An Unassuming Addition – CLT Passive House by betti&knut architecture

Extending an existing 1920s Californian bungalow home, CLT Passive House inserts itself as a sensitive and considered addition. betti&knut architecture proposes a self-sustaining structure that epitomises efficiency in both its timely construction and its energy load over time.

Instead of adding onto the existing structure, CLT Passive House sits as its own contained entity, utilising a large portion to the rear of an existing allotment in Balgowlah. As one of only 30 Passivhaus certified homes in Australia, the CLT technology behind its namesake ensures optimal airtightness, sustainable performance and significantly reduced construction time on site. Originally developed in Europe, the technology ensures each panel is prefabricated with service cut-outs and insulation already integrated, transferring to less time and trades on site. betti&knut architecture combines the structural system with a deliberate casing of locally sourced timber panels to allow the building to grey and patina over time, becoming one with the surrounding landscape.

betti&knut architecture combines the structural system with a deliberate casing of locally sourced timber panels to allow the building to grey and patina over time, becoming one with the surrounding landscape.

The decision to build a separate structure was born from an experimental curiosity with the CLT system, as well as ensuring that the form created would take on some of the landscape’s character. It was also imperative to allow an immersion within the garden, where the separation also allows for a natural delineation of areas for the family and their needs. The overall form was designed around existing trees in order to preserve them; as a key observation of the area and a lack of these trees in other properties, it formed a key part of the brief. By choosing a natural material to wrap the structure, the home organically blends within its context. Internally, a softer yet still texturally warm finish is expressed through exposed panels.

On the lower level, a living, dining and kitchen space opens up to a number of terraces, encouraging a conversation with the garden. The quieter and more retreat-type areas are then placed upstairs, where a mezzanine accommodates a dedicated study. Removing the need to finish and fix an additional surface to the interior avoids time on site while also reinforcing a connection and consistent materiality throughout. In reducing a reliance on trades, and in the lessening of offcuts by prefabricating elements, the technology allows for impressive efficiencies. Whilst the panels for CLT Passive House were fabricated in Austria by KLH, once on site, it took approximately one week to seal the structure.

Removing the need to finish and fix an additional surface to the interior avoids time on site while also reinforcing a connection and consistent materiality throughout.

Focusing on healthy and sustainable living, CLT Passive House is a welcomed addition to the family home. betti&knut architecture elevates the quality of the everyday whilst establishing an individual sanctuary amongst the trees.