This stunning hempcrete house in central Victoria was designed by Altereco Design, with a brief to create a functional and beautiful space that would be thermally comfortable and simple for the owners to build themselves. The owners vision emphasised solar passive design principles and the exploration of Hempcrete as a building material, to create a haven that showcased elegant simplicity and was both considerate of the environment and mindful of the climate.
Altereco’s design response embraced the concept of “just enough”, with their goal of a small footprint achieved at just 75 square metres (comparing extremely favourably to the average Austalian house which is a whopping 242sqm!)
The design needed to deliver outstanding thermal performance in harsh, sub zero conditions, being 740m above sea level. The result is a home that can maintain comfortable indoor temperatures of 20°C without the need for additional heating.
Sustainable Features
Construction
- Small footprint (77sqm)
- Passive solar design: Northern orientation with wide eaves for shading in summer.
- Thermal mass: Polished concrete floors and internal hempcrete walls for passive heating in Winter.
- Highly insulated.
- Airtight construction made with 300 mm HempCrete walls with lime render for external weatherproofing and clay.
- Aliclad high performance double-glazed windows with low e glass.
- House is carbon negative and will sequester carbon for the life of the building.
- Hemp is compostable at end of life (at least 100 years away).
- Renopass lime render to exterior of hempcrete. Lime plaster to interiors.
Energy + Water
- All electric home.
- Renewable energy: 5.2kW solar PV system on shed.
- Rainwater harvesting: 50,000L and 60,000L stainless steel water tanks (repurposed wine vats).
- Wormworx 3000L worm farm biological wastewater treatment system installed by Zenplumb.
- Reclaim Energy heat pump with 315L glass enamelled steel tank from t2zero.
Sustainable materials
- Reclaimed messmate timber floorboards used for upstairs flooring, architraves, skirting boards, shelving, doors and kitchen cupboards.
- Livos oil finish to joinery and burnished concrete floors.
- Bushfire protection: fire-resistant Australian hardwood posts, cladding and eave linings; external timber painted with intumescent paint developed by the CSIRO to reduce fire risk due to embers.
- Haiku fan by Big Ass fans 152cm upstairs and downstairs set to automatically come on at a certain temperature.
- Decidious trees planted to east and west of house providing shade in Summer and letting sun into the house in Winter.
- Careful management of building waste – most able to be reused or repurposed. No skip bin required and only 2 small trailer loads of waste went to landfill.
“We feel really proud of this house. It feels cosy and peaceful, with pared back finishes in burnished concrete, warm timbers and natural clay walls. It maximises views of our garden, the dam and the wombat forest and feels so comfortable, year round. We were closely involved in the design, research and sourcing materials and finishes. We did all the work ourselves that didn’t require registered trades. Now we enjoy stable comfortable temperatures inside no matter what the weather is doing outside.”
Using Hempcrete to construct the home brought many benefits. Not only does it exhibit exceptional resistance to fire, pests, and mould, ensuring a secure and long-lasting structure, but the breathability of the lime and clay plastered walls also guarantees a constant supply of fresh air while effectively regulating humidity levels.
Building a hempcrete house also comes with a range of environmental benefits, including the unique ability to sequester carbon from the atmosphere. Hemp is a natural, fast growing and renewable material, qualities that contribute to the reduction of carbon emissions and foster a more sustainable future.
The site was oriented to the North (ideal in the southern hemisphere) and uses an internal hempcrete wall and burnished concrete flooring for thermal mass, the combination allowing the natural heating from the sun to be absorbed by the thermal mass and released well into the evening.
“The performance of our house has exceeded our wildest expectations. We do not use any air-conditioning and rarely need to use any heating. The house stays in a comfortable temperature range between 18 and 21° most days, even on frosty nights. The Hempcrete walls passively regulate the relative humidity inside the house to 40 – 50% when it’s 99% outside.” – Owner
This home is not only delightfully warm and tactile, delivering the home the owners dreamed of, but also an inspirational case study for others to emulate.
