July 18, 2011

Building a green house in Coogee

Building a house offers a great opportunity to make things better than what we had experienced living in Australia over the last 15 years. After all the cold and draughty winters in shockingly insulated homes and hot and sweaty summers in badly ventilated and insulated flats and houses we thought: let’s get a house which offers us comfort all year around. Sydney is such an ideal place to live in a passive home. It’s not too cold in winter and summers are quite bearable, as we always get the cool breeze, the southerly, at night to cool things down. We wanted to capitalize on that and live with what this climate has to offer and build a house which easily balances the temperatures to give us a comfortable living space without the need of air-conditioners or excessive heating.

Warm in winter cool in summer

To get a passive house, we had to orientate the house towards the northern sun and insulate the walls and roof well. The insulation is installed on the outside of the house, it has an R value of 4 and it protects the concrete walls from the summer heat, so it doesn’t heat up on the inside. The concrete walls are not covered from the inside, so that during winter, when the sun is nice and low she heats the inside of the house, the walls and the concrete floor. That’s our thermal mass which will give us an even warmth, spread throughout the day and night and the concrete acts as a heatsink.

One weak point in Australian homes is usually the windows.  Normally they are single glazed and not well insulated around the frames, nor are they airtight. My husband and I we both grew up in Germany and even though our winters are much colder over there, the homes are warm and cosy. Here, we have cool, but nice sunny days and it’s great outside, but the homes are often cold, draughty and uncomfortable.  Turning the gas heater on and off is a constant action during winter days and once turned off, the houses cool down quickly. The warmth just travels straight through the windows and frames . In our wonderful passive house, we’ll have double glazed uPVC windows throughout. They are not even that expensive to get, but they offer a world of difference in terms of thermal performance.  And they look great. The material used for theuPVC framesis not environmentally suspect any more, they are fully recyclable and don’t contain lead any more. The Koemmerling brand of uPVC windows offers a “green line” in all their products, so the old concerns of them being environmentally unfriendly in their production process is eliminated.  They also are very durable and don’t need any maintenance once installed. 

So many things to consider

There are many more big and small things we considered in making this house a passive, green house. The use of recycled concrete just being one  amongst a whole array of cost effective and green planning  measurements. There is even more we would like to do, but regulations in this country are very strict and often don’t help the cause. One desire we had, was to get a green roof, meaning a planted roof with low level plants. That doesn’t only look great, adds protection to the roof and helps with the insulation in a natural way, but also provides a better run-off for rainwater and adds to greening the urban landscape. But the costs have turned out to be too high, as we have to install additional balustrades for accessing the (flat) roof, as well as it is illegal to use the run-off of this clean and naturally filtered water for our rainwater tanks and the grey water cycle.

So far building this house has been a rewarding process, it’s been exciting to find different building materials to help the cause, discuss with various trades how we can best achieve our aim without breaking the bank, find new ways and get different view points and look at various construction options. It certainly is a great team effort together with our builder Cameron Rosen from Australian Living, who always considers and discusses new ideas with us, which are on the forefront of green building construction in Australia and who is open and very considered in his approach.

This blog has been written by Dorothee Babeck, the owner of the Dolphin Street home.

Read the first blog in the series: http://reduceyourfootprint.com.au/blog/reaching-for-the-stars-on-dolphin-street/

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1 comment

  • Building Green house building is most important nowdays. Very interesting article. Thanks for sharing your knowledge.

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