions to address contemporary multifaceted needs.

The modular housing units are organized so that one side is fully open towards the exterior (to maximize views, sitting on top of existing buildings), while the opposite side looks towards the inner courtyard or the walkway with shared facilities. 

The basic boxy unit is formed by two prefab CLT bearing walls and two composite walls with MetsäWood LVL elements. The Kerto Ripa floor system is resting on the CLT walls. MetsäWood Kerto T LVL wall studs and plywood are used for interior partition walls.

Communal spaces (such as saunas, workshop room, shared living room, home-office area, etc.) are designed using the same hybrid CLT/LVL system.

The advantages of the hybrid system are that it allows for a fully open façade (unlikely in CLT elements) and uses the CLT and LVL elements at their best. LVL beams to and panels are used in shear walls, such as the façade towards the walkway. Kerto S LVL beams are used to support the glazed façade. CLT prefab elements, on the other hand, are used in load-bearing walls, on which to floor structure sits. Floor slab Kerto Ripa system is the chosen option, being light but sturdy, soundproof and fast in assembly (no on-site concrete casting). 

Four case studies in Helsinki city centre are examined to show the rage of possible combinations.

The Ympyrätalo case study is developed more in detail, since it would be an interesting case study for increasing housing density in a central and lively neighborhood.

The building's location would allow for raising the volume without blocking any close-by building's view and the new apartments would have majestic long views.

Using the PLUG-IN model three independent entryways are set in the arcade in front of the existing office stairwells. In this way the new housing blocks have quick and independent vertical connections (staircases, elevators, new HVAC shafts) that do not alter the existing circulation system and respect the current fire regulations. 

Four new floors are added on top of the existing volume. The existing top floor is a service floor and it would now include both old and new HVAC systems, as a buffering layer between the new and the old structure.

The apartment units and balconies are set on a continuous ring and multiple combinations are design using the prefab modular elements A and B, made out of CLT panels and MetsäWood products.​

The Designers: ​Jari Lonka, Francesco Allaix & Lilja Mustila

Jari Lonka
Partner, L Architects ltd. 
MSc (Arch.) Architect SAFA YKS 508

Jari Lonka is an architect and urbanist living and working in Helsinki. He studied architecture at Helsinki University of Technology and University of Edinburgh. He has also been teaching urban design at Aalto University in Helsinki. Jari has a broad experience in the field of architecture. His work includes  office buildings, hotels, residental buildings and large scale urban plans. Jari  has been awarded in several architectural competitions and for the year 2012 he was granted State Grant for Artists from the Arts Council of Finland.
 Jari is partner and owner of L Architects ltd. ​

Francesco Allaix
MSc (Arch.)

Francesco Allaix has a MSc (Arch). He joined the L Architects in early 2013 and started working as an architect and in the L Architects’ Sustainability Services team. He has experience in urban planning sustainability projects, housing developments and wooden construction. He is a LEED Accredited Professional and has worked with LEED certifications in Finland and in Russia. Francesco Allaix also developed the Green Options tool for L Architects - a tool that is used frequently by the office to estimate the green potential of projects right at the very beginning. 

Lilja Mustila
Student of architecture

My ambition is to create diverse environments for various encounters that include visually and spatially intriguing human scale architecture. Concept-driven design and working with bigger entities are my strengths in architectural process. I like to improve myself in searching new perspectives in both large and more detailed scale of urban life. My interests are flexibility, reuse and ecological solutions in building design and urban structure.

Visualisations in the competition were done by:


Matìas Celayes
3D Artist

Julio Orduña Sánchez
3D Artist


Stefan Winter:

A realistic construction  system for different building typologies.
The more developed solution at Helsinki would be a strong signal for the sustainable development of the city and is convincing form an architectural point of view.

Mike Kane:

This entry was very clear in its adaptable to approach in building in many urban situations and was convincing on many levels.

The winners


Tammelan Kruunu by Lisa Voigtländer (Germany) and SungBok Song (Korea)



Lightweight Living by Joshua Duncan & Chaz Flint​


Plug-In by Jari Lonka, Francesco Allaix & Lilja Mustila


Aboveall by Giuseppe De Marinis Gallo​ & ​​Gianluca Gnisci​​​


The Green Intervention by Minjae Kim &​​ Kwang Ja Oh​


Dear Landlord by Nile Greenberg​


Vertical Lilong by Luis Fco. Romero Martinez & Sandra Gomez Alba​


Colliding Lines and Lives by Sinan Gunay & Nurhayat Oz​​


Dachkiez,Village On The Roof​ by Sigurd Larsen, Simon Jendreizig, Vanessa Panagiotopoulou, Marlene Kjeldsen, Guillermo Fernandez Villar & Pedro Campos Altozano​

City Above the City architecture competition

Plan B : City Above the City architecture competition 

Metsä Wood challenged architects and students around the world to push the boundaries of modern wood building design in the urban environment. Entrants from 40 countries created their Plan B to urbanisation using wood (Kerto® LVL – laminated veneer lumber) as the main material. The task was to design a wooden extension to an existing urban building. The entries were designed to 69 cities worldwide.

Explore the designs