My first reaction to your challenge was to block the toilet door in laundry. Make a new door opening on the other side and existing kitchen becomes a laundry. Therefore toilet has access to washing hands. Toilet is private, away from entryway to new extension. New laundry is accessible from new garage. Entry hallway is continuous to new extension. You could have the old laundry as a foyer type set up with a console or cupboards for storage. Or spend the extra and enlarge the existing bathroom into that the old laundry room. But this will just give you a narrow walkway. I feel a breather to the long hallway from the front door would be nice, before entering the new dining, kitchen, living area. The existing dining space could be used as a casual tv watching area, or add storage cupboards. Remembering with changes as you have shown, you will only have one internal living area, which will be in the new extension. Just think what extra space you require and use it for that purpose.

A google shot showing the roof and where the house sits on the block plus aspect would be helpful. Also family makeup, bedroomsa and does anyone work from home. Is the house Brick and tile on a slab etc.

Here is an aerial view. There is plenty of room at the back and an additional 1.8m on the right side between the carport/garage and boundary.

It is double brick on foundations with timber floors (Built 1964).

We have 2 kids who currently share a bedroom and the 3rd bedroom is used as a study. We would like the kids to have their own bedroom but they would also need a study area. I don't work from home but do currently use the study as a home office at times so sharing a single study probably wouldn't work. I guess they could have their own desks in their bedrooms.

My thought is to make kitchen into second bathroom. This could be part of a master suite with the dine and lounge. Existing master becomes lounge . Laundry and butlers pantry behind new kitchen. Bath goes to new bathroom allowing larger vanity in the existing bathroom in its place

where is north and please descibe your local climate and why do you need/want to demolish the existing carport and garage and have you checked with neighbours and council about extending a new garage to the boundary without a side path?

North is to the right. This is located in Adelaide. The rear of the house faces west so gets the sun in the afternoons.

The exisitng garage is small and is currently used for storage. We would like a garage where 2 cars can park and you can walk inside the home without having to walk in the front door. A single roller door at the rear of the new garage would allow for cars to drive through to a new carport as at some stage the 2 kids will have their own cars.

There is another side path on the left side of the house already so there is no need to also have one on the right side

have you checked about building the garage to the boundary to make it wide enough for two cars

what is the dimensions from side wall of house to fence where garage is to go

The right side of the house to the fence in 5.4m. A standard double garage roller door is 5m and I beleive the minimum allwed double garage width is 5.4m so I beleive it will just fit.

even if there is enough space for a small double garage have you checked with council and neigbours to find out if building on boundary is allowed as the decidon about the garage will impact available space for the extension and keep in mind that there will be floor space needed for wall thickness and for any steps up into the house direct from any side garage

The garage width of 5.4 is internal width for double. . So you will find it very tight if you have a large car to fit 2.

Opt 3

B1 and b2 are equal size and large enough for desks.

Are you on stumps? If so, don’t let current plumbing restrict the best layout. The cost will be a small component of the overall cost for what you’re considering doing. I think a link connection is probably the best option and maybe what OKL draws for you. That option touches the existing house the least which will be the least costly. The less you can alter the older house the less unforeseen issues you’ll uncover.

Thanks bigreader and everyone. The house is not on stumps. Its concrete foundations where all the walls are and then timber floors so I agree in theying to keep alterations to a minimum and just work with what is already there.

Another option. Running extension to the west to make most use of northern aspect

not sure what you mean abour the floors...can you crawl under the floor and are there a few steps at the front and back doors?? either way, my suggestions are based on your long term plans with older kids and include a similar "flat" roofed extension on a concrete slab with west facing alfreso, new kitchen with laundry and pantry, dining and family room with northern windows and direct access to the garage..subject to available space consider improving or replacing the current carport and including a verandah for coverd acess to the front door and use a shed in the backyard for storage so the garage can also be used as drive through rumpus room...renovations include the new bathroom and ensuite grouped near the existing plumbing with skylights and 4 generous bedrooms and/or rmulti purpose rooms...and, despite usually favouring a LINK, in this example i'm hoping floor and ceiling height will allow the "flat" roofed extensions all round, without changes to existing roof or external walls apart from closing unused windows and adding a new doorway between old laundry to the extension

Or this

Thank you all for your contributions and a special thank you to oklouise for your design. They have been very helpful and have given us a few options to think about.