realising that you did not mean to have one long narrow room but i think we all recommend an L shaped extension (not necessarily my suggested plan) because it will be much more cost effective than removing the whole back wall of the house and replacing all the separate ceilings and windows and not achieving much more than an enlarged bathroom, bedroom and small ensuite..the Lshape extension of similar sq m would create a more comfortable floorplan for the whole house with a simpler extension that also has the potential for a deck or alfesco to enjoy the bush view..photos of the roof and back of the house and measurements of the distance to the side and back fences and location of the pipes you mentioned and rough measurements of the bathroom, laundry, wardrobes and short hallways would allow a much more detailed floorplan to help invite more suggestions

Thank you oklouise. That’s very nice of you to offer. We have had a builder provide some advice around some of the structural walls, etc - one of which is that little storage area under the new ensuite. We had explored removing that to make it a double garage but it really would blow out costs and advice was the extended double garage would probably be cheaper. I do very much see your point about spending money on legal-height extra room though - makes complete sense. I would like to do something with the front porch - with the deck and under deck areas, I don’t foresee us using the porch much at all. The exterior house walls are structural though so again, it could be costly to move. There is also a window into Bed2 that opens onto the porch so this would either have to be filled in (there is another one but not sure we want to decrease light or breeze) or built around. I did want to close in the screen door to the living room and build in a bit but it could be a lot of expense for perhaps a metre wide gain!!? I wasn’t sure how we were going to use the storage under the new ensuite but from your design, I think that garage area would be good as the kids play room and that area as their toy/games storage. With family overseas, we usually travel once a year and have luggage for all of us so happy to have just an extra storage room (such as that under the porch). We only really need 4 bedrooms so I still think sacrificing the upstairs study is probably still the best use of space. We were going to do the reno in two stages - garage, ensuite and stairs before we moved in and then downstairs afterwards. Perhaps we hold off on the stairs to live in and feel first.

siriuskey, Yes, the courtyard is open to the sky (no roof over it), I assume this is what you mean by double story. Ref. below photos, I would love to get this look, especially the first and last photo, where you can see family living space from the first floor. I can't achieve this in my plan as it eats a lot of floor space upstairs. The referred plan (photos) has a very big void combining staircase, hallway and dining area. I know it is not easy with cooling and heating when you have such a big void. So, I explored a few ideas (with my limited knowledge on this topic) before achieving the current floorplan. I have also thought about, in my current plan, extending the void on the staircase to the dining area (it is more like L shape) but i wasn't sure if that makes any difference. keen to hear your thoughts.

As OKL it's a bit artistic licence without all information In my experience it's important to keep the charm of the original building Fireplace ceilings and trims etc. The following maintains part of the driveway which is also important and still allows a 900 access to the rear, this is if your building code allows The Master bed, Ensuite WIR and laundry extension would be done in timer with the roof to match the current colourbond. Exterior photo of property is via the link I posted above which shows how tight things are.. Going up at the rear over the Colourbond section could also be considered, Ie second story. with a view out over the garden.