Renew Magazine

When: February 17th, 18th, 19th

Where: Village Roadshow Theatrette 
at the State Library of Victoria

Tickets: Cost $500 per person, with 15 Student discount tickets available at $300 each. Visit www.earthship.com/australia

Limited seating is available so advance purchase is recommended.

Attendees achieve credit toward the Australian Earthship Biotecture Academy.

Program

Friday February 17th
 from 10am – 12pm History of Earthships discussion/presentation on how and why they evolved.

2pm – 5pm Solar/Thermal dynamics: discussion/presentation on how the Earthships heat and cool themselves and how this is integrated with the structure and climate.

Saturday February 18th 
from 10am – 12pm Custom Earthships: discussion/presentation on custom Earthships and how to design them.

2pm – 5pm Earthship Systems: discussion/presentation on specific details of the Earthship Systems independent power, water, sewage and food production.

Sunday February 19th 
10am – 12:30pm Earthship Disaster Relief projects around the world discussion/presentation on how Earthships have evolved with these projects.

1pm – 3pm Types of Earthships – discussion/presentation on the various types of Earthships and how to get started on your own

Led by Michael Reynolds with guest appearance and presentation by Martin Freney, PhD Candidate School of Architecture, Landscape Architecture and Urban Design University of Adelaide. Martin Freney will present scientific data to substantiate Earthship performance.

East Coast tour

Shorter presentations will be held along the east coast including Northern Rivers February 23, Gold Coast February 24 and Sunshine Coast February 25.

For further details, go to the Earthship website.

ReNew is a proud media partner of the Melbourne Earthship Biotecture Seminar

On the topic of windows and glazed doors, the workshop covered design considerations that can have a big impact on the passive thermal performance and energy efficiency of the house, including size, orientation, frame and glazing type and shading. It also addressed the extra issues that need to be considered when building in a bushfire prone area and looked at some windows, frames and shutters rated for use in the higher Bushfire Attack Level (BAL) zones.

Here’s an overview of the workshop’s main points on glazing in high BAL zones below. Listen to the full, highly informative presentations on the ATA website at www.ata.org.au/bushfire.

BAL zones
A home site’s Bushfire Attack Level (BAL) is determined by a number of factors including the area’s Fire Danger Index (a measure of the probability of a fire starting), the type of vegetation and its distance from the house, and the slope of the land. The recently introduced new building regulations impose more stringent requirements on design and materials as the site’s BAL increases; for the top two levels, BAL-40 and BAL-FZ (Flame Zone), these are aimed at protecting the house from ember attack, a fairly to very high likelihood of direct flame contact and radiant heat up to 40 kilowatts per square metre (for BAL-40) or even hotter.

Requirements for windows in high BAL zones
The requirements for lower BAL zones specify various combinations of frame material, toughened glass or double glazing, and steel or bronze mesh screens to openable windows to prevent ember attack. In BAL-40 and BAL-FZ zones, however, the requirements are stricter.

The grid-interactive system was installed with future fires in mind, with a battery backup to ensure electricity supply during a blackout. The system now fulfils most of their energy needs in the new house, although the true status of their bill, and usage, remains a mystery due to Tru Energy’s long billing delays.

The improvements don’t stop there, with the entire rebuild showing a greater resilience to future bushfires with the bonus of improved energy efficiency.

Learning from the past

The old home was a single-storey brick veneer with a W-roof profile that Janet describes as a perfect ember trap, single-glazing to the west and was like an oven inside in summer. “We had a big wooden deck which probably went up in flames quite nicely. We knew it was a risk but we were a bit naïve perhaps and didn’t think a fire would come through, or that it would be that severe.”

After losing everything it was difficult to know where to start with rebuilding. Two things helped shape their rebuild though: a meeting with architect Ian Weir and visiting open days at other sustainable homes.

They’d first seen Ian on television and discovered that he offered free consultations to people affected by the Black Saturday bushfires. His advice was to keep the building shape as simple as possible with few nooks and crannies to limit the places for embers to gather.

