Planning a Bathroom Renovation in Canberra?

Bathroom plumbing in Canberra runs in three stages: rough-in, where the pipes get moved; waterproofing, which ACT building regulations require; and fit-off, where the fixtures go on. The plumbing part of a bathroom renovation usually lands between $3,000 and $8,000 depending on how much you are changing, going by figures from Hipages and ServiceSeeking.

What Are the Three Stages of Bathroom Plumbing?

The sequence is the same on every bathroom, and knowing it makes it much easier to book your other trades in the right order.

Stage 1: Rough-In

The rough-in is all the pipe work, and it happens after demolition and before tiling. The plumber moves the water supply lines and the waste pipes to suit the new layout. Keep everything where it is and the rough-in is a small job. Move the toilet, relocate the shower, or go from a single to a double vanity, and it gets bigger and dearer.

The work covers new hot and cold supply points, repositioned waste outlets, and the connection back into the existing drainage. Plenty of Canberra homes are slab on ground, and if a waste has to move on a slab, someone is cutting concrete. That adds a day and it adds cost.

Stage 2: Waterproofing

Waterproofing is not optional. The Building Code of Australia and ACT building regulations require every wet area to be waterproofed to AS 3740. That covers the whole shower floor, the shower walls up to a minimum height, and anywhere else water can pool or splash.

The plumber puts in the shower waste and the floor waste, then the waterproofer lays the membrane over it. The membrane has to be inspected and passed before anyone tiles. Get this stage wrong and you get leaking showers and water in the structure underneath, and by then the repair means pulling the tiles up again.

Stage 3: Fit-Off

Fit-off comes after the tiling and painting are done. This is the visible gear: taps, toilet, vanity, shower head, towel rails and accessories. It is the last plumbing stage and takes anywhere from half a day to a full day depending on how many fixtures you have.

When Should You Book the Plumber in Your Renovation Timeline?

The plumber is one of the first trades you want involved, before anyone swings a hammer. There are four points where you need them:

1. Before you sign off on the design. Run the layout past your plumber. Shifting a toilet from one wall to another looks like nothing on a plan, and depending on where the existing waste runs it can be expensive or simply not worth doing. Five minutes on the phone at this stage has saved plenty of people thousands.
2. Demolition day. Water and waste lines have to be capped off before the demolition starts, otherwise you get a flood, sewer gas, or both.
3. Rough-in. Straight after demolition, the plumber is back on site putting the new pipework in before the waterproofer and tiler can start.
4. Fit-off. Booked once the wet trades are finished: waterproofing, tiling, painting.

The most common mistake we see is booking the plumber too late. Good plumbers in Canberra are booked out, and a renovation sitting idle for a fortnight waiting on one is expensive in ways that never show up on a quote.

What Are the Most Common Plumbing Changes in a Bathroom Renovation?

These are the changes we get asked for most, and what each one actually involves:

• Moving a toilet. The dearest change on the list, because the waste pipe is the big one at 100mm and it has to keep the right fall the whole way. Shift it more than a metre and you are usually cutting the slab. Around $800 to $2,500.
• Relocating the shower. New hot and cold supply lines plus a new floor waste. Simpler than a toilet, though it still means slab work if the waste moves. Around $600 to $1,500.
• Going from a single to a double vanity. Extra supply points and a wider waste connection. Around $400 to $800 for the plumbing side.
• Putting in a freestanding bath. The waste and supply connections sit at floor level and often do not line up with what a built-in bath used. Around $500 to $1,200.
• Upgrading to a rain shower head. Usually means moving the supply pipe from the wall up into the ceiling. Around $200 to $500.

What Do ACT Waterproofing Regulations Require?

Bathroom waterproofing in the ACT has to comply with Australian Standard AS 3740. In practice that means:

• The whole shower floor is waterproofed, corner to corner
• Shower walls are waterproofed to at least 1,800mm above the finished floor level
• The area around the bath is waterproofed to 150mm above the rim
• Wet area floors outside the shower are waterproofed and fall properly to the floor wastes
• Every penetration through the membrane is sealed with a proper flange

A building certifier inspects and signs off the waterproofing before the tiler starts. Skipping the inspection, or doing the membrane badly, is behind most of the failed bathrooms I get called to look at.

How Much Does Bathroom Renovation Plumbing Cost?

What you pay depends almost entirely on how much you move. As a rough guide:

• Like for like, same layout with new fixtures: $2,000 to $4,000
• Minor layout changes, moving one or two items or adding a fixture: $3,500 to $6,000
• Major layout change with new positions and slab work: $5,000 to $8,000 and up

Those figures cover the rough-in, working in with the waterproofer, and the fit-off. Fixtures like taps, the toilet and the shower are either supplied by you or quoted on top.

Should You Use Your Builder's Plumber or Hire Your Own?

If a builder is running the whole renovation, they will have a plumber they use. That is the easy option, because the builder handles the scheduling and wears it when the timing slips. You are not obliged to take them, though.

Booking your own plumber gives you a say in who does the work and what you pay for it. You can get a few quotes and pick someone you actually want in your house. In return you inherit the scheduling headache.

If you are running the job yourself as owner-builder, you are booking the plumber directly, so get the order right with your tiler and waterproofer. The rough-in has to be finished before the membrane goes down, and the membrane has to be down, inspected and passed before the first tile goes on. Get those out of order and something gets ripped up.

What Permits and Compliance Are Needed in the ACT?

Any bathroom renovation in the ACT that involves plumbing work has to comply with the Building Act. That means:

• Your licensed plumber lodges the plumbing work notices with Access Canberra for any regulated work
• Structural changes, or a significant change to the layout, may need building approval from a certified building assessor
• The waterproofing inspection has to be completed and signed off before tiling
• Your plumber gives you a compliance certificate once the plumbing work is finished

A licensed plumber does that paperwork as part of the job. Hang onto it. When you sell, the buyer's solicitor will ask whether the renovation work was done compliantly, and a missing certificate turns into a problem at the worst possible time.

How Can You Keep Bathroom Plumbing Costs Down?

Five things that genuinely make a difference to the bill:

1. Keep the layout close to what is already there. Every pipe that moves costs money. Leave the toilet, shower and vanity where they are and the rough-in cost drops a long way.
2. Choose your fixtures before the rough-in. The plumber sets the supply points and wastes to suit the actual fixtures, so changing your mind afterwards means opening the wall back up.
3. Buy the fixtures yourself. Plumbers put a margin on anything they supply. Buying your own taps, toilet and shower from a bathroom supplier will usually save you money, but run the models past your plumber first so you know they will fit what is there.
4. Get three quotes from licensed plumbers, and check each one covers the same scope. A cheap quote is often just a smaller quote.
5. Do not cut corners on the waterproofing. Whatever you save now, you will spend several times over when the shower starts leaking into the room below.