A Melbourne homeowner is planning a two-bedroom granny flat for an adult child now, with the option to rent it later. The first sketch has one generous bathroom and useful hallway storage. The second squeezes in two ensuites, but the living room becomes tighter and the laundry loses its bench.
Both plans have two bedrooms. They will not feel the same to live in, build or maintain.
For a compact Victorian granny flat, the bathroom count should follow the likely occupants, the available floor area and the complete project budget. Two bathrooms are not automatically better, and one bathroom does not automatically make the design too basic.
Start with the 60 m² limit
In Victoria, a small second dwelling has a gross floor area of 60 m² or less. The official measurement includes all roofed areas and is taken from the outside of external walls or the centre of party walls.
That means every additional wet area competes with bedrooms, wardrobes, circulation, laundry space and the main living zone.
The right comparison is not simply one bathroom versus two. It is what the complete two-bedroom granny flat design gains and gives up in each version.
When one bathroom is usually the stronger layout
One well-positioned bathroom often works best when the dwelling is intended for a couple, a parent with a guest room, or one person using the second bedroom as a study.
It can leave more room for:
- a wider shower and easier movement
- a separate toilet
- linen and cleaning storage
- a practical laundry zone
- larger wardrobes
- better circulation between bedrooms and living areas
A single bathroom can also concentrate plumbing into a simpler wet zone. This does not guarantee a lower final price, but it may reduce duplicated fixtures, waterproofed areas, cabinetry and plumbing work compared with two complete bathrooms.
The main weakness is morning congestion when two unrelated adults share the home. A separate toilet can relieve that pressure without using as much space as a second shower and vanity.
When two bathrooms may make sense
Two bathrooms become more useful when both bedrooms are expected to operate as genuine adult rooms.
Examples include:
- two adult siblings sharing
- a parent and live-in carer
- two unrelated tenants
- regular long-stay guests
- a future rental aimed at occupants who value private facilities
In these cases, two ensuites can improve privacy and reduce the need for visitors to cross the living area at night.
But the second bathroom should solve a real use problem. If it only exists because a larger house usually has two bathrooms, it may consume valuable space without improving the way this smaller home works.
The hidden floor-plan trade-offs
Adding a second bathroom rarely affects only one room.
Bedroom size and storage
An ensuite needs a doorway, wall length and circulation space. The bedroom may lose a wardrobe, bedside clearance or flexibility in bed position.
Living and dining space
On a compact plan, a small change near the bedroom wing can shorten the kitchen wall or reduce the distance around a dining table. These losses are easy to miss on an empty drawing.
Laundry planning
The laundry still needs a workable location. Hiding a washer in a bathroom can be efficient, but the arrangement must leave practical access and ventilation. Two ensuites plus a separate laundry can put pressure on the shared living area.
Windows and privacy
Bathrooms need privacy, light and ventilation planning. Their position can affect where bedroom and living-room windows are placed, especially on a narrow backyard site.
Review the room arrangement as part of the wider granny flat design, not as a plumbing decision made after the plan is fixed.
Compare the complete cost, not just the fixture list
A second bathroom can add more than another toilet and shower.
The scope may include extra waterproofing, tiling, ventilation, plumbing runs, drainage points, electrical work, cabinetry, mirrors, screens, fittings and labour. The impact varies with the plan, specification, construction method and service layout.
Keeping both bathrooms close to the kitchen or laundry may be more efficient than placing wet areas at opposite ends of the building. Even then, the quote should identify what is included rather than treating the upgrade as a simple allowance.
Our Granny Flat Cost Victoria guide explains why the building design, site work and service scope need to be compared together.
Think about the intended occupants
The strongest layout starts with a realistic use case.
If one bedroom will mainly be a study or occasional guest room, a second full bathroom may deliver little everyday value. If two adults will share for several years, privacy may matter more than a slightly larger lounge.
For rental use, avoid assuming that another bathroom will automatically create enough extra rent to repay its cost. Check local comparable properties and likely tenant groups. The Rental Income Guide can help you separate rental appeal from an unsupported return assumption.
It is also worth asking whether the design can adapt. A shared bathroom with a separate toilet may suit one occupant today and two occupants later without committing a large part of the floor area to two complete ensuites.
Check whether the plan fits the block
The internal layout cannot be assessed in isolation.
A wider bathroom zone may change the building footprint, window positions or the side of the dwelling used for services. On a constrained Melbourne block, that can affect setbacks, private outdoor space, access and the route for drainage connections.
Before paying to customise the plan, compare both bathroom options against the actual property through a Land Eligibility Check.
A practical decision test
Use these five questions before choosing:
- Who is likely to use each bedroom most of the time?
- Will two people regularly need the shower, toilet and vanity at the same time?
- What floor area, storage or living comfort is lost in the two-bathroom version?
- What extra work is included in the complete project quote?
- Does the revised footprint still suit the block, services and access?
If the second bathroom answers a recurring privacy or household need, it may be worth protecting in the plan. If it mainly adds a feature to the listing, one better bathroom and a separate toilet may be the more balanced design.
The practical takeaway
For many compact two-bedroom granny flats, one well-designed bathroom provides the best balance of space, cost and maintenance. Two bathrooms can be worthwhile for two adult occupants, shared rental use or long-term privacy, provided the plan does not compromise the rest of the home.
Choose the occupants first, then test both plans on the real block.
If you want to know which layout is realistic for your property, start with a Free Land Check. MPLUS can review the address, obvious site constraints and design direction before you commit to bathroom upgrades or a fixed floor plan.