Visiting a house in Healesville, Janet grew to love a unique construction duo of rammed earth and scyon, a thick but lightweight cement composite cladding which looks just like weatherboard. “The house felt solid and inside it felt grounded and safe.” The couple engaged the designer of that house for their rebuild, heeding Ian Weir’s advice to simplify the shape and opting for a flat, slightly angled roof profile that the embers would slide off. After all, the roof had been a weakness in the old house.

This second consideration loomed even larger as it became clear that politicians would be treating the problem as a political rather than an environmental one.

The basics of thermally efficient building design are well known; they have been listed and discussed in books for years. It seems that for some strange reason they are just not generally implemented all together or in full. Perhaps this is due to a tendency to build down to a price rather than up to a standard?
The three principles of thermally efficient building design are GMI.

G: Glazing

Windows are ‘holes in the wall’; glass in the window will generally keep the rain out but heat can pass readily through. We want to keep summer heat out and winter heat in so at Galaxy Hill we have used double glazing. In addition, the windows have internal screens ‘velcro-ed’ across the top to seal against convection and external shutters to add to thermal insulation. We have made sure that the window and door frames actually fit tightly into the wall structure, so there are no ‘leaks’ through mini cracks in the wall.

M: Mass

In particular, thermal mass, where the solid material is there to lock in heat, whether it is also structural or not. Note that the external brick wall on a conventional brick veneer house is non structural. It is essentially just for show. It also allows moisture to seep into the cavity which may be undesirable.
At Galaxy Hill we have built a reverse masonry veneer house. The external wall cladding is in the form of timber laminate with very little mass. Thus it doesn’t retain heat overnight in a hot summer and it keeps moisture out completely!

The internal thermal mass wall stores thermal energy and in the process keeps the temperature stabilised to a narrow, comfortable range.

Find the full article in ReNew 114

The farm came with a large home—16 rooms over five levels with two open-plan living and entertaining areas—the main selling point being we liked this style years ago.

The three concrete slabs stepping down the rolling red soil hills already had hydronic in-slab tubing, heated from a diesel furnace along with the tap water. Cooking was done by bottled gas, and there were three slow-combustion wood heaters in the two living areas.

Philosophy and design

We are very keen on sustainability and want to minimise our carbon footprint, both in the home and our farm’s beef production. We were prepared to spend some money converting the heating system for a large reduction in running costs and emissions. The farm has many large trees and limbs are always falling, so using solar-powered heating and hot water, boosted by a wood-fired heater, seemed like a sensible idea.

We found the solar collectors we wanted and set system parameters. Our plumber designed and built the conversion, changed the skylights, re-flashed the house and updated much of the water collection. We added ideas as it was built over several months.

The home

The climate is cool temperate with few frosts and the house is sited on a southern slope in foothills.

We are at latitude 38.005°. There is some unavoidable morning shading in winter from a roadside glider possum habitat of magnificent eucalypt trees over 40 meters high, 30 meters away and uphill on the northern road boundary. The outside temperature ranges between 2°C and 42°C but the house has such a large thermal time constant that living areas stay between 17°C and 22°C in winter, and no more than 25°C after a run of hot days.

The house design is classic 1970s double brick with rough-sawn, exposed beams in eight meter cathedral ceilings.It had hardwood french and other windows with single-glazing throughout, and sad plastic-vented skylights. Everything was coloured mission brown.

The designer ignored the 16 kilometre view to the Strzelecki Ranges and the valley below, and modern principles of house alignment for passive heating and cooling. However, at least the sun does not load up the interior. There are a few, small windows to the east, with excellent shading from canvas blinds, and large french windows to the west. These are shaded by a pergola and close battens. The home’s north face is stepped into the hill and the windows are totally shaded by a brick cloister with archways: a very sensible design providing a great spring breakfast area.

The kitchen, living and lounge rooms, study and billiards rooms are open plan and interconnected on three levels, which does create air currents, especially with such high ceilings. We have been slowly renovating, as one does with a retirement income.

