Yarnos I agree with Natasha. Your existing architect will have (well, should have after working on your existing design) an intimate understanding of your site, soil conditions and implications of levels on your design. He/She are in the best position (given his/her understanding of your brief and constraints) to illustrate to you how a design solution such as this can work. No one on this forum is currently in a better position than your architect to explain this to you and outline the affordability of it as an option, based on your site, your brief and your budget. You can visualise this concept by letting your architect demonstrate it for you. If they are not demonstrating it, then you have the wrong architect I'm afraid. And if you are not empowering them to use their expertise and provide design solutions for you, then you either need to get another architect, or be a better client. Architects and designers - the good ones - are creative problem solvers. They are design detectives in the art of living well. They spend their entire professional and personal lives and time studying how people live, and how to create environments (and homes) for them to support them living better - more functionally, flexibly, beautifully. The talent of a good architect/designer is invaluable in elevating your lifestyle ... of taking the 30 year mortgage you're about to wage on this bet of building a home, of taking this massive investment, and turning it into a physical building that is your heaven and haven, your place of sanctuary and inspiration. They expand your vision, interpreting both what you say, and what you don't, into a result that is beyond your imagining. That's why you hire them - because you can't do what they can, and you need them to bring your dreams into life in a way that's better than you could have ever anticipated or created yourself. As a client, you have a responsibility to brief them well, trust them to do their job, be open to their ideas, and be guided by their expertise. The not so good architects and designers are simply drawers and documenters. They 'convert' your brief, your expressed wishes and shopping list into a floor plan that fits, and can be built, but that's simply it. It's a house, not a home. It functionally will do the job, but it never reaches its full potential. And so your life in it never reaches its full potential. You unwittingly compromise, never truly aware of how different, how much better, things could have been. The catch is, you've made a massive investment, and created something that will outlast you and become someone else's home too. So the impact is generational. Your responsibility as a client to these architects and designers is to understand the difference, and ideally not work with them - not unless you can show design leadership yourself. Work out which one your architect is and make a decision. Trust them to do the job properly for you (and give them the ability to do it), or walk away and find someone else. Regards Amelia Lee Undercover Architect www.undercoverarchitect.com amelia@undercoverarchitect.com

Appreciate the thoughts and this may be a solid option elsewhere in the country but in my circumstances I don't plan to be moving from this property any time before the kids are 18. It is located in Sydney's inner west, and in a specific high school catchment I plan to take advantage of when the kids are older. Stamp duty to buy the property was close to $100k and if moving out even in ten years to a larger property; that averages $10k a year spent on stamp duty. I know 115m2 internal is tight, as is the fixed layout due to existing bedroom walls, ceiling heights, wet areas, and the like - but there has to be a way to make this work... I have read that 4 bedroom apartments should be 102m2 or bigger. I am willing to make compromises where possible but I really want to create that extra separate room "Multi-purpose room" which can double as a study/work area/kids play area/media room/ad-hoc sleeping accommodation". Paul Di Stefano: I don't think these changes essentially equate to 'rearranging a sock drawer' - this is my PPOR so I am not too concerned what other buyers want or resale value if I plan to hold the property for 10-20 years +... (any trends we design for now may well be outdated by then anyway). Many buyers highly value indoor-outdoor integration. By moving the kitchen to centre, it opens up the rear and creates indoor living->outdoor living link. If I get IKEA flatpack kitchen and DIY as much as possible - have a friend reroute the water/drainage/+his licenced electrical friend...hopefully this work would cost sub-$20k. Adding the sliding door to rear is $2.5k. Ensuite, bathroom and laundry I believe I can fitout for $10-15k all up- let's say 15k (again, tiling, raise flooring, showers/fixtures/flat pack laudnry cabinetry install all done in-house without tradies). The only thing I really need professionals for is to move the gas line in kitchen, BIR installs, stone benchtop, and maybe a few adhoc wall demo/construction/doorway moving - lets call that 10k. All up ballpark that is 47.5k? Sirius- If I go with your style plan then I lose the potential 4th bed space and have no where for relatives to stay, babysitter, nanny; etc :( Maybe it is a possibility that the main living space be used for lounge room and kitchen, we can always put dining table in the Multi-purpose room, then when that room is needed for sleeping accommodation, the dining table be moved to the side and kids can eat dinner on island bench bar; lounge or outside table... ? those doors to each side of the fireplace as you suggest - this space is very cramped outside (2.45m width) and potentially would be used to store trailer or garden shed, there is an old terrace built on zero-boundary there and they have a DA to go 2 storeys; which will shadow the whole area. This is why I planned to make the rear south corner a raised deck and try to channel house activity leading out the existing glass french door to that deck, or the rear sliding door. See photo-(my house is on the left, terrace zero boundary on right, and front on is a wooden dividing fence which on the opposite side is the driveway/1 car park and front street.

