Combining Your Laundry and Bathroom: What You Need to Know

Combining a laundry and bathroom saves space and plumbing costs. Learn the WA waterproofing rules, layout options, and costs in Perth.

Why Combine a Laundry and Bathroom?

In many Perth homes, especially apartments in Subiaco and townhouses in Joondalup, floor space is at a premium and every room needs to earn its keep. Combining your laundry and bathroom into a single well-designed room can free up an entire room for other uses such as a study, nursery, walk-in wardrobe, or additional storage. It also consolidates plumbing into one location, which can reduce overall renovation costs by $1,500 to $3,000 compared to renovating two separate rooms independently.

Key Takeaways: Combined Laundry & Bathroom
Cost Savings	Consolidating plumbing can save $1,500–$3,000 compared to separate rooms.
Waterproofing	Must meet AS 3740 standards for both zones; full-floor membrane is recommended.
Ventilation	Requires high-performance ducted exhaust fans to manage high moisture levels.
Property Value	Stronger resale appeal in Perth through efficient, modern space utilisation.

Perth’s property values have made efficient use of space a genuine selling point at resale. A well-designed combined laundry-bathroom reads as a smart, modern solution rather than a compromise, provided it is planned correctly with proper zoning, ventilation, and waterproofing. Done poorly, it feels cramped and damp. Done well, it functions seamlessly for both purposes.

Key Planning Considerations

Waterproofing

A combined room must meet AS 3740 waterproofing requirements for both bathroom and laundry zones simultaneously. The shower area needs membrane coverage up to 1,800 mm on all surrounding walls, while the laundry zone needs floor waterproofing with 150 mm turn-ups at wall junctions. Because the entire floor is effectively a wet area, the simplest and most reliable approach is to waterproof the full floor area and all walls to the higher bathroom standard. The Building Commission WA will inspect and certify the membrane before any tiling can proceed.

Plumber repairing toilet in modern bathroom demonstrating wet area plumbing integration

Ventilation

A room that contains a shower, a washing machine, and a dryer produces a significant amount of moisture from three separate sources. Australian Standard AS 1668.2 requires mechanical ventilation in bathrooms without an openable window. For a combined room, we recommend a minimum 150 mm exhaust fan rated for continuous duty, ducted directly to the building exterior rather than into the roof cavity. A timer or humidity-sensor switch that runs the fan for 15 to 20 minutes after you leave the room helps control residual humidity and prevent mould growth on grout, silicone, and painted surfaces.

Plumbing Layout

Sharing plumbing lines between the laundry and bathroom saves on pipe runs and reduces installation time, but the layout needs to ensure adequate water pressure for simultaneous use. If someone is showering while the washing machine fills, both appliances need sufficient flow without a noticeable pressure drop. A licensed Perth plumber will assess your home’s water supply capacity, main pipe sizing, and internal pipe diameters to prevent this issue.

Layout Options for Combined Rooms

Layout	Room Size Needed	Laundry Visibility	Pros	Cons
Concealed behind cupboard doors	6+ sqm	Hidden when doors closed	Clean look, laundry completely out of sight	Requires wider room, doors need clearance
Stacked in alcove	5+ sqm	Partially visible	Compact, uses vertical space efficiently	Limited bench space above machines
Along one wall with partition	7+ sqm	Separated by half-wall or screen	Clear zone separation, good workflow	Needs larger room to work well
Under benchtop integration	5+ sqm	Visible but tidy	Uses vanity run, minimal extra space needed	Front-loader only, height restrictions apply

Materials That Work in Both Zones

Every surface in a combined laundry-bathroom must handle water, steam, cleaning chemicals, and daily wear. Porcelain floor tiles with a slip rating of P3 or higher are the standard choice for safety and durability. For walls, large-format tiles (300 mm x 600 mm or larger) reduce grout lines and make cleaning significantly easier. Cabinetry should use moisture-resistant MR MDF with a two-pack or polyurethane finish. Avoid standard melamine in any area exposed to steam, splashing, or dryer exhaust.

For benchtop and splashback material options that perform well in wet environments, see our guide to benchtop materials suitable for wet areas.

What a Combined Renovation Costs in Perth

A combined laundry-bathroom renovation in Perth typically costs between $15,000 and $28,000, depending on room size, the quality of fixtures and finishes, and the extent of plumbing work. While this total is more than a standalone laundry renovation alone, it is significantly less than renovating a bathroom and laundry as two entirely separate projects. The shared waterproofing, plumbing rough-in, tiling, and project management deliver genuine savings.

Planning both rooms together as a single laundry renovation and bathroom renovation also means one timeline, one project manager, one disruption period, and one round of dust and noise for your household to endure.

Is a Combined Room Right for Your Home?

If you have a separate laundry that is barely used and a bathroom that is due for updating, combining them is worth serious consideration. This approach works best in homes where the laundry is already adjacent to or near the bathroom, minimising the plumbing relocation required. Homes across Nedlands, Fremantle, and Balcatta with 1960s to 1980s floor plans often have laundries backing directly onto bathrooms with shared wet walls, making the plumbing integration straightforward and cost-effective.

James Officer

James Officer, has been renovating homes for more than 20 years. Over a decade ago, James founded Perth Property Improver with a clear vision — to create a reliable, professional service where homeowners could feel confident that their project was in safe hands. Over the years, he has built strong relationships with trusted local contractors, carefully weeding out the average from the excellent, so only the most skilled, dependable tradespeople work on your home.