I’d start by moving the bathroom to bed 3. Is the laundry suitable for study? You could rebuild it up at kitchen level. If kitchen is ok I’d keep it to save cost but add an island .. the carport notch could be potential study or the garage

Then the easiest extension is the master as the roof is pitched in that direction. May need some excavation in Back yard and a small retaining wall and drainage. This is where costs add up, hence kitchen has to stay. But if you did this can add in 2nd bath and laundry.
With the bathroom gone you can add cupboards along hall wall for more storage, and open up to deck. If you do this all budget is upstairs.
Get builders in to quote, I note that it is a really bad time to do reno with timber and plaster in short supply and plasterers all go to flood zones. So plan, maybe tackle new bathroom and then hold.

Thanks Kate. Yes we definitely think an extension for an ensuite and WIR from Bed 4 is the best idea, but hadn’t considered moving the laundry there too. I might have a look at possible layouts for that idea.

I think the cupboards along the hall would be a fantastic idea and had even had that idea if we were leaving the main bathroom in place, it would just be a narrower bathroom but still functional due to its length (and with the toilet combined not separate).

Moving the bathroom to Bed 3 means reducing to 3 bedrooms (if we don’t enclose downstairs) which we were hoping to avoid. But definitely food for thought. The roofline off the kitchen is rather prohibitive for extending on that side, but also hadn’t thought to convert laundry to office. I had thought about removing it altogether and opening up kitchen that way though.

Another idea is to knock a door in the back of the downstairs foyer, and putting the laundry in there. You have internal access with the added bonus of being able to hang washing there in wet weather.

Or knocking into the useless carport nook for laundry. But it is out of way to get to clothes line I expect.

have you checked with council to find out if it's legal to convert the front deck to a new room and add another carport, what is the minimum distance allowed from the front boundary to any new two story additions, what is the width of the block and the distance from the existing house to the front and side boundaries and what is the minimum head height downstairs?

oklouise - the deck was an addition by previous owners and they had to seek council approval for the variation of a 4.5m setback from the road alignment in lieu of the required 6m.

An addition of a carpet will require council approval - there are a number of houses on our street who have constructed a carport right on the boundary (there are also limitations related to sewer on the left hand side that we have to work through).

Regarding the conversion of a portion of the deck into a room - I will have to seek verification on that with the council, and it’s only an idea recently so haven’t thought through the implications as yet.

I have attached the site plan from this below.

The minimum head height directly below the house in the garage is 1.95m.

any extension involves major challenges for the roof so my suggestion would be to demolish the existing laundry and add two separate extensions to include a pantry and laundry in place of the old laundry (at the same floor height as the kitchen) and a wiw and ens attached to existing bed 4, extend the rear deck to connect with the higher level of the backyard and improve small bedrooms by stealing space to create biw for beds 2 and 3, rearrange the family bathroom and enclose the downstairs "notch" to create a small home office accessed from the entry foyer but perhaps you will need to decide which areas are most urgent as it would be surprising to achieve all this within budget but sections could be done in stages as funds allow..

I appreciate you taking the time along with your response oklouise! This has given us much to think about. There are some great ideas in the layout you have provided and as you say, now we will need to spend some time prioritising the additions/modifications.

By extending the deck across the kitchen will allow for a wide sliding/stacking/ bifold door plus an outdoor kitchen continuing from the kitchen bench. A long 900 Island with a dropped table section for the little ones to sit at.

A 3 way bathroom, bath with WC, shower with vanity and powder room should work for a young family. Making bedrooms 1 & 2 the same size. Bed 3 a multi function space.

You could look at using the unparkable garage as the office with a door coming of the entrance foyer towards the rear and add a window across the front. If the ceiling height allows the laundry running back from the foyer towards the side door via a door. You could look to add a laundry chute from the first floor from within one of the bedrooms. possibly a lift up top on a cabinet, it doesn't have to end up in the laundry.