Thanks everyone for your comments so far. Some great points have been made and I'm going to take each one of the away to have a think about. In the meantime, I've asked my draftsman to provide me all the measurements to existing and proposed so I can share it here as soon as I get them. Some more info: We're located in the northern suburbs of Melbourne. Our budget is approximately around the $200k...this is so we don't over capitalise on the property. We thought about building to one boundary because we are of the thinking that we need more width to achieve the space we want. As a guesstimate, I believe the block is 12m or so wide. Each lane way is approximately 1.5m (3m combined) which only leaves us with an internal width of 9m (minus walls). We chose to explore building to the eastern boundary because existing utilities such as hot water system, ducted heating are already setup there. Moving it to the western boundary would cost $$. The eastern laneway has nice new concrete paving and allows us to more easily access it from our carport.The other reason for potentially building to the east is because we're the 2nd last house on the street (near a corner). We get a bit of traffic on our street but more so on the street parallel the western wall. I thought it would be more peaceful moving the house away from the traffic and noise rather than towards it. Also, the addition of the dining area (connected to kitchen and alfresco) will give us a bit more privacy from the street (parallel to western wall) when we're out on the alfresco/deck. Just my thinking but happy to get some further feedback. We're happy to consider keeping the current building boundary if we can achieve the design we want etc. I've attached a few pictures of the existing low ceilings towards the back of the house. The pics show the ceiling from kitchen and towards the back door (curtains are closed). The ceiling is about 2.4m and you can see the exposed beams which makes the ceiling feel even lower. I'm only 1.6m and I can touch them with my finger tips if I try... Whether it's a full knock down or increasing the height of the roof, I think it's the one thing we're about improving/removing. Hope that's some more info for everyone to go off... Thanks again for everyone who has already replied and made some great points. Cheers

Ground floor we are thinking of going with this one. I am not worried about northern sun now, as with our landscape it is bit hard to try another shape and we feel like this layout of kitchen/dining/living gives us the most usable space. We might put a tall window above the kitchen bench instead of an overhead to get more light in. I have added a hall way table at the entrance, A bigger study/office, Linen/broom/storage space, laundry has external access. For the First floor we are leaning towards this one, which gives more space and big robes in bed2 and bed 3, also a WIR for his&her. 1800mm vanity, walkin shower and bathtub, a small balcony enough to put chairs and a small coffee table, we may make the balcony a little bigger as the master bedroom is now 4x4.7m. What we think is with this configuration 3/4 people can use the family bathroom area at the same time. I am not much worried about the bed orientation, this configuration work for us, anyone buying, its big bedrooms, they can put it anyway they like. Thanks to all specially to @oklouise and @differentways who went above and beyond to draw the designs for me, we wouldve put the toilet at the bath with window as differentways. suggested, but. then its too messy with robes and bedrooms get small., We dont want any robes sticking out, a wall to wall robe will give that luxury feel. We also like @dreamer ensuite design but again i think this one gives a different feel, something out of the box, what we usually see like in hotels. Also thanks to @macyjean & @Kate some of your advices were very valid and got us rethinking a lot of stuff. And thanks to all the others who spend there time looking at the design and reading the long messages and giving there much valuable opinions, every little suggestions are important. I know its not finished yet but we are almost there, if there is anything to improve or if i miss anything please let me know. We really value your thoughts and suggestions. We are very happy this turned out this way.