The aim is to convert major glass in living areas to high-efficiency glass and to install as much double glazing as we can afford. So far our plumber has retrofitted seven double-glazed, openable skylights. The local glazier replaced 11 clearstory windows and made three panels openable to draw up cooling air from the lower levels when a summer cool change arrives.

We use pressurised tank water for most of the home, buildings and farm animals. There are 245,000 litres available in concrete tanks, linked by a 50mm buried ring main. Our local irrigation contractor built a fire sprinkler system for all buildings on the farm, which was essential when the wind changed during the Black Saturday bushfires in 2009. Our 100-year average rainfall is 1100mm; we received 1178mm in 2010 so we always have an excess of stored water.

There is a 1.5kW solar power system on the roof, bringing an income and well offsetting the minor energy drain from the small pumps moving water into the hydronic heating and up to the solar collectors.

Hydronic system components

Our heating system has three sources of heat:

• 36 solar-collecting vacuum tubes (rated at 5.8kW)
• wood-fired, slow combustion fire, with flue water jacket
• two gas-fired instantaneous hot water boilers.

The service courtyard where most of this hybrid heating and hot water system is hidden looks Heath Robinson, but it is a credit to our local green-accredited plumber at Baw Baw Plumbing and his team. He always knows about the latest efficiency innovations and was a terrific speaker at our Landcare group’s Green Energy field day.

Heat storage

A custom made 1000 litre stainless steel tank with 75mm of insulation and a small header tank is the heat storage. It’s similar to those made for the local dairy industry. Hot water is not drawn from this water but via three heat exchanger coils in the tank, with the solar one at the base, the hydronics one at the centre and the hot water service at the top. Each is 11 metres long.

Solar collectors

I contacted eight retailers advertising evacuated tubes. Disappointingly, not many responded.

From sellers’ claims, the most efficient collectors I could find were Ritter (labelled APR), a Chinese-made German design imported by Sunplus CPC. We bought 1.6m long evacuated tubes in banks of six, with parabolic mirrors to direct extra sunlight under the tubes. Our budget limited us to triple the normal number of tubes recommended for hot tap water and a 1000 litre hot water storage tank.

The collector bank of 36 tubes is fixed to a 1.6m by 4.4m aluminium frame facing 15° west of north. I asked for it to be tilted steeper than the roof’s 17° at a calculated winter solstice angle of 60° to collect maximum energy for winter. This reduces excess summer yield and steam problems.

Importantly, the plumbing route for the tubes allows us to add more down the track.

The north roof with evacuated tube collectors for the heating system and a 1.5kW solar power system.

Inside the solar control and storage area

Solar-heated water pumping

This is a rainwater-filled closed loop heat-exchanger. Water from the storage tank coil is lifted about five metres up to the solar array by a 3-speed 30 watt 240v hot water pump with throttling valve, giving infinitely variable flow. It usually runs at 0.2 bar boost. A Zilmet model 20013 50 litre cylinder stores system over-pressure up to four bar from summer days, backed up by a blow-off valve to save water loss on hot days.

Relief valves

Four high spots in the solar array and wood heater circuits have auto air-bleed valves, allowing only air and steam to escape.

Wood-fired slow combustion heater

We changed the third wood heater to a gas unit for quick response to a cold home.

After the first winter with the new system, an existing free-standing Saxon unit in the living room was retrofitted with a 550mm tall stainless steel heat exchanger in the first part of the flue. It burns quietly from late autumn to early spring on wind-fallen mountain ash and blackwood harvested around the farm. Water to the flue exchanger is drawn from the base of the storage tank and delivered back to the top. Piping is about 25 metres long and rises about 3 metres. It is insulated with 25mm thick foam tubing and cased in colorbond. A 240v thermostat in the output pipe in a wall behind the heater senses output temperature and controls another small circulating pump at the storage tank, moving two litre slugs of hot water at 50 °C into the storage tank every few minutes. This heater provides around half our total hydronic heating in winter.

Gas boilers

Tap water is delivered via an instantaneous Rinnai V1500 gas boiler which adds heat if stored water is not 50°C. There are no adjustments for the home owner. Electronics in this unit can be damaged by our emergency home generator, so we cannot run the hot water when mains power fails, which it does for several hours at least four times per year.

