An architect, a building designer or an interior designer (not an interior decorator) should be able to work with you to create a design you love and get the most out of your interior space. You (or your designer) will also likely need to consult with an engineer, or possibly a good builder, regards load bearing walls etc.

OK, a few issue here. General comment : It could be heaps better - there's nothing much exciting here. What do you see when you walk in the front door? The back of the garage door beyond the window. There is a disconnect of flow from the kitchen and the living/dining zone. To start with The plan is missing furniture (big designer fail). You'll see once that is put in whether it's working appropriately for what you want or not. I'd guess if you got a lounge onto the plan immediately you'd see that you'd be squeezed walking into the end of it trying to access the dining table and depending on the dining table proportion's likely that area is squeezed. The relationship between the dining and kitchen area could be improved. I'd suggest there is an alternative that avoids such an exaggerated doglegged end to the space that renders some precious unusable outdoor space and is a clunky resolution. You'd be better off building hard up to the end and enlarging the main outdoor areas so it's a single space, or potentially getting some external storage into it. The living/kitchen dining could be a lot cleaner and more spacious feeling. Would be good to understand where north is. On something like this you're better to exploit the site length rather than try and compromise the width. If north is up the page my instinct would be to flip the whole thing entirely having the kitchen running along the south. Also for a house this smallish scale arguably it would be more efficient to combine pantry and laundry for a more spacious outcome. Also I'd suggest that the outdoor kitchen is oversized and out of proportion for the site. It's always about balancing and prioritising elements, and in tight sites you have to work harder and make robust decisions about where you give & take. You can't afford to waste a square inch here, and if you want it to be awesome the design needs to be super efficient and to achieve a reasonable amenity that doesn't feel squeezed in the main spaces. It takes experience and skill to get this stuff right. Sorry if am seeming overly critical, but when engaged in resolving spaces for people I consider it a responsibility as a professional to ensure a client gets the absolute most out of the opportunity. There is so much underwhelming "vanilla" design work that people pay good money for, thinking that it's "good" when they are no idea how much better it can be. It doesn't have to necessarily be more expensive, but it does have to be throughly considered and properly managed, and opportunities identified and harnessed. Typically this involves considering a number of various broad options and then fine-tuning towards an outcome that is properly aligned to budget and project brief. Budget of course is the biggest factor to get a proper handle of, think here at least $500K+. If that's pushing it, then you'll have some hard decisions to make and need to be consolidating the extent of the expensive fit-out areas in conjunction with a more efficient design that achieves something in a smaller extension......if that's so then possibly one of the front rooms may have to be repurposed for bathroom.......again this comes back to starting the process by considering various options in broad form together with properly applied costings to each option so you can be making informed decisions on what's possible, rather than nitpicking detail on options that are likely beyond budget. Hope this provides some food for thought from a professional perspective Good luck with it PD :) www.pauldistefanodesign.com

Hello, I'm not a specialist, and I don't know if I can give you any good suggestions. However, every time I change houses, I work with a property buying company. They are the best ones in this domain, they aren't designers, but I am sure if you'll contact them they might give you some tips or someone to get in contact with to solve your problem. If I have to be honest, I won't make changes like this in my house, and I would choose to buy another one or change something inside my house. I'm not a fan of reconstructions. That's why I'm a little reserved about this topic.

unable to read any dimensions for the wiw and ens but my suggestions would be to steal space off the bedroom to make more useful space in the retreat and wiw and can't see need for such wide expensive sliding glass doors (what about fly screens?) and if you want curtain to be pushed back there needs to be some space for them to stack so why have such wide windows if part of the window will always be covered with some curtains but consider blinds or external roller shutters for all the small widows and a barn or sliding door door between bedroom an dretreat could slide behind furniture on the retreat or bedroom side