Boltshauser Architects converted a school in Allenmoos, Switzerland into an afterschool centre using natural materials.

Designed as an afterschool facility for children aged 4–13, the new building incorporated the basement and a few concrete walls from the original pavilion. The result is a structure that greatly resembles the original modernist building, but is used in a different and empathetic way. The facility has five south-facing rooms with a connecting corridor along the back. The flat roof is fitted with skylight boxes, while stairs down to the basement, toilets and a kitchen have been added to the north-west. In the west gable, the main office’s large window directly echoes the front door, which is the only opening in the opposite east-facing gable.

The loggia that connects the building to the park is a remarkable feature that feels protective from the inside and conveys permeability and transparency from the outside. The rear façade, which runs along a public path, seems far more compact and protective, but doesn’t completely forego spatial depth. On either side of two large windows are narrow but deep niches that enable the ventilation hatches embedded in the windowsills to open outwards.

As one approaches the pavilion via the path in the park, the rust-red clinker cladding asserts itself, emerging with a rustic and warm appearance markedly different from the surrounding light-plastered façades so typical of Swiss suburbia. Bolthauser advocated a brick façade in hard-fired Kolumba, similar to the one used in 2010 for the facing wall in the backyard of their Zurich studio.

However, the authorities decreed that the energy used to produce the materials for the pavilion be kept to a minimum, which precluded the thickness of the original brick (110mm). Bolthauser asked Petersen TEGL to produce a façade clinker that was only 2cm thick, 11cm high and 53cm long. The clinker is fixed directly onto the underlying 250mm insulation, and is pointed with a cement mortar compressed to a couple of millimetres. To make sure that the façade was durable, the studio built a 1:1 mock-up that coped admirably with all kinds of weather and wind.

The expansion joints are gently inserted into the outward-and inward-facing corners but deliberately avoided in the middle of the long, north-facing façade and above the corners of windows. The Kolumba clinker is handmade and not completely flat, which endows the façade with a very welcoming character, avoiding the clinical, bathroom-like feel of many façades clad with tiles or facing bricks. The horizontal format of the clinkers emphasises the body of the building’s resting Gestalt, but the vertical joints also dispel any association with a massive wall.
The same brick tiles are inlaid on the surface of the loggia’s clay columns as protection against erosion, and have a tectonic, ornamental look that evokes associations with geological striations. The distance between the 12 horizontal delineations increases as they ascend the column. The columns appear solid and sturdy, but on closer inspection their load-bearing capacity seems ambiguous. The loggia’s elegant concrete roof appears to be wedged in between the columns, although it is actually mounted on top of them.

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