Kirrawee Hempcrete Duplex 2024

House Notes – Kirrawee Hempcrete Duplex

The aim for building this single storey duplex was to incorporate social and environmental sustainability to provide affordable and accessible accommodation for us (a senior couple) as we age, as well as for our daughter (who has a disability).

The outcome is a highly liveable home, which won the 2023 Liveable Housing Design Award from the Building Designers Association of Australia (https://bdaa.com.au/national-design-award-winners-2023/). The design aimed to meet and exceed all Silver level criteria of the Liveable Housing Association (LHA). It also meets the 12 core design elements in the LHA Gold Level. In addition, we were also aiming for low maintenance, which affected the choice of external cladding and the use of native gardens to the street front.

Environmental sustainability aspects included passive heating design and attention to providing a highly effective insulation envelope for the building. This envelope uses hempcrete in external walls, structural insulated roof panels with no penetrations, and double-glazing on all external doors and windows. Rainwater tanks supply our veggie garden, and we are a host on the ShareWaste platform (https://sharewaste.com/), which allows us to collect and compost food scraps from various neighbours.

Social and environmental sustainability features have led to financial sustainability outcomes. Electricity usage is low, even now that we charge an EV at home. We can minimise our use of grid electricity by monitoring usage and solar production. Hence, most electricity bills since we moved in have been in credit. Using low-flow taps minimises our water usage and, therefore, our water bills. Our veggie garden provides us (and neighbours) with low-cost, delicious, fresh seasonal veggies all year. In 2022, we saved over 2 tonnes of food scraps from landfill.

Sustainability Features

Years Open
2024
ENERGY AND WATER EFFICIENT FEATURES
    • Energy efficiency:
    • Draught proofing
      Efficient lighting
      Efficient appliances
      Energy monitoring

    • Energy efficiency:
    • Smart energy management by owners/occupiers
    • Passive heating cooling:
    • Cross ventilation
      Deciduous planting around house
      Passive solar designed home
      Shading
      Thermal mass
    • Active heating cooling:
    • Ceiling fans
      Split system airconditioner
    • Water heating:
    • Hot water heat pump
    • Water harvesting and saving features:
    • Rainwater storage - Above ground
      Rainwater storage - Underground
      Stormwater management
      Low flow shower heads
      Low flow taps
    • Average water consumption per day:
    • 74.9 L (not inc. rainwater collected)
    • Underground rainwater storage type:
    • Underground tank
    • Underground rainwater storage Size:
    • 2 x 5,000 L
    • Above ground rainwater storage Type:
    • Above ground tank
    • Above ground rainwater storage Size
    • 9,000 L
    • Energy Efficient Lighting
    • LED lights throughout
      Natural daylight
    • Electric Vehicle Type
    • BYD Atto 3 and BYD Dolphin
    • Window Protection:
    • Adjustable Shading
      Drapes/curtains
      Eaves
      Honeycomb blinds
SUSTAINABLE & RECYCLED MATERIALS
    • Sustainable materials:
    • Long life Colorbond cladding Permeable pavers Low and Zero VOC paints Demolition: Recycling of demolished tiles, bricks, gyprock
    • Recycled and reused materials:
    • Appliances
      Basins/sinks
      Bathroom cabinets
      Benchtops
      Bricks
      Concrete
      Tapware
INSULATION SPECIFICATIONS
    • Insulation Type:
    • Under-roof
      Ceiling
      Internal walls
      External walls
      Floor
    • Ceiling Type:
    • Bulk – glass wool
    • Ceiling Rating:
    • 2.0 (to dropped ceilings)
    • Floor Type:
    • Wafflepod
    • Under Roof Insulation Type:
    • Insulated panels
    • Under Roof Insulation Rating:
    • 5.2
    • Internal Walls Insulation Type:
    • Bulk – glass wool
    • Internal Walls Insulation Rating:
    • 2.0
    • External Walls Rating:
    • 2.85
    • External Walls Type:
    • Hempcrete
RENEWABLE ENERGY SPECIFICATIONS
    • All-Electric Home?
    • Yes
    • Energy star rating:
    • 7.2 (average)
    • Renewable energy used:
    • Solar PV grid connect
    • Size of PV system:
    • 2 x 7.26 kW
    • Average Daily Energy Consumption:
    • 3.6 kWh (total self-consumed solar both sides), 5.0 kWh (total grid both sides inc. EV charging)
HOUSE DESIGN SPECIFICATIONS
    • House Size
    • 330m2 (total both units)
    • BAL Rating
    • No BAL rating requirements at time of construction
    • Roof
    • Insulated panel (sandwich panels)
    • Wall Materials
    • Hempcrete
      Metal (Colorbond)
    • Window and Door Types
    • Awning
      Double glazing
      Louvre windows
      Low-e, films
      Sliding windows/doors
    • Universal design accessability
    • Multi-generational
      Universal access
      Wheelchair accessible
    • Universal Design Features
    • 80cm minimum door opening width
      Contrasting colours and material for vision impaired
      Flush thresholds (no lip) to all external doors
      Hobless showers
      Kitchen bench/table for wheelchairs to access (75-85cm high)
      Lever handles for doors (no knobs)
      Minimum 110cm wide hallways
      No stairs/steps
      Power points at 60cm above floor level and 50cm from internal corners
      Pull out shelving easily accessible in wheelchairs
      Ramps and path gradients must be less than 20:1
      Shower head on rail for various heights
      Slip resistant flooring
      Space around toilets for ease of access in wheelchairs
      Various heights for benches in kitchens
    • Number of bedrooms
    • 6
    • Number of bathrooms
    • 4
GARDEN AND WASTE REDUCTION
    • Garden / Outdoors
    • Permeable paving diverts stormwater run-off to garden and generally slows stormwater run-off. Bird bath for local birds.
    • Garden / Outdoors
    • Composting
      Edible garden
      Local indigenous plants
      Organic
      Native plants
      Water wise plants

    • Waste Reduction Practices:
    • Book exchange/library
      Compost all food scraps
      Make jams/conserves
      Pickle and preserve food
      Recycle
      Repair
      Recycle coffee grounds from nearby cafe's
      Swap with friends and neighbours
      Waste free/reduced construction site

    • Other Waste Reduction Practices:
    • Host for ShareWaste (accept food waste from neighbours for composting - 2000kg in 2022)
HEALTHY HOME FEATURES
    • Healthy home features
    • Cabinet design to minimise dust collection
      Carpet free - tiles/concrete/timber flooring throughout
      Chemical free cleaning products used
      Cross flow ventilation
      Indoor plants for air filtration
      Lime render/wash
      Low VOC paints/sealer/varnish
      Natural fibre furnishings
      Natural light and ventilation
      Natural oil sealer/finishes
      VOC free paints/sealer/varnish
      Wax based sealer/finish
Location
Kirrawee NSW 2232
    • Housing Type:
    • Duplex
    • Project Type:
    • Knock-down rebuild
    • Builder
    • Sowden Building Solutions (Nick Sowden)
    • Designer
    • Connected Design (Tracy Graham)

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