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Sonne, Niederneunforn

Heritage reconstruction with cellulose insulation

Sonne Niederneunforn – heritage building and new addition on a south-facing slope

© Photo: Jan Keller, Pfyn

In October 2019, the residential building “Sonne” in Niederneunforn burned down. Today the heritage-protected building stands again on the same spot – complemented by a new timber-frame addition with a stunning view over the Thur valley.

Fire, restoration, reconstruction

In October 2019, the residential building and its adjoining barn in Niederneunforn were destroyed by fire. After thorough condition assessment, planning and securing works, restoration of the heritage-protected building began around two years later. In mid-February 2022, a new timber-frame structure was erected in place of the barn, in a similar volume. In addition to the two family flats in the existing building, two light-filled senior apartments were created – a striking ensemble of old and new on a south-facing slope.

Sonne Niederneunforn – view of the restored heritage building

Architectural concept

The “Sonne”, gutted by fire in autumn 2019, was restored in line with the requirements of the heritage and energy authorities. Two semi-detached units were inserted into the existing structure, and the original building and roof shape were restored. The new addition was built in a similar volume to its predecessor: the unheated basement in exposed concrete houses services, cellars and parking; above sits a timber structure with a gable roof containing two small semi-detached units.

Sonne Niederneunforn – new timber-frame addition with gable roof

Construction and insulation

Existing building: insulating render on the existing masonry, installation layers, roof and basement ceiling insulated with isofloc cellulose. New addition: prefabricated timber elements insulated with glass wool, roof insulated with isofloc cellulose. Largely untreated timber was used throughout, and great care was taken to ensure a high-performance building envelope.

Sonne Niederneunforn – ensemble of old and new on a south-facing slope

Heritage and townscape

The major challenge was restoring the heritage building, severely damaged by the fire. Working with local craftspeople, the village was able to reclaim this historically significant building – a defining feature of the townscape at the main crossroads.

Sonne Niederneunforn – detail of the timber structure