In Brandenburg, Germany, Peter Grundmann Architekten has completed Haus Giebel, the conversion of an old settler’s house into an open, multi-layered family home. The modest dwelling belongs to the early 20th-century tradition of German Siedlerhäuser — simple, elongated houses built for working families and often extended over time.

Form and openings

Originally built around 1900 and extended several times until the 1990s, the house grew from an initial length of 9 metres to almost 25 metres, while its width remained fixed at 7.5 metres. This expansion produced a gross floor area of 186 square metres. The substantial wall thickness meant the existing volume already satisfied the needs of the three-person family, avoiding the need for annexes or additions.

With its elongated, narrow form, the building offered strong potential to reimagine the original low, compartmentalised rooms. Over time it had also accumulated a variety of wall openings, ranging from small 40 × 40 centimetre apertures to the scale of a garage door, reflecting its earlier use as living space, storage, workshop, and garage.

In response, Peter Grundmann Architekten chose not to cut new openings in the long facades, instead preserving the irregular geometry of those already present. Some were closed with frameless glazing, others with framed windows, while one wall opening was fitted with a sliding door that opens to its full width.

Interior organisation

At the street side, the oldest part of the house contains two preserved rooms, now serving as a bedroom and guest room. The original entrance was retained and opens into a cloakroom and bathroom enclosed with translucent glass, which diffuses daylight and artificial light into the hall.

Beyond this point, the ground floor expands into the kitchen and the play, dining, music, and living areas. All interior walls and even the floor slab were removed here to create a continuous, flexible space. To brace the house without partitions, four slanted timber frames were connected to the existing roof. Most of the roof beams and all of the clay tiles were preserved, giving the new openness a visible link to the building’s history.

An interior staircase then leads to the attic. On the street-facing side are the parents’ bedroom, a room for their daughter, a WC, and a study. The parents’ bedroom features a large square opening in the gable, a clear architectural sign of the transformation. The bathroom, WC, kitchen, and study are enclosed with frosted glass partitions. Above the entrance to the parents’ bedroom, the triangular space between rafters and ridge is infilled with transparent glass, ensuring acoustic separation from the gallery while preserving the sense of continuity within the open volume.

Towards the garden, the attic opens into a sequence of galleries, voids, and an indoor terrace. Activities such as sleeping, playing, and making music take place here. A nearly 10-metre-long catwalk connects the attic spaces, bridging the large volume and offering new perspectives on everyday life. At the garden gable, a glazed facade leads to an outdoor terrace with steps descending into the garden.

Design philosophy

“Context is our main focus — even the smallest trace is valued, because the connection between the existing fabric and the new intervention elevates the architecture to a higher level of complexity,” says Peter Grundmann. “The narrative of the new building reaches back to the year of the original structure through the reuse of material, and from there it extends forward into the future. Context also includes nature and the landscape, which should retain their original state even when new architecture is added. In this way, both nature and architecture preserve their independence. Neither dominates; instead, a dialogue emerges between them on equal terms. In other words, sustainability in our work has been the outcome, even though we began with different goals.”

Structure and materials

The house is heated by an air-source heat pump, visibly placed at the street gable, which distributes warmth through underfloor heating. Materials reinforce the character of the conversion: exposed screed on the ground floor, pine plywood panels on the upper level, also used for sloping ceilings and walls, clay plaster applied to the interior of the old brick walls, and lime plaster partly used on the exterior. The thickness of the original walls meant that no additional insulation was required, while the use of natural, simple materials and the preservation of much of the existing structure kept the environmental impact low.