A bathroom renovation is the most complex domestic renovation project in terms of trade coordination. Plumbing, waterproofing, tiling, electrical, and cabinetry all intersect in a small space, and the sequence matters enormously. Getting it right produces a beautiful, functional bathroom that lasts decades. Getting it wrong means expensive rectification.
What Plumbing Is Involved in a Bathroom Renovation?
A full bathroom renovation typically involves: relocating or replacing drain positions (shower, bath, basin, toilet), rerouting or replacing hot and cold supply pipes, fitting new isolation valves for all fixtures, rough-in to new fixture positions, and fit-off with new tapware, mixer, showerhead, toilet, vanity, and bath. If the bathroom is on a suspended timber floor (common in older Melbourne homes), drain routing can be done from below without cutting the floor. Concrete slab bathrooms require saw-cutting for any drain changes.
The Renovation Sequence
The correct sequence for a bathroom renovation is: strip-out (remove all old fixtures, tiles, and linings) → plumber rough-in (new drain and supply positions) → waterproofer (membrane to all wet areas) → tiler → cabinetry/vanity installation → plumber fit-off (connect all fixtures) → electrician (lights, exhaust fan, heated towel rail). Any deviation from this sequence typically causes problems — most commonly, waterproofing applied after tiling, which is a waterproofing failure waiting to happen.
Moving the Toilet: What It Involves
Moving a toilet is one of the most impactful changes in a bathroom renovation — and one of the most expensive plumbing components if moving any significant distance. The toilet drain (soil pipe) must maintain a minimum fall to the sewer. Moving a toilet more than about 300mm usually requires significant drain rerouting. Your plumber should assess this before you commit to a new layout that assumes the toilet can move freely.
What Does Bathroom Renovation Plumbing Cost in Melbourne?
Plumbing costs for a full bathroom renovation (rough-in and fit-off, existing layout maintained) typically run $2,500-$4,500. Renovations involving significant drain relocation, concrete cutting, or complex pipe rerouting run $4,000-$8,000+ for plumbing alone. These costs are separate from tiling, waterproofing, cabinetry, and other trades.
Key Planning Questions
Before committing to a bathroom renovation layout, confirm with your plumber: Can the drain positions stay approximately where they are, or will we need to cut concrete? Where does the current soil pipe run, and how does that constrain toilet placement? Is the existing water supply copper or PEX, and is it in good condition? Are there any asbestos-containing materials in the wall lining that need to be managed? Getting these answers early prevents expensive surprises mid-renovation.
Sedcon Plumbing — Bathroom Renovation Plumbing Across Melbourne
We provide full bathroom plumbing services throughout Melbourne, from complete renovations to single fixture replacements. Call 0468 013 012 to discuss your project.