New toilet with access from new laundry. Window in toilet on north side. Ease of plumbing access under deck.

If you’re doing that level work particularly involving external walls and all the permits, I’d consider adding an ensuite. That will give a substantial property value uplift and give yiu the second toilet.

Thank you both for your feedback and suggestions.

as you say, adding an ensuite is likely more valuable, just means i probably wont get the family size laundry as our existing laundry is a euro and our current bathroom needs to absorb some of the study space to for a separate shower and bath. things to think about.

What do you want in your bathroom? Shower, bath, one or two vanities, a toilet? Is there an existing toilet somewhere in the house?

Why does your current bathroom need to absorb study space? It is 3300x1820mm. This is enough room for a bath,shower, toilet and vanity. If you have another toilet somewhere else, and create a new toilet. You can delete the toilet from bathroom and have even more space. I think you have underestimated the size of your existing bathroom. That is why, in my first post I have not made any changes to bathroom area.

Is Something like this what you are thinking ?. I haven’t drawn to scale just riufmgh idea

But would be cheaper to simple turn study in laundry/2nd bath

We dont have another toilet in our house currently which is something as a family of four we would like to add in.

in our bathroom i would like a bath, separate shower, toilet and a vanity- single would be ok.

i will try mocking diagram dreamer in my current bathroom and see how the space feels.

thank you kate for your diagrams too- helpful ideas.

Alternative no extension

Just following with a photo of my earlier rough sketch. Always an inset bath, not a freestanding bath. Unless you want to spend hours cleaning in spaces that can’t be reached. And you said you wanted are “large laundry”. So using the study, maybe changing the window out for a smaller opening window for ventilation would allow large storage areas and room for all appliances, trough, hanging space etc.

Emma M, Here is a rough sketch of how the study could be your new laundry.

Or this set up for your bathroom. (Your entrance door can stay where it is.). This bathroom is 3350mm long.

What additional functionality are you seeking to add by having a large laundry? Is that the only way to achieve what you’re after?

ideally i would like a room to store our linen, the vacuum, mop etc which currently dont fit in our euro laundry. In addition to housing the school bags etc as we dont have a designated ”dump zone” at our entry points - no room.

i had initially considered making the current bathroom the laundry and adding a door to the deck so it could become a mudroom / laundry.

Does the family enter the house at the rear or via the front? Be realistic, if they come in the front door no kid is going to head to the back of the house to hang up a bag. I love a good drop zone but it actually has to fit with the way your family lives. Not moving walls and keeping in the same footprint will be the most economical.

We use both the front and back door- probably the back more often as it is closer to the car.

3 options with extension

Is your home on a concrete slab, or does it have timber floors with underfloor access?

Timber floors with underfloor access.

thanks again everyone for your input ans suggestions.

Good luck. The ensuite option is very tight so beware.