The mezzanine and storage spaces. Next to the mezzanine the builder installed a little door for us to give us access into the roof space. As the kids are using the mezzanine as a chill out area to watch TV play video games the storage now holds their board games, art and craft etc. The girls painted the walls to brighten it up. As the ducted system didn't work too well at the front of apartment we had to install a split system AC to cool down the study and the two front bedrooms.

with a lot of helpers crowding around to help i suggest that the new kitchen needs to be zoned for tasks and be open plan without a separate pantry...this rough idea has a central island about 2m x 3m surrounding the column and walkways approx 1.5 m between counters, subject to available space with the column the island has mostly underbench drawers for pantry food storage, crockery and cutlery and the counter is for food preparation, serving, sorting and distributing clean and dirty cookware and bags of groceries etc and has a small extra sink but no more than a couple of stools to keep the workers moving!!..Subject to suitable access the central space under the big island (would be about 60cms wide, 90cm tall and almost 3m long!) would be ideal to store folding tables and chairs and "christmas" supplie in wheeled storage crates or pull out kitchen island trolley..There's a full size fridge and freezer as well as an underbench drawer fridge next to the tea, coffee & toast area,with cup glasses and breakfast supplies in the overhead cabinets..twin dishwashers with double sinks, hot cold water dispensers, pull out garbage bins and a modern insinkerator or compost disposal in the sink area..the cooktop and food prep area is on both sides of the corner with big appliances underneath, and serving plates and casserole dishes etc overhead..The base cabinets should be deeper than normal for more generous counters and giant cooking equipment and appliances stored underneath and to have shallow splashback shelves for herbs,oils, sauces etc and there's a stacked wall oven and microwave and a stacked wall oven with warming drawer and vertical shelves above the ovens to stand up trays, racks, cake and pizza trays and drawers below the ovens for saucepans and baking dishes...decorative finishes and fine details need to be determined by the resident cook for personal taste and everyday comfort

You need to research the steel (not aluminium) window manufacturers in your area. As steel is stronger than timber and aluminium you can use a smaller cross-section for the door frame to get the slim line look. However steel framed windows and doors do transmit temperature as metals conduct heat well. Beautiful and expensive, but not thermally efficient. https://www.steelwindowdesign.com.au/projectgallery#/private-residence-in-toorak/ Best of luck, Dr Retro of Dr Retro House Calls

HI All - for some reason my lengthy reply a few minutes ago was deleted :-(. I put so much thought into it! So here it goes again. Basically a big thank you to you Houzzers. MB your subfloor ventilation sounds great and Im glad it's fixing the problem so simply. The reason why Im trying for a whirligig solution is that I favour a passive system, however if it doesn't work I'll look into what you suggest Siriuskey - yes to some kind of kit. I've already contacted a guy on Gumtree selling grannykit frames - he says for something to my specifications would be about $4000 for the steel frame alone. Would need to check engineering details - and the liveable sheds you've linked me to seem to have that all checked. Although getting a local Chippie to frame it all up on site - as Twos Co suggests - is probably the most economical option Two's Co - thanks for the feedback and the excellent checklist of processes. I've covered most of the concerns though - I've got the DA based on my own flimsy plans. Because it's relatively small, I was going to work with the builder directly and over-engineer it. I've since engaged an architect to do some handsketches and draft specs, which will be signed off by a structural engineer. It's basically a portal frame independent structure, with a 3 degree pitch skillion roof. The house was rewired and the wires you can see are non-live looms waiting for the extension! The sewer is not connected and that part was never plumbed in. There's good rear lane access, but for the purposes of getting concrete in, I'll most likely get a concrete pump from the front of the house - for $180 per hour they will save time and make the concreting much easier. The existing trench I got dug in because I had an excavator on site installing those lovely large concrete blocks you can see, for the retaining wall (500kg each). But that was 7 weeks ago, and the excavation has got too large, and I worked out for a very similar cost I can make the extension 1m wider, so why not. The existing trench I can fill in with the demolition rubble, compact, and filled with any fill waste. Two's Company, I'm on the fence about removing the existing Bedroom 3. If I thought it wouldn't add to the costs too much, I'd do it. One advantage is that I could then make the whole 9m long extension (Option 2) around 150 - 300mm higher, (ie a step up from the existing house) and thus avoid too much excavation and a potential pond. To answer your question about damp and moisture, the whole house is facing a hill with 7 degree slope, and fixing this has been the main aim of the retaining wall, however the runoff is only likely to increase in coming years. anyway here are a few photos. The site is still so messy because the demolition only happened 2 days ago - Im still tidying up....