Rear two-storey extension

Sustainable renovation

This solar passive renovation uses the floor plan, foundations and timber frame of an original beach cottage as the base for a two-storey addition.

Photo courtesy Living Green Designer Homes


Philip O’Brien

A feature of the Australian housing boom of the past decade has been the popularity of the ‘knock-down and rebuild’. It’s an option which allows homeowners to remain in familiar surroundings and to avoid the costs of stamp duty and moving house.

But a more environmentally-friendly choice is to renovate rather than demolish an existing home, according to builder Craig Riddle, of Living Green Designer Homes on the NSW Central Coast. And he’s done just that with a beach cottage which recently won the 2018 HIA GreenSmart Australian Renovation/Addition Project award.

The original cottage in MacMasters Beach on the Central Coast, was a much-loved home which had been in the one family for 50 years. However a new generation needed a residence with more room but one which was also comfortable and energy-efficient.

‘When I first saw the house, I knew instantly that it was not a knock-down job,’ Craig says. ‘It had too much character and I could see what it meant to the family emotionally.’

Older houses, such as these, are often criticised for their poor orientation and insulation, he explains.

The original cottage in MacMasters Beach was a much-loved home which had been in the one family for 50 years

‘But, in many ways, older buildings set an example for us today because the only way to create sustainable housing is to use less and to use it wisely. They built houses small then, they built them without using a lot of energy and transport and without all the items that need further maintenance such as air conditioners, inverters and modems.’

So, his solution was a renovation which used the floor plan, foundations and timber frame of the original cottage to which he added a two-storey extension at the rear.

‘We had to replace both roof and ceiling because the originals weren’t structurally sound,’ Craig says. ‘But the existing framework and cypress pine floors were able to be retained which meant that we could install new roofing, cladding and windows to match the extension.’

The result is a spacious and pleasant home providing year-round comfort, created with a focus on sustainability and solar passive design.

The HIA judges were impressed, noting that by retaining most of the existing home and following the slope of the property, the extended home is resource-conscious with minimal interference to the natural drainage of the land.

Rear two-storey extension
The rear two-storey extension
Photo courtesy Living Green Designer Homes
Sustainable renovation lounge room
The home optimises natural light, warmth, cooling and airflow
Photo courtesy Living Green Designer Homes

In fact, drainage was one of the challenges that Craig faced during construction. ‘Being below the level of the road, the block suffered from stormwater erosion in heavy rain with water flowing under the old house,’ he says.

‘This required extensive drainage so that it would not flow under the extension. In addition, there were about half a dozen native banksia trees near the front door that we needed to protect and preserve. These trees became an integral part of the finished landscape design and, for the owners, are almost as important as the house itself.’

Construction of the home took only 16 weeks, Craig says. During this time he implemented many of his company’s key solar passive design principles which seek to optimise natural light, warmth, cooling and airflow, thus reducing the need for artificial lighting, heating and cooling.

Specific measures included the installation of low emissivity (low-e) glass, maximisation of the north elevation and extension of the roof eaves to provide greater shade. He also installed R2 insulation to all wall framing and R3.5 to the ceiling roof cavity as well as connecting the house to natural gas for hot water and heating.

‘You can’t buy sustainability in the form of add-on gadgets, and then continue with a lifestyle of energy waste’

‘Energy efficiency is the main solar passive design principle,’ he says. ‘I always tell clients that if we keep a home well-sealed and insulated with a good quality glass then we can access all the winter sun [coming] into the home and keep all the summer sun out.’

In addition, Craig says that the clients set particular construction conditions. They specified the use of low volatile organic compounds (VOC) in paints, carpets and furnishings. They were also concerned about electromagnetic fields (EMF) in the house.

‘To alleviate these worries, we ensured that all wiring and modems were stored at the point furthest away from sleeping/living areas. Some were placed under split-level stairs, others in the furthest away cupboards.’

Craig has been a builder since 1983. As an accredited HIA GreenSmart professional he was especially proud to add this award to the many which Living Green Designer Homes has won since it was established in 2007.

‘Our business is to design and build sustainable housing. Every award is special but this one, being both a renovation and an addition, means more because there was a degree of difficulty in getting the old to meet the new,’ he says.

Growing up as the son of a builder on the NSW Central Coast, he says that he has always been interested in sustainable construction.

Sustainable renovation kitchen Photo courtesy Living Green Designer Homes
Rear two-storey extension Photo courtesy Living Green Designer Homes

‘What I have realised about earlier decades – the time in which this original cottage was erected – is that building then was quite sustainable and environment-friendly. There was no internet to source materials from far away and only limited transport infrastructure. So, builders tended to source locally: local hardwoods, stone and other materials. In many ways we need to get back to that.

‘I’ve always been concerned about waste in the building process, everything from time and energy to the use of materials and the power required to run a home. You can’t buy sustainability in the form of add-on gadgets, and then continue with a lifestyle of energy waste. If you want true sustainability then don’t sell the house you’re in to buy a new one; stay where you are and upgrade. There’s a responsibility on all homeowners to reduce their ecological footprint.’

Not surprisingly, the clients were delighted with the finished home and, after living in it for some 18 months, told Craig that they have fallen in love with it all over again.

‘I’m humbled by comments such as these,’ he says. ‘After all the work we did on the house, it’s very gratifying to know.’

At a glance

Construction time: 16 weeks
Project size (renovation and addition): 325 square metres
Project cost: $2,290 per square metre
Roofing and guttering: Colorbond
Wall cladding: James Hardie Scyon Stria and Scyon Axon
Paint (internal and external): Taubmans
Locks and door hardware: Lane
Wall frames: Plantation pine


• Kitchen and island benchtop– 40mm Caesarstone
• Cupboard doors – Laminex Natural White
• Overhead cupboards – Laminex Sublime Teak


• R2.0 wall insulation batts to external walls
• R1.5 sub-floor
• R3.5 ceiling insulation batts

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