is the downstairs ceiling height the same throughout? which direction does the block slope? please show position of all windows, the stairs would be better in a more central location but all measurements need to be confirmed and you should check with council to find out what rooms can be included downstairs ... i wonder if removing bed 4 walls would create better connection to the rear deck and pool but no specific suggestions can be made until the existing building is better understood ..

The measurements may be off - this is only the real estate floorplan. The top and bottom of the house are the same widths all round - like a brick box house (photo). Measurement confirm the stairs will fit where planned but am open to other ideas.
There is a slight slope from the front to the back of the home with a 1.5cm difference in height. We will get council approval for the garage but internally I was not too worried. It is classes as garage/storage. It will be for our long term use.
There is a big door from the kitchen to the deck so think that access will be fine (photo).

Hi, where to you want the new living space to enter into the backyard. when looking at photo at rear of house -Via the existing door area to right of steps. Or under the deck to the left of stairs? Either way add double sliding doors or French doors to this access point. Where is your clothesline outside. Laundry door should be convenient. Would you like a laundry shoot from upstairs? This doesn’t have to end in laundry, could be into a cupboard. Or I’ve always wanted a dumb waiter

without the legal headroom downstairs you can improve the feeling of height by cladding under the floor between the exposes rafters, hiding all the pipes and wires and painting the new ceiling white but my main suggestion would be to sacrifice the small upstairs bedroom to create a bigger kitchen, better connection to the deck, better stairs location, easier access up and down and more space for the rumpus and bedrooms downstairs...more precise details would depend on how you want to use the rooms and major cost of rearranging plumbing in an existing concrete floor so i've left the downstairs plumbing intact but if the downstairs narrow store room could be opened up you might squeeze in a reasonable sized garage without having a major extension out the front but always depends on accurate dimensions and structural restrictions but i've left the small supporting posts to show how they could be fitted into or replaced by new dividing walls and extra light could be provided in windowless spaces with solar skylights

Thank you Kate for your comment. The french doors are a great idea. I think we will keep both exits as one is out to the clothesline (from the laundry) and the other will be good for the entertaining end. Better to have another fire exit up our sleeve anyway!
I found this photo online - love the doors and the colour scheme (it was originally orange brick too!).
There is a laundry chute. It can be see in the last photo of my original post next to the fridge. I was going to dissolve it when putting in a cupboard in that bedroom but guess there is no harm in leaving it there or turning it into a lazy waiter. I agree they are cool! It would save me carrying all the laundry upstairs too!

Thank you very much oklouise!!!
What great, thoughtful plans! My husband and I really like these designs. The fact that you have taken existing support poles, plumbing, etc into consideration is just fantastic too.
I had originally thought about putting the stairs where you have suggested but hubby was conscious of losing a ‘legal height’ bedroom to stairs. Your plans have shown us that it really is the best option and allows for better room planning downstairs.
Your suggestions for cladding the downstairs ceiling is great and definitely something we will do.
I am so very appreciative (and in awe) of your thoughtful design and quick response. Thank you so much!

Oklouise has chosen a great position for the stairs by using that small bedroom this will also allow much needed space for the wall of pantry cabinets in the kitchen.

I have added some more ideas for you to consider, I think that your existing laundry is a perfect space for a bedroom with french doors opening to the outdoor alfresco garden and pool. This downstairs space could be used for teenagers, Parents, Air B&B, even with different ceiling heights. I had an aunt that did this in her downstairs smaller space, the lower ceiling area was used for a bedroom and study both had windows and were wonderful. cheers

Thank you Siriuskey for your design. I’m so appreciative of all the ideas. I do like that there is room for a pool table and the double doors to the bedroom would be lovely.
We have two kids and a mother-in-law that visits from overseas so the bedroom and ensuite for her would be great. She may end up staying long term in the future.
Light will be the most important in making these areas feel bigger than they are so some windows in the rooms under the front porch might be good.

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.

another option to consider would be an extension of the rear deck to enclose the rear stairs and create a sheltered stair well without sacrificing any internal space for for stairs and potentially rearrange the front steps (without losing bedroom window) to add an extra room above the front porch so that the old study can be used for better connection to the rear deck and perhaps create a separate lounge (or extra bedroom) out of the old living area

Always a good idea to live in a new home for awhile to get the feel of it, and seeing that you are planning to do the reno in stages that would work. Do you have any photos with views of the front of the house. cheers

Thanks oklouise. Again, some great food for thought. That could work with the front area and might explore this further with the builder.
Siriskey - they aren’t brilliant photos but attached are a couple showing the front of the house.

it comes down to balancing outcomes against the numbers....by the time you muck around with internal changes on existing upper level, stairs, windows, not to mention potential issues of non-compliance, it may prove a cleaner/better option/outcome to develop additional spaces under the deck with proper ceiling heights and better light quality.......seriously we've done a bunch of these similalr types of 1960's 2 storey brick monsters over the past decade where you're dealing with managing disconnect between main living on upper and external spaces and it's remarkable how the numbers add up.....and as I have mentioned on here time and time again, it can be false economy trying to rearrange within existing footprint with consideration to the opportunity of alternative solutions that minimises (arguably compromised) renovations (a more resourceful strategy) and distribute budget into more effective, appealing & higher value adding extended space...

There's nothing worse than dungeon-like space...it ALL about the light and sense of space when it comes to developing/designing areas that appeal......

All I'm saying is make sure you consider various options and crunch the numbers properly and if you can;t do that confidently on your own seek Pro assistance in this regard

Best of luck!

PD :)