Hydronic water supply is delivered to the mixing valve via a Sime Format 34e instantaneous gas boiler, rated at 11.2kW to 34kW, large enough to heat the whole home on its own. It adds heat if needed and has user-adjustments for output temp (set to 35°C). Its instruments display output temperature and pressure. The pump within this unit is also triggered by the thermostat in the master bathroom, sending heated water to a Hydrotherm P-600 Platinum tower rail, 2.2m by 600mm wide, helping provide some extra hydronic heating to the bathroom.

Both boilers stay on in summer as they do not use any gas unless heating water.

Heat users

The house is heated by hydronic coils in five zones in three concrete slabs at descending levels in the house, plus a fan-assisted radiator in the living room. Two manifolds are fed from a mixing valve, and water circulated by five, 240v Grunfos thermostatically-controlled 3-speed pumps.

We have only activated the outer coil on the lower slab coils. We are very fortunate that it flows via the master toilet and bathroom, laundry, kitchen, two guest bedrooms and to the living room on the lowest slab.
Hot tap water runs throughout the house with all piping insulated with 25mm thick foam tubing. External piping is further encased in 90mm stormwater piping.

Water delivery controls

Hydronic water is blended by the original tempering valve supplying two hydronic manifolds. Tap water is held to 50°C by a Reliance Heatguard Ultra tempering valve. This setting can be altered.

The three room thermostats in the home are very clever Honeywell model CM 907. They can be programmed in time blocks for every day of the week, can be over-ridden for one time block, set to a fixed temperature and adjusted for daylight savings. The lower slab thermostat in the living area also masters the upper slab in the entertainment area. The second thermostat in the upper level study controls the mid slab. The third thermostat in the master bathroom controls water to the towel rail.

Operation
Solar control

The electronic differential controller, made by Whitnic Services of NSW, gets its data from 10volt thermistors, one at the array output and one at the storage tank top. It has three modes and a red light indicates the pump is on, which I positioned to see from the back door.

Gas supply

Gas was originally supplied by a bank of 40kg cylinders. These were replaced by a 190kg truck-filled tank, with pressure reducers at two boilers, and a circuit supplying the guest kitchen and fast-response gas heater in the living room.

Owner adjustments and monitoring

I wanted to monitor input and tank temperatures, so I bought three $10 electronic indoor/outdoor thermometers with remote sensors and mounted them next to the differential controller. I can feel the input arriving from the solar array, with one attached to the lowest hot connection on the storage tank, indicating roughly how much hot water is in the tank, and the other reads water delivery to the taps. These have max/min displays as well, useful for checking array performance or pump adjustments. An old clock-type dial indicator measures the temperature of water returning from the hydronic system, a rough indication of how much heat is in the slabs.
The electronic gauges are particularly useful to know how much heated water is available for a big load such as a spa fill or running the lounge room radiator. Monitoring incoming temperatures from the array allows me to tune up the flow rate for best performance just below steam occurring, and tells me if we have any problems when it’s pumping. An improvement would be digital readings from the differential controller’s thermistors.
We can adjust slab heating times in two zones and towel rail temperature, and boost heat in the lounge room by activating the fan-assisted radiator. We can control the temperature of the water leaving the fire water jacket. We cannot alter the temperature trigger points for the solar array. It might be useful to keep it pumping above 80°C to stop a steam blockage occurring.

Current settings

Thermostats have six available time block settings, with the initial settings for the slab thermostats listed below:
TIME      TARGET TEMP
6am          20°C
8                18°C
Midday   18°C
5.30pm   18°C
8.40pm   13°C
10.30pm 8°C

When there’s a run of low solar-energy days we run the wood fire hotter. When there’s sunny days predicted, we can use less wood, or not light it.

As autumn starts, we open the hydronic valves and drive the wood heater hard to put as much heat as possible into selected slabs prior to cold snaps and overcast winter days. On a run of overcast days we open the damper on the wood heater.

