Plan everything & get quotes for all elements, electric, plumbing, insulation, sound proofing... strongly consider solar passive, energy rating, double glassing, water recycling, ongoing maintenance, organic gardens, shrubs, fruit trees, fences (style & cost). Uni Queensland has some young engineers developing Tiny houses plans & fabrication so Google them. Investing in an Owner builders license would be a good insightful investment. Know the costs right down to council fees before you commit.

The approx 60sqm space doesn't include the stairs and is only one bedroom. I haven't decided on laundry as it could be possible to share the existing one which opens off the existing garage. The external stairs would be adjacent to the side door off the garage which is next to the laundry. I don't already have plans but have been playing around with a floor plan myself. That is why I'd like a little input on the design possibilities. Using the upstairs area myself might be possible one day, but not for the foreseeable future as I have two dogs and need the yard. I also have a number of interests for which I need my existing space. Additionally I don't want a whole houseful of tenants with which I would have to cohabit. Ideally it will just be one person. Thank you for your suggestions re the MyAgedCare Program, but I have just had the experience of that process with my own mother. The waiting lists for care are very long and even just getting assessed takes a long time. Last time I heard there were 90,000 people on the waiting list and some 16,000 died in 2018/19 while waiting. Additionally, you only get a few hours assistance a week, there is no live in or on call help and a lot of the money gets eaten up in admin costs. It doesn't hold a lot of appeal for me in it's current form. Hopefully the Royal Commission will result in some improvements and it may provide a better service by the time I might be in need of it. I have considered buying another house on a bigger block where I could put a granny flat , but haven't found anything suitable. Most houses which offer this possibility are unrenovated so I would have to do a full reno on the house as well as build the granny flat. When you consider the costs and disruption involved in that, plus the costs of selling and buying and moving, it just seems all too hard. That's why I've come back to this option.

As we won't be staying there for long periods of time at once we do have limited outside area. Only the pathway from the footpath up the side of the carport and granny flat. There is currently a garage (connected to the house) and the carport. As part of this build there will also be another double carport. So, the house and granny flat will have 2 car spots each, tandem parking. The house is rented to family at the moment. But trying to make the granny flat as separate as possible in case that changes in the future. The granny flat will be off the ground (not concrete slab) but not quite as high as the house (I believe) but high enough to get the right drop for the plumbing.

is the garage attached and part of the original house or a separate building or extension?...we need to see a site plan showing all buildings and a plan of the whole house showing room sizes, doors, garage doors, windows and location of existing plumbing.. ..what is the shape of the whole roof (Google earth view and some photos would help) and what are the roof, walls and floor (of the house and the garage) built out of?...is the garage at a different floor and/or ceiling level than the house, how will you use existing bedrooms and do you need a new carport/garage? BUT before you make too many plans you should check with local council to clarify what will be needed for the conversion because a garage is not usually built to be suitable for bedrooms or living areas and 10m x 4m is probably big enough for 2 beds and a bath or 2 beds and a small living area but not for 2 beds + bath + living area