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Architects: Atelier Kaiser Shen
- Area: 521 m²
- Year: 2023
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Photographs:Brigida González
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Manufacturers: JUNG, Baier GmbH Slidetec, Carl Hansen, Ennogie GmbH, Fensterbau Schneider GmbH, GSL.GLASOLUX GmbH, Herzog & de Meuron, Karcher Design GmbH, Kunststoff-Vertrieb Nuding GmbH, Mawa Design, NUD, Roma, Thonet, Villeroy & Boch, WEM
Text description provided by the architects. Pfaffenhofen is a small village near Heilbronn. It is characterized by an idyllic setting with a church, and half-timbered houses dating from the 16th and 17th centuries in the center of the village, with vineyards rising picturesquely in the background. The village center is now being redensified with a residential building in a cubature typical for the region, which is extraordinary in several respects. For one thing, the way it is built reflects the client’s mindset and area of work. As far as possible the aim was to realize a building that was ideally made from natural and renewable raw materials which can be re-introduced into the natural cycle.
Everything was based on the idea of using bales of straw combined with clay plaster as a thermal envelope for floors, ceilings, roofs, and walls – a practice in use since the late 19th century and that is now making a comeback for a number of reasons: Since straw is renewable and recyclable it is consequently easier on both resources and climate than conventional insulating materials. It is also readily available and can be sourced locally. However, not only is the material itself low-tech, but its handling is also simple: the bales of straw are pressed into a wooden framework to a thickness of 36.5 cm with any excess simply being trimmed off using hedge cutters.
The goal for Haus Hoinka was to realize all six facades – the roof and the floor slab as well – using this straw bale construction method. In order to dispense with elaborate sealing while at the same time still permanently protecting the straw bales in the floor slab from water the house was raised by an entire floor. The compact house rests on a concrete cross and four supports. When the wooden shutters are closed it creates the impression of an elevated wooden monolith which forms a stark contrast to the open garden level. In the process, Haus Hoinka subtly adopts both the grain and roof shape of its setting, and with its staggered structure comprising a stone base and cantilevered wooden building engages in a direct dialog with the half-timbered houses in the center of the village.
The simple basic form conceals a complex nested semi-detached house in which the two residential units are each connected to the garden level via a single flight of stairs. This means that the entrance doors to the apartments are each located on the ground floor. On all floors the residential units are organized by point reflection to one another so that all residents can benefit from the views in all four directions: This means that views from every apartment extend east to the church square, west to the garden, north to the vineyards and south over the roofs of the village into the distance.
On the first floor, the house is divided lengthwise, on the second crosswise. This division is also legible in the interior: For example, the structure of spruce wood and the loam in the apartment facing the center of the village were painted white, while they were left untreated in the one facing the garden. But this division is also subtly visible in the silver fir facade: The widths of the planks in the board and batten cladding vary slightly in the two halves of the house thus giving a hint of the interior.
On the ground floor, the elevation required for structural reasons is achieved by means of a concrete cross and four corner supports. This creates four open spaces that can be used in a variety of ways by the occupants – conceivable options include a charging station for an e-car, a workshop, or an outdoor kitchen. These uses might change over the course of the year: In the summer, for example, the rooms work as outdoor living rooms expanding the indoor living space. The client decided to realize a granny flat in one of these four spaces. Further developments such as a winter garden, a workshop, or a guest room are possible options for the future. Through their choices, the residents will shape the house over the course of the years. The Cite Verticale in Casablanca inspired the architects to adopt an approach that leaves the use of a building in part to its occupants. And indeed, Atelier Shen regards other buildings by the residents of this development as highly enriching.
At Haus Hoinka, emphasis was placed on the use of simple and ecological materials. In addition to the use of straw, clay, and wood, care was taken to ensure that all other materials used also had a good ecological balance and could be recycled and separated appropriately. As far as possible any glued connections that would be difficult to reverse were avoided. All materials including their origin are recorded in a database for sustainable building products developed by the client.
As regards building type, Haus Hoinka demonstrates how residential construction in rural areas can be rethought. A higher density for the village center is achieved through sustainable building construction and using simple materials that can be separately recycled. Moreover, the building offers an extremely flexible floor plan for various constellations of people living together. Not only will Haus Hoinka make future changes possible it will probably also be enriched by them.