Fine tuning and problems

We run the collector pump at the lowest of three speeds and fine-tuned the flow to 1.5l/min on the advice of the plumber. We’ve learnt that in summer we need to double the flow rate to avoid excessive pressure build-up.
The original thermistor on the solar array burnt out after one year and the surrounding insulation was charred! The new importer tells me the replacement thermistor is a tougher type.

Anything that stops the circulating pump while there’s sun on the vacuum tubes can create a blockage in the circuit that the circulating pump cannot overcome. When the thermistor on the roof fried, and when we lose power when the sun’s on the tubes, pressure builds up and the closed loop finally drops below it’s 0.2 bar pre-set pressure. This stops circulation for that day and we lose a little water as steam. When the pump is alive again it fails to get water circulating if the array is in sun. So if the system pressure gauge is zero, I know circulation has stopped and must be topped up. To fix it we fit the garden hose onto the fill point just below the pump, and run cold water until there are no bubbles passing the sight gauge. Our plumber has suggested an automatic supply for this.

Maintenance

Particle filters in the inlets to the tap boiler and both tempering/mixing valves need to be cleaned annually, the latter by removing the fitting gland, which is not a good design.

The Zilmet pressure storage tank needs its quiescent air pressure checked annually, and the whole tank replaced every five years. Pressure cylinders on my Citroen last indefinitely, with re-gassing, so we’ll see. The system needs to be de-pressured for accurate pressure checks.

The solar collector array needs to be hosed periodically to remove leaves.

Costs

Our gas costs about $730 for 550 litres per year, but my urban mate pays a fraction of our price! We really only use significant gas when we have guests, then it goes through the litres when the large boiler is doing a lot of the home heating. We average about 66 mjoules of gas per day in winter, and as little as 19 at other times. The Elgas truck doesn’t come from October to late April. In 2010 we used half the gas of 2009, mainly due to better windows and remembering to keep bedroom doors closed. We will get further significant reductions when our window conversions and internal glass partition are finished.

Total changeover cost, including towel rail and some bathroom alterations, was about $11,500 against an estimated $17,000. The local shire gave us a rebate of $250 and we received another $6900 in rebates. If hydronic slab heating was built into a new home, it may not be any more than other hot water and heating systems. Our 44 RECs were not sold because the supplier did not have an approved system with the tank size we used, so we missed out on around $1500. That’s a little plus for the environment as energy companies had to find an extra 44 RECs somewhere else.

Changed family habits

The dog is often asleep on the hottest sections of the hydronic loop, always in doorways or on the top of stairs. The cats love the laundry benches in winter.

To minimise the generation of greenhouse gas and gas bills we use most of our hot water first thing in the morning, giving the solar array the first opportunity to recover hot water lost. We built a wooden, pull-down rack below the laundry ceiling which now dries much of our cold weather washing.

We need to shut off the hydronic valve when spring is well-entrenched and must remember to open it when the first cool weather is predicted after Easter.

What next?

We are part-way through replacing most open-plan area windows with double glazing, with low U and SHGC value glass and argon gas in the space.

At the moment glaziers are installing a glass, openable air barrier at the top of the living area. This will zone the home into separate living and entertaining zones, reducing wood demands and cold air currents up the kitchen.
Stopping heat escaping is next. After a government-funded home assessment, this air entrapment work was to be financed by the now defunct Green Loans scheme. Another task is resealing all doors, and chasing air leaks along the brick-ceiling interfaces throughout the living spaces and external walls. This is to stop bushfire embers and smoke ingress; the home is to be a refuge as we’ve spent a lot of money on a 10-hour fire sprinkler system for all buildings.

I’m also planning to have the roof re-pointed; it’s amazing how much heat escapes from the fabric of the cathedral ceiling when you remove a capping tile on a cold day.

Much of the living room slab could be heated, in cooler weather, by direct sunlight, and possible when we replace dark green fibreglass on the pergola outside with clear sheets and retractable shade cloth.

I’d like an automatic system to over-ride the pump control in the main gas boiler, so the rail can be heated when the slab hydronics are off. This will probably involve some extra 240v relays to override the pump’s under-temperature and gas supply controls, which stop the pump when the hydronics are not on.

