Drumkerin – It’s Not Just About the House

There was a time when solar hot water and PVs on the roof deemed a home innovative and very green. Passive solar design and double glazing were considered leading edge and good examples were hard to find. We’ve now moved far beyond that in our knowledge and capacity for designing passive solar, energy-efficient and environmentally friendly houses. As architects, we have the ability (and responsibility) to design better. With rising emissions and a changing climate, it is essential that proactive sustainable architecture becomes the norm as a contribution to reducing our carbon footprint. But it’s not just about the house. Examples of the responsible building need to be much more than that to have a significant impact on our collective carbon footprint. It’s not just about good design or the right materials and systems. It’s also about living, behaviour, locality, community inclusiveness. I recently designed and completed Drumkerin, my home office in Armidale with many of the above elements. Yes, it faces true north and has good zoning, lots of insulation, thermal mass and double glazing. But it also has a large component of recycled and upcycled content. It incorporates innovative materials such as PCM (phase change materials) and low tech solutions such as nil-energy evaporative cooling. But again, it’s not just about the house. It aimed to be an example of low carbon, minimal footprint, community embracing living in a regional city. During the design process, a holistic approach to all decision-making influenced the choices throughout the project (as architect and client), balancing each eco-initiative against a set of criteria:

1. practical – would it be possible, would it work, would it last? 

2. sensible – was it worth the effort, does it balance with other ideas or negate other benefits?

3. aesthetic – does it look good, does it complement the rest of the house? 

4. financial – is it affordable, is it cost-effective, what’s its payback and would its benefits last?

The answers to these questions have proved true in the completed project with a significant reduction in our carbon footprint while being an exemplar for others. The house sits on a subdivided block near the centre of the city, retaining the 1920s house at the front, with sympathetic and appropriate development behind – and maximising already existing urban infrastructure. As part of infill development, a precedent was fought for – and agreed to with the local council – to retain all stormwater and roof water on site. To have connected to the council’s drainage system 100 metres away would have been cost-prohibitive and halted the project. Instead, we created a total storage capacity of 50 kl, enabling us to still water the extensive permaculture based garden despite level 4 water restrictions (ironically not even on the agenda at the time). But the tank design was, like most decisions in this project, multifaceted. We wanted to keep as much water as possible for the garden. The house straddles an old tennis court, so is partly at ground level, then continues over the tennis court with 38 kl water tank storage beneath. On hot days, with only a high clerestory window
open, cool air is pulled across the tank from screened openings on the southeast corner through a vent in the tank/ hallway junction – evaporative cooling by default. So as well as achieving this for this specific project, future infill development might also be able to proceed on a similar basis. This project has added to the overall development opportunities of the city in a practical way. The house itself, while only rated as 6.2 by NatHERS, is performing well beyond the predictions, despite increasingly hot summers. The challenge is to design for future weather changes, even if it means a less efficient house in the short term. Monitoring of energy and temperature shows that for up to nine months of the year, the house is in fact 10-star performance – with no energy required to heat or cool, even with constant low-to-mid 30s in summer. For the shorter winter, months (with sub-zero temperatures) figures indicate up to 9.5-star performance. Through the use of CatchPower software, we know exactly how much energy is being used to heat the home. Designed to divert excess PV power to hot water systems rather than the grid, this was the first time used to divert the energy to a heat bank instead – effectively storing excess energy as heat. But even adding this energy into the calculations, the house is still well below predicted energy usage. Part of the reason may be the software’s inability to recognise innovative materials such as the PCM, which provides a diurnal cycle of heat gain and release much faster than the lag times of conventional thermal mass. Or the inclusion of an attached glasshouse that directs warmed air into the house on sunny winter days. And, of course, behaviour (airlocks and double glazing are only effective if closed in cold weather or opened for warm weather). During construction, there was a conscious choice to prioritise local trades and materials to support the local community. Although it doesn’t always reduce the mileage on transport – as many materials and items still need to come from elsewhere – the support then spreads to regional, state and national, ahead of global. It’s all part of the bigger picture. A high component of sustainable, recycled and upcycled material was essential to improve the embodied energy of the building. While there are now many off-the-shelf products available, they won’t necessarily be used unless architects specify the right product to ensure the right content. Knauf plasterboard and insulation, Urbanline decking (wheelie-bin offcuts and sawdust), recycled fly-ash, Weathertex cladding, secondhand bricks – these are the easy ones. Furthermore, we incorporated reconfigured bookcases and extensive use of timber offcuts; hardwood parquetry seconds for benchtops; a hoop pine ceiling removed from the demolished garage reinvented in the bedroom; old gas brackets rewired for wall lighting; and even the toilet door from a demolished garage was made larger as a new front door. We’ve used secondhand cupboard handles, doors, a basin, glazing and other items that look good as new. Non-standard processes used included Arcpanel self-supporting roofing and installing thermal breaks between slabs and supporting walls, and to external slabs.
More inventive materials also included the use of four 1860s ironbark columns found in a secondhand store; metal screens (leftover after machinery is punched out) to create the glasshouse wall and a front screen door; secondhand balustrade glazing for the glasshouse roof and the kitchen splashback; used pallet racking as the bones of the walk-in robe, with Ikea seconds for doors and drawers; and a sulky wheel converted into a light fitting. This all adds to reducing the embodied energy and depletion of resources required for the build. But again, is that enough for a well-designed, energy-efficient, low demand, sustainable house? Even the most efficient machine can still be operated badly – and the most sustainable building can still be occupied ‘badly’. Appropriate behaviour is essential to the success in reducing the building’s impact during occupation post-construction. By providing well-designed comfort, ample natural light and fresh air, energy demand is reduced, but it still relies on good behaviour to maximise the benefits. Many aspects of how the house was built and its location and use take its sustainability a step further. Staying close to the city, we can still walk to most places rather than use a car. Instead of including a third (and hardly-used) bedroom, there is a gate in the fence to the nearby motel. The vegetable garden and food forest feed us; reduce our food miles; provide excess for the farmers’ market or to swap; and bring over 40 different birds to the garden. Despite generating excess power with the PVs, the decision to stay connected to the grid is in anticipation of future peer-to-peer trading and a possible community grid. Involvement in house and garden tours also enables us to share ideas with the broader community. It’s not hard to design, build and live in responsible housing, and at no more cost than much of what’s being built. But it’s the bigger picture that’s making this project more than just a good house. As a winner of the 2018 Architecture & Design Sustainability Awards (for a new single dwelling), the judges commented:

‘Ticking all the boxes in a sustainable building is – thankfully – increasingly common. Buildings that are restorative, contributing to restoring a functioning environment, are rarer. Really uncommon are restorative buildings that are both funky, biophilic and very human. Drumkerin is all those things.’

As an eco architect, I aspire to set a good example. As well as being a pleasure to live and work in, Drumkerin has also achieved this for myself and my practice. The intent was to downsize, but in so doing we have provided Armidale with an example of a better solution to current building trends. While there’s no silver bullet – every client, site, the house is different – it provides an array of ideas and options for creating a successful eco-home. 

Mahalath Halperin is an environmental architect who provides a sustainable and holistic approach to her services in Armidale. In the past, she has been the chair of the Australian Solar Energy Society, vice president of the International Solar Energy Society and chair of NSW Chapter’s Country Division.