Cost to Add a Bathroom in Australia (WA): Pricing, Process, and Smart Design Tips

Thinking about adding an ensuite, family bathroom or powder room? A well-planned bathroom addition to your house can lift liveability and resale value, especially when paired with a kitchen or laundry upgrade. Here’s a practical guide to the cost to add a bathroom in Perth and across WA—plus layouts, finishes, approvals and timelines—so you can budget with confidence and avoid costly surprises.

Why add a bathroom?

• Improved functionality: An extra ensuite or powder room eases morning congestion and suits multi-generational living.
• Value uplift: Buyers prioritise additional bathrooms in family homes and premium apartments across Perth and regional WA.
• Renovation synergy: If you’re planning kitchen renovations Perth, consider bundling a bathroom or laundry renovation to minimise disruption and trade mobilisation costs.

At Joyce Kitchens we design and build cohesive spaces—kitchens, bathrooms, laundries and wardrobes—so materials, colours and hardware flow through your home, from a shaker kitchen to a contemporary ensuite.

What does a “bathroom addition” include?

Typical inclusions: design and approvals, plumbing and electrical rough-in, waterproofing, tiling, shower/bath, toilet (WC), vanity, mirror/shaving cabinet, lighting and ventilation, glazing, and painting.

Bathroom addition process in WA

1) Design consultation and measure

We start with a site measure to confirm access, structure, and service locations. Our designers create a layout that suits your home—ensuring adequate storage, a functional vanity, and practical circulation around the shower and WC.

2) Documentation and approvals

• Building permit may be required for structural changes or wet area additions (consult your local council).
• Plumbing and drainage must comply with AS/NZS 3500 (by a licensed plumber). Waterproofing must comply with AS 3740.
• Electrical work must be done by a licensed electrician (AS/NZS 3000). Mechanical ventilation to NCC requirements.

See guidance from WA Building and Energy, HIA, and Master Builders WA.

Considering sweat equity to trim the budget? This diy bathroom renovation guide outlines tasks to DIY vs. outsource.

3) Build sequence

1. Demolition and structural framing (if extending)
2. Services rough-in (plumbing/electrical), ventilation ducting
3. Sheathing, screeding, falls to waste, and membrane waterproofing
4. Tiling (floors then walls), glazing, and painting
5. Cabinetry and benchtops, fixtures and fittings (fit-off)
6. Testing, clean, handover and warranties

Materials and finishes that work in Perth homes

Bathrooms are tough environments—steam, cleaning chemicals and daily wear. Choose moisture-resistant cabinetry and surfaces with strong warranties.

• Vanities and cabinetry: moisture-resistant board, custom cabinetry WA with soft-close drawers, durable 2-pack or laminate doors, finger-pull or handleless cabinetry.
• Benchtops: porcelain/sintered stone, solid surface, compact laminate, laminate; coordinate with engineered stone benchtop alternatives used in the kitchen.
• Tiles: porcelain floor tiles with slip resistance; ceramic or porcelain wall tiles; feature mosaics or splashback tiles for niches.
• Fixtures: undermount or semi-recessed basins, WELS-rated tapware, frameless or semi-frameless shower screens, LED task lighting.

Benchtop comparison for bathroom vanities

Coordinating styles across rooms? Many clients pair a coastal shaker kitchen with a classic white-and-oak ensuite, or a modern galley kitchen with a minimal concrete-look bathroom. We can match vanities to your walk-in pantry, scullery or butler’s pantry finishes for a seamless home.

Layouts and styles

Popular bathroom additions

• Compact ensuite: 1.6–2.2 m wide fits shower, WC and 600–900 mm vanity.
• Family bathroom: add a bath, double vanity, and storage tower.
• Powder room (toilet + basin): ideal near open-plan living for guests.

Design touches that elevate the space

• Shower niche and frameless shower screen for a clean look.
• Wall-hung vanity to increase floor visibility in small rooms.
• Matte black or brushed nickel tapware, and heated towel rails.
• Task and ambient lighting—mirror backlights, dimmable LEDs.

Costs: How much to add a bathroom?

Here are planning ranges for the cost to add a bathroom in Perth/WA in 2025. Every site is different—consider these a guide, then talk to our team for a fixed design and itemised quote.

