CLT Passivehouse Balgowlah 2020

House Notes – CLT Passivehouse Balgowlah

This 2-storey extension to an existing house from the late 1920s was erected in a tight backyard in the northern suburbs of Sydney. The budget for the house was modest, but still required a high quality finish to achieve the client’s request for creating a sustainable, healthy living environment for a young family.

Retaining the large established gum trees on site while maintaining privacy as well as the connection to nature, shaped the building form . The house allows its occupants to feel as though they are living amongst the trees.

The cross-laminated timber (CLT) structure was prefabricated offsite, including the stair and cut-outs for lighting, power and equipment, and installed highly efficient and precisely (2mm tolerance) in just 15 hours.

Designed to the Passivhaus standard the thermal efficiency of the building is maximised and by using mass timber a significantly reduced carbon footprint was achieved.

This is now the first certified residential Passivehouse built in cross-laminated timber and one of less than 25 Passivehouses in Australia.

The interior of the building features fully exposed timber walls, floors and ceilings that, in combination with the heat recovery ventilation system, will ensure a healthy natural indoor environment. The building is designed to work year round without the need for artificial heating and minimal cooling, which is made possible by the airtightness of the envelope, high level of insulation, triple glazed timber windows and external shading.

The external facade is clad in local untreated Blackbutt timber battens left to naturally grey over time.

Sustainability Features

Years Open
2020
ENERGY AND WATER EFFICIENT FEATURES
    • Energy efficiency:
    • Draught proofing
      Efficient lighting
      Efficient appliances
      Energy monitoring
    • Passive heating cooling:
    • Cross ventilation
      Deciduous planting around house
      Heat recovery ventilation system
      Shading
    • Active heating cooling:
    • Ceiling fans
      Heat exchange ventilation system
      Split system airconditioner
    • Water heating:
    • Hot water heat pump
    • Water harvesting and saving features:
    • Rainwater storage - Above ground
      Low flow shower heads
      Low flow taps
    • Average water consumption per day:
    • 80L
    • Above ground rainwater storage Type:
    • PVC tank, Eaves water system for improved water quality (surface tension guttering, with in-built leaf guard in one-piece colourbond)
    • Above ground rainwater storage Size
    • 2,000L
    • Energy Efficient Lighting
    • LED lights throughout
      Natural daylight
    • Window Protection:
    • Adjustable Shading
      Automation/controls
      Deciduous tree/vegetation
      External window hoods/surrounds
SUSTAINABLE & RECYCLED MATERIALS
    • Sustainable materials:
    • This PassivHaus project has been designed to provide a multitude of benefits to the environment and occupants. Through the use of sustainable materials such as FSC/PEFC certified Cross Laminated Timber (CLT) for all internal and external walls, floors, ceilings and roof, wood-fibre insulation, and sustainable blackbutt timber cladding – the house stores 55 T of CO2, and avoids 20 T of CO2 (compared to traditional construction) which is the equivalent of removing 16 cars for a year from Australian roads. The time taken to regrow the timber in German/Austrian forests for the entire project is 15 seconds. The project has been designed and has been certified to the international stringent Passivhouse standard.
    • Recycled and reused materials:
    • Bricks
      Railway sleepers
INSULATION SPECIFICATIONS
    • Insulation Type:
    • Under-roof
      External walls
      Floor

    • Floor Type:
    • XPS
    • Floor Rating:
    • R2.5
    • Under Roof Insulation Type:
    • Wood fibre insulation external
    • Under Roof Insulation Rating:
    • R6.0
    • External Walls Rating:
    • R4.0
    • External Walls Type:
    • Wood fibre insulation
RENEWABLE ENERGY SPECIFICATIONS
    • All-Electric Home?
    • Yes
    • Average Daily Energy Consumption:
    • 1.8kWh
COSTS AND COST SAVINGS
    • Total cost of home when constructed:
    • $630,000
    • Cost estimate of sustainable home/features:
    • $25,000
    • Estimate of annual savings:
    • $2,000
HOUSE DESIGN SPECIFICATIONS
    • House Size
    • 110m2
    • BAL Rating
    • No BAL rating requirements at time of construction
    • Roof
    • Metal (Colorbond)
    • Wall Materials
    • Timber

    • Wall Materials
    • Cross-laminated timber solid walls
    • Window and Door Types
    • Low-e, films
      Tilt and turn
      Triple glazing
      180 degree opening doors
    • Universal Design Features
    • 80cm minimum door opening width
      Flush thresholds (no lip) to all external doors
      Hobless showers
      Lever handles for doors (no knobs)
      Minimum 110cm wide hallways
      Shower head on rail for various heights
      Window openings easily accessible
    • Number of bedrooms
    • 2
    • Number of bathrooms
    • 1
GARDEN AND WASTE REDUCTION
    • Garden / Outdoors
    • Chickens
      Composting
      Natural swimming pool
    • Waste Reduction Practices:
    • Compost all food scraps
      Recycle
      Waste free/reduced construction site
HEALTHY HOME FEATURES
    • Healthy home features
    • Airtight house design
      Automated ventilation system
      Carpet free - tiles/concrete/timber flooring throughout
      Chemical free cleaning products used
      Cross flow ventilation
      Formaldehyde free cabinets
      Heat recovery ventilation (HRV)
      Low VOC paints/sealer/varnish
      Natural light and ventilation
      Natural oil sealer/finishes
Location
Balgowlah NSW 2093
    • Housing Type:
    • Standalone House
    • Project Type:
    • Retrofit/addition
    • Builder
    • Conor Murphy
    • Designer
    • betti&knut architecture

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