Due to firebox corrosion we will soon replace the wood heater. The next one will have a wet-back for more hydronic capability.

Suppliers

Green-accredited plumbers—Baw Baw Plumbing, Buln Buln East

Solar equipment suppliers—Phazer, Warragul

Glaziers—Walkies’s windows and glazing, and Warragul glass and glazing

Flue heat exchanger, gas room heater—Cosy heaters, Warragul

Monitoring thermometers—Dahlsens, Warragul

Fire protection system—The Farm Depot, Warragul

Gas heater installation—West Gippsland gas services, Warragul

When Wayne, an architect, decided to design and build his own home, it was only ever going to be constructed from mudbrick. “Mudbrick is such an inviting natural organic medium and creates a pleasant space to be within. All the mudbrick homes I visited at the time I lived in Eltham had a certain feel.”

The design took a twist though. The most striking element here is the radical floor plan and curved ridgeline of this modern mudbrick house, with Wayne noting Gaudi and the Frank Gehry designed Guggenheim museum in Bilbao as inspirations. “It’s like a big bird laying out a wing each side of the central living zone,” says Wayne, quite an achievement for an owner-built property.

The right site

Wayne and his wife Helen searched for an elevated north-facing site to allow for the best solar access possible. They came across “a natural spot” on Melbourne’s semi-rural north-east fringe. Today their passive solar residence nestles high upon a natural ridge overlooking folding green valleys towards the Kinglake National Park, blending perfectly with the surrounding native bushland.

The property had to complement its surrounds as much as possible, hence the low-embodied energy choice of mudbrick. “We wanted to create a sustainable low-maintenance house which blends into its natural bushland environment using natural materials wherever possible and internally to achieve a light, warm, welcoming atmosphere.” It also “had to look to the future” in terms of liveability as they got older. For this reason they opted for a single-level dwelling, having come from a two-level home with plenty of stairs in Eltham.

Inspirational design

With plans to build the home themselves the design had to be low fuss. Elements such as linings, fascia boards, ceilings, skirtings, architraves and cornices were left out, helping reduce labour and costs for materials. Eaves were incorporated into the distinctive and undulating roof, which seems to naturally flow down on the sides to shield living areas from summer sun. Leaving out the internal trimmings also allows the simple and earthy combination of mudbrick, timber and stone to stand out, with the lines much simpler and cleaner.

Read the full article in ReNew 116

But what if there was a building material that could be used like concrete, but was light, strong, flexible, carbon neutral and could be produced almost anywhere? Well, there is, and it’s derived from the hemp plant.

Hemp has become notorious for its use as a drug, but low-THC (less than 0.03%) hemp called industrial hemp is now being grown in many countries throughout the world. Australia has been slow to legalise industrial hemp farming until recently. Industrial hemp is an excellent agricultural crop, taking 14 weeks to grow for maximum crop rotation, uses little pesticides and will revitalise poor soils. Industrial hemp is finding many uses, including clothing and other fabrics, rope and as a replacement for glass fibre in reinforced plastics. It is the outer fibrous sheath of the hemp plant stem that is used for these purposes, but it’s the inner core, often called hurd or shiv, that is of most interest. Sixty per cent of the hemp plant is hurd which often is deemed waste material and either burnt or used as animal bedding. Using it as aggregate in hempcrete better utilises this byproduct, adding value to a ‘waste’ material.

Hemp hurd is unique in that, when mixed with lime and water (plus sand, cement and other optional additives if desired), over time, it undergoes a chemical reaction that converts it into a concrete like material. In effect, the hemp hurd petrifies, due to the very high silica content of the hemp. This is why hemp has been successful in binding with lime in lieu of other agricultural stalks such as straw and flax. This petrification process occurs over the lifetime of the building through the carbonation of lime and is estimated to ultimately absorb over 200kg of CO2 per square metre of wall.

