Passive Butterfly

Armadale 2017

How do you turn a south facing extension into a passive house? Respectfully placed behind the existing heritage home to the north the solution was a sculptural butterfly roof soaring northwards. Highlight windows wash the living room rammed earth wall, a heat sink on cold winters days. Attention to detail has been of premium importance on this project as the client is targetting Passivhaus standards of airtightness and thermal integrity. There must be no chinks in the armour!

Sustainability Awards 2018 winner – Best of the Best

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  • Best of the Best – Sustainability Awards 2018

  • Single Dwelling Alteration or Addition –¬†Sustainability Awards 2018

  • Best Environmentally Sustainable Design – Residential [Commendation] – BDAV 2018

  • Best Sustainable Design – NABD 2018


This project includes:

  • Internal rammed earth thermal mass wall

  • PV panels

  • Heat recovery system

  • Super insulation, including upgrade to the existing building

  • Stringent attention to preventing thermal bridging.

passive house rammed earth


Size: Site 435m2, Existing building 150m2, Proposed building 170m2 & shed 25m2, Garden/Outdoor Entertaining 241m2

Challenges: South facing block, heritage overlay, bulky adjoining properties, sloping block, targetting Passivhaus standard

Building Star Rating: 7.6

Features: 3 bed, 2 bath, open plan living, lounge/home office, two courtyards for outdoor living, rammed earth wall, morphed butterfly roof



passive house passiv haus rammed earth

Sustainable Strategy

Hot water: sanden energy efficient hot water heat pump

Water Saving: 2 x 5,000 L underground water tanks, grey water divesion to garden

Renewable Energy: Solar PV system

Passive Design: Morphed butterfly roof provides high-level shaded north facing windows to bring light into south facing extension, minimised east/west glazing, airlock between existing and proposed, operable windows located for cross ventilation, high thermal mass in rammed earth and living slab, high level airtightness

Building materials: Rammed earth, Australian hardwood timber cladding stained, high levels of insulation to proposed and existing, steel framing minimised

Windows: Timber high performace double glazed windows

Active Heating & Cooling: MHRV (Mechanical Heat-Recovery Ventilation), Haiku Ceiling fans, Morso woodheater, hydronic towel rails

Lighting: Daylight maximised , LED fittings

Paints, finishes & floor coverings: Tectinic floor boards, low VOC paint throughout, external blinds shade doors & windows where necessary

Other ESD features: building footprint minimised to preserve garden for growing food

Photography by Amorfo

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