Toblerone By Daniel Oberthaler & Lukas Walchhofer


​By Daniel Oberthaler & Lukas Walchhofer

As the mission of this challenge was to choose an existing building in a populous city where an extension for residential purposes is possible, we soon thought of the „Flatiron-Building “. With its 21 floors it’s still not the highest building in the city of New York, which is why we think an extension would definitely make sense in terms of housing and would overall be possible. 

The concept is based on a parasite's architectural concept. The extension differs in all essential parts, as of the construction and material, apart from the triangular ground plot. Five flats are situated in every floor, which differ in their size as well as according to requirements. 

In tribute of the trend-setting steel frame construction the Flatiron-Building is made of, we decided to pursue the building’s main raster in our wooden construction, which offers a range of five to six meters that is adaptable for wooden constructions. Thanks to „Kerto“, a wooden girder, incredibly thin panel thicknesses are possible within these constructions. Inspired by the building’s triangular base form our concept’s main construction exists of triangular hollow-cross-sections made of „Kerto-Q“-panels. Therefore, the laminated veneer lumber is separated in strips and put in triangular-cross-sections due to an accordingly adapted edge form. A major advantage of this concept is the stiffness of the individual rods. Because of the extreme components heights, rigid corners are possible. This enables the construction of storey-frames, which makes additional stiffening in the area of the frames obsolete. Elevator shafts made of „Kerto-Q“ and the crosses formed by the frames ensure stability in the transverse direction. In between the main structure „Kerto-Ripa“-elements are used to build parts of the roof and the ceilings.

On the outside, an open, transparent and nearly see-through skin of glass that wraps the rough wooden construction, generates every floor's exposure. Shadows and blinds are formed by movable translucent glass walls. These shear walls offer the possibility to build variable ground-plan area. The triangular formed shoring stays visible and have impact on the open room plans and the arrangement of walls of each flat. Furthermore, the shoring's triangular form includes the recurrent forms of the floor plan. With this concept we show how to generate living space in a tight covered metropolitan area with hardly any free building area. The three upper storeys are created for housing and the ground floor inhabits technique as well as indoor (glasshouse) and outdoor areas for gardening and every other type of public needs for all people living and working in the building. The idea was to create something like green lungs for the existing building and its extension also thinking about the plants as carbon sinks in downtown Manhattan.

At the end, our concept shows the possibilities of wood constructions on statically outbid buildings – and in this case, the Flatiron-Building in the city of New York.​

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