Advantages of hempcrete
However, unlike concrete, hempcrete, as it has become known, is non-structural, lightweight (around 15% to 20% the weight of concrete), flexible (so it resists earthquake damage and needs no reinforcing), is fire resistant, termite and rodent resistant and actually locks up more carbon than is required to make it, making it carbon negative. It is cast like concrete and is easy to work and can be poured onsite or prefabricated into bricks and blocks, or indeed into almost any shape. Hempcrete is also a good insulator, and has a long thermal lag time, so it can assist in keeping buildings thermally stable without the need for much, if any, heating and cooling, provided the rest of the building is designed appropriately. Published technical literature from the UK shows a 300mm hempcrete wall to have an R-value of 4.2 and if used in between floor joists as insulation, will achieve an R-value of 4.0 for 200mm thickness. Hempcrete, being cast in position, is also highly draughtproof which stops heat from entering or leaving the building. Having good airtightness, once the room is at a comfortable level, there is little need to continually run heating or cooling to maintain that comfort.

While hempcrete is a good insulator, it is also water resistant yet allows air to permeate through it, so buildings made with hempcrete walls will actually breathe, improving air quality and reducing dampness buildup. For this reason, hempcrete walls should not be sealed with non-permeable paints or cementitious renders.

There are two main problems. Firstly, heat is lost by direct radiation—warm objects inside the room radiate heat, which passes straight through the window glass to the outside.

Secondly, warm air is rapidly cooled against the glass, falling to the floor to be replaced by more warm air. This is called a convective current and it can literally suck heat out of a room as fast as you can add it. For example, if you have ducted heating, the outlets are often directly under or above the windows—this dramatically increases heat loss by increasing the temperature differential and breaking up the air layer on the inside of the window. Installing deflectors on the heating vents (around $10 each) deflects the hot air away from the window, saving up to 20% on heating costs.

Insulate those windows
Windows can be insulated in a number of ways. Covering them with thick curtains or using roller or vertical blinds is a good place to start, but they must have pelmets at the top to prevent convective currents circulating, otherwise they will do very little. However, this means that the windows are only insulated when you can’t see out of them, so you can have a well-insulated house, or enjoy your view, but not both. If you find pelmets ugly or impractical, then you may be able to fit a strip of wood or other material between the top of the window frame and the curtain rail or track.

Pleated blinds (such as the double layered Luxaflex Duettes) can seal well at the top because they can be mounted against the window frame.
External roller shutters are an alternative to curtains or blinds, but they also have the problem that once in place, they let in no light.

The ideal solution is to improve the insulating properties of the glass itself.

When Professor Rob Adams, Director of City Design for the City of Melbourne, won a prize several years ago, he wanted the money to go towards a new interactive architecture project. Regional Arts Victoria, in collaboration with the City of Melbourne’s ArtPlay team, had an idea that triggered Adams’ imagination, one that could teach children the fundamentals of sustainability.

Eco-Cubby, now in its third year, teams architects with primary schools to plan a cubby house together. Adams says Eco-Cubby’s charm is in the hands-on learning process: “It’s about communication, working together, mathematics—what’s soft and bends, what’s hard and doesn’t.”

There’s an agenda here, after all, cubby houses have traditionally been places of play, not formal education, with the biggest reference to sustainability being the hard rubbish collection that the materials were collected from. However, incorporating smart cubby house design into the school curriculum is an interactive way to teach the basics of passive solar design and, from the look of it, is lots of fun.

Architect and school

Architect Lisa Brennan worked with grade four students at Yarra Road Primary School last year. Accustomed to working in her own practice and as a lecturer at Melbourne University, this was the first time her expertise was brought to younger students. The school was already advanced in environmental education, and cubby house design, with a treed area called the Sanctuary being a place for students to build their own cubby houses with found objects such as branches, rocks or discarded timber. The first class involved Lisa watching how the children play in the Sanctuary, where they have their own currency, trading in gum nuts.

Next, Lisa and the students pondered big questions such as where to locate the cubby? How to build it? And who will use it? Four possible sites were selected with students assessing each one according to size, view, northern orientation, current use, whether it is flat or sloped, treed, and a general feeling as to whether that site was where they’d want their cubby house.

