Bit of a circle thing, the engineer will have trouble commenting on what you plan to do without drawings of the existing and proposed. Never met an engineer who could not work their magic on any structure, but there will be simple and cheaper methods and then there can be some super expensive ones. Builders and engineers should be communicating as well. If i were you, i would have identified a builder, get a good architect to work with you, your budget, the builder and engineer, and town planner if this requires DA approval. Overshadowing is the shadow your structure casts on the neighbors property. Overlooking is when they can see into your property, some councils have means to prevent this and the last to build normally has to screen their windows to prevent overlooking, some require only high windows, not all councils and not all property sizes will be affected. If the architect draws in a 3D package it is a simple matter to show you where the shadows land at any time and day of the year, based on you address. If allowed to build that top story, they can show you if you shade your pool. This is a big investment from you, most likely you would be living with the results for years, i would imagine that you would want the best outcome for your family, and to engage professionals would be the way to achieve those outcomes. Thoughts and ideas from forums like this are great, but sometimes they are not aware of the outcomes of comments which might affect your whole project, and councils around the country all have different requirements. Check and check again. What is allowed in Brisbane with height and upper floor window sizes on smaller blocks, will not be allowed in Melbourne, or Sydney councils. Shadowing while really not an issue in Brisbane, will be a huge issue in Melbourne, so get a local team. Ros

oops with the diagrams.. Note that the "shed like" part of the extension joins onto what must have been the original lean to that extends all along the original villa part. Note the pillar in the living area, that is structural. Another strange aspect is that the toilet juts out into the open plan space ( I think that could be remedied with $$s and it could fit into the main part of the family bathroom by taking out the old corner spa and putting in a smaller freestanding bath for example) . By the way, the "retreat" is actually a courtyard that could be a nice feature if properly landscaped etc. A new roof (to get a new roof line) might work on the shed like part, but the walls around the west and southern perimeters of the space are just windows/doors so I don't think they could support the weight of a "proper" roof rather than glass? Can you see that plan well enough and what info do you still need OkLouise (and others)? Thanks again for any ideas :)

Sorry but I am confused by the purpose and function of this entire space. Form follows function.... But I am not seeing the function being clear so that is causing the problem with the design. Your layout and comments imply that: someone is playing piano, someone is watching movie in theatre room, someone is playing with toys, someone is watching huge TV in living area, someone is cooking.... All at the same time. If so, then these needs will dictate the design... Or whatever your specific needs are. I would start by defining function priorities (storage, view, access, etc) and then work from there ~ prioritise these functions and estimate boundaries/size to define zones that are needed. Have another plan of things that cannot be changed easily - windows, kitchen, powerpoints - with dimensions from reference point. Ask questions like: how often will we/I use this _ do we really need separate piano room_ do we need to use French doors daily _ do I want to walk past new lounge suite carrying food _why would iI use both theatre room and living room at same time _ do I need all these windows or can I fill in one to get more function in the space _ Good luck as you will have to balance needs and wants!

the carport could be converted to a separate rumpus or MPR with a concrete slab at ground level with access through the original entry porch enclosed to allow all weather access and use the old driveway for an outdoor sitting area and/or maybe use my new corner study as an alternate location for a new laundry to allow more space in the kitchen but it will need careful planning of a new "front" gate and footpaths to show clear directions to make sure visitors know how to find the "front" door.. attempting to access the new rumpus from the family room would create challenges with doorways, changing old external walls, ceiling and floor heights so i would simple enclose the carport space and keep it separate from the main house and you should be able to find inspiration from many examples of similar era homes (eg Pettit and Sevitt) that had timber cladding combined with blond brick walls BUT it would be very useful to organise a site plan showing the house and accurate distances to all boundaries, scale sized buildings, existing driveways, front gate, location of street address, power, waters, sewerage, precise direction of north and any trees that you would keep...an accurate site plan and more photos could help inspire other options or confirm that my suggestions are either possible or not