Balgowlah CLT Passivhaus 2020

House Notes – Balgowlah CLT Passivhaus

Purchase tickets for the event here.
This home is open for pre-booked tours only, the address will not be displayed.

This home is still under construction, please take care on site.

Balgowlah Woodland is a PassivHaus project 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 captures 55 T of CO2, avoids 20 T of CO2 annually which is the equivalent of removing 16 cars per year from Australian roads. The time taken to regrow the timber in German/Austrian forests – 15 seconds. The project has been designed and will be certified to the international stringent Passivhouse standard.

The triple glazed low-E argon filled timber windows ensure ample sunlight through the thick forest canopy above. The lot is home to two Cadaghi (Corymbia) trees, and neighbours a row of iron bark trees that all contribute to shading the site almost completely throughout the day. This was one reason why a PassivHaus was considered, as any other design was likely to result in the need for a large and constant mechanical heating and cooling demand. Automated external Roma venetian blinds block out summer heat and provide privacy to the occupants. The building is designed to maintain a constant 22 degree C temperature year round with no external heating or cooling load, and the heat recovery ventilation drawing nominal power (0.2 Wh/m3/h), are whisper quiet (20dB), keep internal air quality consistently high and have a 90% heat recovery rate to keep the temperature stable. The ventilation system is also de-centralised, meaning it avoids the need for any external ducting or internal cavity walls, and pushes the maximum floor space to the limits of the Complying Development standards allowed for the site. Due to the nature of the shade on the site, a traditional home built to Australian building code would require a large and constant heat load during winter and cooling during summer.

The building CLT panels were craned in using a 130T crane over 2 days, and made water tight in an additional 2 days with a ProClima vapour membrane. The triple glazed windows, weighing up to 200Kg each were hand installed and additional air-tightness tape sealed all the joints of the building to provide an initial blower door test value of 0.35 ACH, within the PassivHaus standard of 0.6 ACH. The building will be the first certified CLT PassivHaus in Sydney on completion. See further images here: Passive House Extension

The kitchen cabinetry uses locally sourced E0 emission rated , FSC certified materials. Energy demand of the occupants is predicted to be less than 1.8kW per day/person on project completion. The CLT building and front Bungalow will run exclusively on electricity with future PV panels planned to offset the entire energy needs of the house. LED lighting, a Sanden Eco Plus Heat Pump hot-water utilising a best-of-class 0.9kW to heat 300L water tank even during the middle of winter, and water efficient taps and shower heads and a toilet cistern connected to a 2000L rain-water tank complete the eco credentials of the building.

In addition to a certified PassivHaus, the brief to the building designer and architect was for a low-energy sustainable house at the same or lower cost of a knock-down rebuild project-home or similar size extension, health benefits of maximum indoor air quality with low-VOC materials, and a minimal construction time-frame with minimal onsite trades, all while being able to live in the existing front-building. This is a tall list of requirements to meet and we are pleased to say this has been met with exceptional success. The house is an extension to a ~100 sqm, 100 year old classic Californian Bungalow, that will be upgraded for higher energy-efficiency and improved indoor air-quality. We love the character of the bungalow and didn’t wish to destroy it’s history and street appeal by knocking it down which would likely have also forced us to remove the two beautiful Cadaghi trees that add much character, shade and benefits of native fauna to the garden. Cadaghi trees have a very unique characteristic that their trunks photosynthesise light, depicted by their exceptional bright green trunks when it rains.

The site is still a building site, we are taking registrations for a limited number of ticket holders, however the site is not suitable for children, strollers, prams, wheelchairs or anyone needing assistance at this stage. This is a chance to see what could become the future of construction that will produce massive environmental and health benefits to the whole of our country. The architect and interior designer will be onsite to give the guided tour. We are also fund-raising for our eldest son’s medical condition, as he was diagnosed with Langerhans Cell Histocytosis when he was 3 years old. All proceeds from the ticket sales will be donated to the Histocytosis Association for further medical research into the very rare condition. September is Histiocyte awareness month and the association gets funding for research only from public donors.

Tours available on the day with architect Knut Menden and designer Bettina Steffens. Please arrive on time for the scheduled tour.

Tour times:

• 10:00-10:45am
• 10:45-11:30am
• 11:30-12:15pm
• 12:15-1:00pm
• 1:00-1:45pm
• 1:45-2:30pm