A bathroom reno needs the plumbing done twice: once before the walls are closed up, and again after the tiling is finished. When the order slips, people end up paying to pull tiles off a brand new wall. Here’s what happens on the plumbing side of a Perth bathroom renovation, in the order it happens.
Before anything comes out
Settle the layout
The biggest thing that drives plumbing cost is whether fixtures move. Waste pipes need a fall to drain properly, and in a lot of Perth homes the bathroom sits on a concrete slab, so moving a toilet, shower or floor waste can mean cutting into the slab to relocate the pipe. Keeping the toilet and shower where they are is the easiest way to keep the plumbing simple.
Pick your tapware and fixtures early
This one catches people out. Shower mixers and wall-mounted tapware have a body that goes into the wall at rough-in, and those bodies usually only work with the matching trims from the same range. The same goes for wall-hung toilets, which need an in-wall cistern and frame fitted before the wall is sheeted. If you haven’t chosen them by rough-in, the whole job waits.
The order of work
- Strip-out, where the old fixtures come out and the water and waste get capped off so the room can be stripped safely.
- Rough-in, where I run the new water and waste lines to suit the layout, set the shower and floor waste positions, and fit the mixer bodies and any in-wall cistern. I test everything before the walls close up.
- Waterproofing, which the waterproofer does, and which needs time to cure before tiling starts.
- Tiling, with the walls and floor tiled around the rough-in points.
- Fit-off, when I come back to fit the toilet, vanity, basin, shower and tapware, connect everything and check it all runs and drains properly.
The plumbing itself is only a small part of the reno’s calendar. Most of the time goes on waterproofing, curing and tiling, which is why booking the plumber in for the right stage matters more than how long the plumbing takes.
The paperwork
In WA, bigger plumbing jobs count as major plumbing work. For major work, the licensed plumbing contractor lodges a notice of intention with the regulator before starting and a certificate of compliance within five working days of finishing, and the owner or occupier of the property gets a copy. Ask your plumber whether your reno counts as major plumbing work, and make sure you get your copy of the certificate.
Timing tips
- Book the plumber when you book the builder or tiler, not after, so the rough-in lands before the walls need to close up.
- Have the tapware and fixtures on site, or at least chosen, before rough-in day.
- Leave the plumber’s rough-in points alone until fit-off. A mixer body knocked out of level shows up as a crooked trim later.
What I handle
I do all of the plumbing for a bathroom reno, start to finish: moving the water and waste lines, the rough-in before the walls close up, and the fit-off after the tiler. Because I’m there for both visits, whoever roughed it in is the one fitting it off, and you get a fixed price before any pipe is cut. More on bathroom renovations, or rough-in and fit-off for new builds and extensions.
Only swapping a vanity, toilet or tapware? That’s a smaller job. See taps and toilets.
Common questions
How long does the plumbing for a bathroom reno take?
It depends on how much is moving, but the plumbing is a small share of the total. The rough-in and fit-off are two separate visits with the waterproofing and tiling in between.
Do I need a licensed plumber to replace a vanity or toilet?
Yes. Any work that connects to your water supply has to be done by a licensed plumber in WA.
Can I save money by keeping the old layout?
Usually, yes. Leaving the toilet, shower and floor waste where they are avoids moving pipes and, on a slab, avoids cutting concrete.
Planning a bathroom reno? Send me the plans or a few photos and I’ll give you a fixed price for the plumbing.