Correction dimensions of the existing back room are 4.47m X 6.60m

When you say budget is limited, how limited? Have a look at approved permits for your area on the Council website, it will give you a rough idea of what you’re up for. Have you had a builder in to evaluate if your lower story could support an upper story?

my suggestion expands the downstairs to the boundary and includes generous eat in kitchen with study nook, pantry and skylights...shower room under stairs, separate vanity room for extra privacy, separate toilet and laundry...upstairs has setback of at least 150cm with L shaped enclosed stairs, master bed with ens and biw or optional wiw overhanging downstairs alfresco but i would expect to demolish existing area to build new two story extension to achieve best results

Great idea OKL. Two story extension minimising alterations to the existing building is a great idea and use of space.

Thank you. As the plan was to demolish the rear 'room' (the original kitchen and lean-to) entirely the new ground floor build should be suitable for an upper storey. Budget is only $500 - $600k. Will have a look on the Council website as suggested.

I like the suggested location of the bathroom etc in the floorplan but was wanting the back wall to be entirely sliding windows to open the room to the outdoors.

budget should be possible and should be able to fit sink and dw on the the north wall to have sliding glass doors to the backyard but that makes lots of empty floor space in the dining area but not enough for an island plus dining table unless more space stolen from backyard?...what are the walls, floor and roof (of the front three rooms) built out of and please include distance from existing house to rear boundary, do you have backyard street access and/or backyard buildings and a Google Earth images of the roof and some photos would also help

If you lose the bench on rear wall then add island that continues into dining space