A tranquil spot called the frog bog was selected over others such as the basketball court and oval. Over around a dozen sessions, Lisa and the students measured the area, drew a site plan, and discussed and workshopped ideas on sustainability and design including features that their cubby would include, building materials, and how to build the final design.

Students split into four groups to translate their drawings and ideas into a model; one to build the model, one for environmental considerations, another group to make the plasticine people that would be included in the model, and the final group to document the project.
The final dream cubby house model looks ideally suited to outdoor living, with lots of open windows and garden play area. The rainwater tank is made from a box and the pipe going from the roof to the tank is a drinking straw. Importantly the roof is sloping to ensure the solar panels get a good hit of sunshine every day. The plasticine people are made to scale and dressed in purple to replicate the student’s uniform.

Eco-cubby at festival

Models from last year’s participating schools were exhibited at ArtPlay in Melbourne as part of the Sustainable Living Festival in February. Geelong East Primary School added a wind turbine to their cubby house, while the water conservation message has remained strong post-drought, with all models including rainwater tanks; one of the more imaginative tanks was made from an old plastic wine glass more commonly used at picnics.

Geelong East Primary School noted that they learnt about renewable versus non-renewable energy sources, climate conditions, passive heating and cooling and orientation. Their clever design includes a main structure which is the winter cubby, where it’s warmer inside thanks to thermal mass capturing the sun. Underneath, accessed by ladders, is the shaded summer cubby, a place benefited by cooling breezes.

Hard to build
These imaginative models are one step from reality though: the building process. Regional Arts Victoria’s Emily Atkins says that only two cubby houses have been built, with the  emphasis being on the design and learning phase rather than a finished structure. While the backyard cubby house is relatively cheap to build, especially when out of the eye of authorities, these Eco-Cubby designs are subject to more stringent assessments when built at schools. “Surveying and building costs can be as much as $40,000,” she says, with the main expense being surveying.

Understandably, to build one of these dream cubbies requires some serious fundraising, often beyond what a cake or plant stall can deliver. The University of Melbourne Early Learning Centre opened their Eco-Cubby last spring, a recycled timber and mud brick structure that hit a bureaucratic snag or two during the building process. The kindergarten students made their own mud bricks with their parents, only to be told that the mud bricks were an irregular size, and couldn’t be used to build. Pre-made mud bricks were bought (which apparently weren’t that much different in size) and the old mud bricks used in the garden instead. The second cubby house, a chook shed cubby, is at Barham Primary School near Kerang, with plans for another at the Olive Phillips Kindergarten this year.

Emily says the results with just paper, cardboard, tins and pipe cleaners have been abstract enough. “They’ve displayed amazing ideas, especially in regards to sustainability.” She says that hearing kids say ‘it has to face north so that it warms the house and that’s passive ecology’ is proof enough of the program’s success.

Holmesglen carpentry students have built transportable homes, cabins, club houses, granny flats and other small buildings for customers mainly in country areas around Melbourne for years. Students from other disciplines undertake plastering and tiling work. Professional trades people perform the electrical, plumbing, painting and kitchen installation, which for this house were completed prior to transportation.

I discovered these student-built houses more than 10 years ago when I attended a short course in woodwork at Holmesglen. The instructor gave a tour around the school and took the class through a very impressive sports clubhouse and small home that were being built at the time. When the opportunity arose in May last year to buy a small block of land, I rang Holmesglen first to ensure they could build me a house.

My block is in the coastal hamlet of Sandy Point near Wilson’s Promontory in Victoria, where I love to go windsurfing on the adjacent Shallow Inlet. Timing was tight. The house needed to be built by the end of the 2009 school year as it was anticipated students would be busy rebuilding homes to replace some of those lost in the Black Saturday bushfires. Yet at the time the Victorian bushfire building regulations were being redeveloped and in a state of flux. Bob Collins, a local Fish Creek draftsman, spent many hours along with Peter McMahon, Training Manager in the School of Carpentry and project manager on this build, trying to understand the new regulations in order to complete the plans to the required specifications.

Read the full article in ReNew 111