For those looking to build a sustainable granny flat here’s an email exchange which may assist:

Good afternoon Michael,
The tour of your house, and of your knowledge, last Saturday was quite enlightening – thanks. I am in the situation of having a granny flat built on the property I share with my son & family, at Burraneer (near Cronulla). We’ve given the job to a company called Granny Flat Approvals, link below. At this stage the proposal has not yet gone for DA because we’re awaiting council approval to remove 3 trees…so there would still be room to make changes.
The dwelling will be 2-bedroom – 60m2. At this stage it will be brick/rendered with a colorbond (double) skillion roof.
The orientation is north/south. I desire good lighting and I think the windows will achieve that, along with a strip window (above the living area) created by the double skillion roof.
I wanted gas appliances, however we are interested in solar power and as my son & family have the bigger & higher house with more sun exposure, we thought to install solar on their house, and power mine using that source (rather than put solar panels on my place which is smaller and more shaded.
Are there some suggestions you would make? I know that is a broad question…! I haven’t had the chance to immerse myself in your book, sustainable house, as I realise there may be some answers in that ????
Your thoughts and suggestions will be most appreciated. Thanks for the opportunity to pick your brain.

Best regards,
Miriam Sorensen

To which I replied:

Hi Miriam, a few suggestions:
Write to Granny Flat Approvals asking them to give you a design which will:

Most likely not require summer cooling and winter heating using Polyair insulation in the floors, walls and roof (Performa 7 -www.reflectiveinsulation.com…) + color bond Thermatec which reflects heat;
Include a connection to the solar panels on your roof and or the main house roof (email Richard Keetley of Australia Wide Solar for a a quote: Richard Keetley <Richard@awsolar.com.au>
Store at least 10,000 litres in slimline tanks and use this for all the granny flat needs – they can be in say, 3 x 3,000 litre tanks – from Tankworks at Blacktown: tankworks.com…
Allow for low level top up of mains water – Tankworks can design and provide this solution for you
Plumb two lines to the toilet and clothes washing machine in which greywater or treated blackwater may be used at some future time
Don’t use tiles in the kitchen or bathroom – too polluting, too slippery and dangerous, hold fungus and mould, too costly and increase the build time – for design and materials examples see: sustainablehouse.com…
Specify ONLY Australian timbers and recycled timbers – no imported timbers in particular from Malaysia and Indonesia as they are harvested by corrupt generals killing local tribespeople and wildlife and causing the single biggest pollution from timber harvesting on Earth
Double glazing on all windows

And you may wish to come to the information night at my place about solar PV and battery storage.

Do read my book asap

Good luck to those reading,
M