with the wide garden next to the kitchen, laundry and living area it seems that this is the extra space you need to use for a new master suite and keep all three small bedrooms the same..there's no advantage to attempting to enlarge the three small bedrooms and much more cost effective to build a new master suite or granny flat and use the old master suite for your son or a guest room and give him two bedrooms to use and there's still the central bedroom for a study (5 bedrooms including two with ens and a family bathroom!)... with the angled front and side boundaries the real opportunities can only be determined by a careful site inspection and i'd engage a local architect or designer to help decide the best new floorplan including the guest house and pool...based on assumed setbacks and approximate dimensions my suggestions include a new master suite, laundry/mudroom and some alterations to the layout of the living areas for a more generous kitchen/dining area open to the family room (with study nook for your son and more comfortable access to the bedrooms with a raised floor instead of walking up and down three sets of stairs) and keep the living area as a separate adult living area

What size is your block, and what size is the current home. In Perth there is the 50% open space ratio, so that will help in working out how much extra building is allowed.
You never mentioned on your other post, that you already had a carport. This could be enclosed to make a garage, then extension built to the right of block. With new master suite, and mudroom in area near the existing laundry.
Assuming your home is double brick, it will need some thought as to which walls are worth moving.
I would rather have three decent sized bedrooms, used all the time, than four small ones, with one vacant. You should consider how you live now and in the future to whether your family requires 4 bedrooms.

Also, the granny flat will have to form part of your building ratio.

do you have an original floorplan and can you please answer, how many fireplaces, I can see one chimney and is the living room sunken (siriuskey)

Hi OkLouise LHS is 1.5m from boundary and approx 1.2m RHS. We will be dividing the land to the right of the kitchen to build a seperate unattached granny flat. 70sqm 2bed 1bath for my elderly parents and at some point extra income as rental.

Your plan shows a pool and home office. But the overhead photo does not. Has the pool and office been built? Or is this part of the wish list?

That's awesome OKLouise. The land to the right of the garage is definitely granny flat. How would you adapt this plan if we could only come 2.5m forward from the front bedroom closest to entry? I really appreciate your input. Very knowledgeable on these matters.

my knowledge has come from personal experience including building a granny flat and numerous extensions including rebuilding roofs and external walls and the problem with a "granny flat" is that it has a whole lot of extra conditions more costly than a same sized extension and, the problem with attempting to come forward 2.5m, is what would you do with that space? the extra 2.5m is not big enough for anything useful and can't be added to the front bedrooms without removing the front wall and changing the roof and spoiling what's already there, ..it's not cost effective to change the external walls and roof ..there's already a carport in the front garden, you've already decided to use the side garden for a granny flat and the rear garden for a swimming pool so there's no other options for useful expansion so you need to focus on improving what you already have inside ..the cost of a separate granny flat would never be recouped in rental income and the space doesn't look big enough for a separate two bedroom self contained granny flat ...you could still use an extension for your parents but without accurate dimensions we can't be sure of what's really possible?...do you already have Council approved plans for the granny flat?..there's not enough space for a separate entry so i don't understand how it could be approved....your wish list would probably cost more than the house cost to buy so you need to invest in help from a local professional who can work out exactly what space is available and help you decide what's most important and cost effective ..

To enclose garage it needs to have internal dimensions of 5.5 m width x 6 m length. Without that width you can’t fully open Car doors and they will get scratched Can that be achieved?

I would think a lockable garage single or double is necessary to keep hubbies work vehicle and all the required tools safe, what is the distance to the L/H boundary? (siriiuskey)

your house looks like an 80's home with a sunken lounge. I live in an 80's single level house like yours and love the spacious feeling, do you have raked ceilings?

If it was me I would make small changes so suggest the following,

1) If the eave is deep enough I would push your sons bedroom wall out this would give him a good sized bedroom with access to the next bedroom and bathroom for his "PAD"

2) There is a flow problem with the house with accessing the bedrooms as you have to step down into and back up from the family/rumpus/living at two points. Keeping the "fireplace" insitu I would take part of the internal bedroom to allow for a passage across from the entrance to the bedroom wing. the reduced bedroom would make a great study or guest room. you can keep both step down points or close off the wall from the fireplace to the master bedroom

3) another problem with the house is internal access to the alfresco, at the moment it would only be via the family/rumpus or master bedroom, I suggest that the alfresco decking be split level to allow for large sliding doors coming off the new open plan kitchen. The door into the existing kitchen be kept but remove the laundry which will allow for a bigger dining table.

4) The laundry could be moved into the planned office/guest.pool room which would be perfect if there was access down the L/H side of the house for hubbie coming home and needing a cleanup which would be done in the same space, which could also be his man cave!!

5) The granny flat needs to be sorted by a local designer to get the best possible result, I have heard that a studio is more readily approved over a granny flat (siriuskey)

Siriusky, I think the fire places your seeing, might be corner indoor planters. Which were all the rage in the late 1980's. And yes I think this home is in a suburb, where a lot of the homes have wonderful ceiling heights. Usually good size living areas, but small bedrooms.

Beau Mitchell, is there still a large floor to ceiling window in the front living room? If so, can this be made into a walkway to the new extension/granny flat.

In this crude plan I have moved master into living using extending plumbing towards from laundry into en-suite which can have direct access from garage. The other option is to move laundry to front of house somewhere.
I would do 3 bedroom with a den that could be a fourth bedroom. I have put den at back but it could be swapped with b3.