Typical ranges (conversion of existing internal space)

• Compact powder room addition: $10,000–$25,000
• Small ensuite addition (shower, WC, vanity): $28,000–$55,000
• Family bathroom addition: $35,000–$65,000

Typical ranges (new extension or major reconfiguration)

• Bathroom addition with structural works/extension: $45,000–$90,000+
• Second-storey bathroom addition as part of level addition: highly variable; allow $60,000–$120,000+ within overall build

Where the money goes

• Plumbing and drainage: $3,000–$12,000+ (more if relocating stacks or cutting slabs)
• Electrical and ventilation: $1,500–$4,000
• Waterproofing and screeds: $1,200–$3,500
• Tiling and stone/porcelain: $5,000–$15,000+ (tile size and patterns affect labour)
• Cabinetry and benchtops: $2,500–$8,500+
• Fixtures (WC, basin, taps, shower, bath): $3,000–$10,000+
• Glazing/shower screens and mirrors: $1,000–$3,500
• Design, documentation and permits: $1,000–$5,000
• Builder supervision, site costs and contingency: allow 15–25% margin + 10–15% contingency

Timeframes: after design and approvals, most bathroom additions run 3–8 weeks on site. Allow 2–6 weeks for design selections, lead times and permits before construction.

Ways to keep costs under control

• Place the new bathroom near existing plumbing to reduce rough-in costs.
• Choose quality mid-range fixtures; invest in waterproofing and ventilation (non-negotiables).
• Standard tile formats (e.g., 300×600 mm) are faster to lay than intricate mosaics.
• Bundle your bathroom renovation Perth with kitchen or laundry updates to share trades and deliveries.

If you’re creating a private retreat, see ensuite bathroom renovations for styles, compliance and WA-specific timelines.

Perth case-style examples

Fremantle character cottage: ensuite conversion

We reconfigured a main bedroom robe to create a 1.8 m-wide ensuite with wall-hung vanity, subway wall tiles and terrazzo-look floor. Kept plumbing on one wall and installed quiet in-line ventilation for heritage windows. Cost band: low–mid $30k. Duration: 4 weeks on site.

Baldivis family home: powder room addition

Client needed a guest WC near the open-plan kitchen. We carved a powder room off the hallway, using compact laminate for the vanity and a space-saving in-wall cistern. Cost band: $15k–$20k. Duration: 2.5 weeks on site.

Practical pre-build checklist

• Confirm space: width, door swing, and circulation clearances.
• Choose layout: shower-left or shower-right; niche position; towel rail locations.
• Plumbing: check access for new wastes; avoid excessive slab cutting.
• Ventilation: mechanical extraction to outside (avoid recirculating only).
• Waterproofing: full shower enclosure and around bath per AS 3740.
• Electrical: GPOs, heated towel rail, mirror demister, RCD compliance.
• Finishes: tiles, grout colour, vanity finish, benchtop, mirror cabinet.
• Fixtures: WELS-rated WC, basin, mixers, shower set, bath (if any).
• Lead times: order tiles, screens and cabinetry early to lock dates.
• Approvals: confirm permits with council; builder and licensed trades engaged.
• Budget: include 10–15% contingency; understand PC/PS allowances.
• Handover: warranties, care guides, and maintenance schedule.

Ready to plan your bathroom addition?

From space planning to custom cabinetry WA, our Perth team coordinates design, approvals, and trades alongside your kitchen, laundry or wardrobe project. Book a free in-showroom consult to discuss the cost to add a bathroom addition tailored to your home.

FAQ

How much does it cost to add a bathroom in Australia?

As a planning guide, converting internal space into a new bathroom in Perth/WA typically ranges from $28,000–$55,000 for an ensuite and $35,000–$65,000 for a family bathroom. A compact powder room can be $10,000–$25,000. If you’re extending the building or adding significant structure, allow $45,000–$90,000+. Every site is different—talk to us for a fixed design and itemised quote.

Is it cheaper to add a bathroom or renovate an existing one?

Renovating an existing bathroom is generally cheaper. Adding a new bathroom involves extra plumbing and drainage, potential structural work, and approvals. If you can repurpose adjacent space and keep plumbing on one wall, you’ll narrow the price gap.

Do I need council approval to add a bathroom in WA?

Often yes. Structural changes and new wet areas usually require a building permit. Plumbing must be done by a licensed plumber to AS/NZS 3500, waterproofing to AS 3740, and electrical to AS/NZS 3000. Check with your local council or the WA Building and Energy website for permit requirements before work starts.

How long does a bathroom addition take?

Allow 3–8 weeks on site after approvals for a typical bathroom addition, plus 2–6 weeks for design selections, documentation, lead times and permits.

What’s the most cost-effective way to add a second toilet?

Convert existing space near plumbing—often a section of laundry, under-stairs or a robe—to a powder room (toilet + small basin). Expect $10,000–$25,000 in Perth, depending on access, finishes and whether slab cutting or ventilation upgrades are needed.