Whether you’re renovating a bathroom, kitchen, or laundry, plumbing is one of the most critical — and most expensive — parts of the project. Getting it right from the start saves money, avoids delays, and ensures everything works properly for years to come.

Involve Your Plumber Early

This is the number one tip. Too many homeowners design their renovation and then bring in a plumber to make it work. By that point, design choices may be difficult or expensive to accommodate.

A plumber should be consulted during the planning phase — before tiles are chosen, before cabinetry is ordered, and before demolition begins.

Early involvement helps with:

• Fixture placement — Where taps, drains, and toilets can realistically go based on existing pipe locations
• Hot water capacity — Whether your system can handle additional fixtures
• Drainage fall — Ensuring waste water can flow to the sewer line
• Budget accuracy — No nasty surprises when the plumber starts work
• Timeline — Plumbing rough-in must happen before tiling, waterproofing, and cabinetry

Understanding the Plumbing Stages

Renovation plumbing happens in phases:

1. Strip Out

Removing existing fixtures, pipes, and fittings. This is when hidden problems are often discovered — corroded pipes, failed waterproofing, asbestos materials, or non-compliant previous work.

2. Rough-In (First Fix)

Installing new pipes for water supply and drainage in their new positions. This happens while walls and floors are open, before plastering, waterproofing, and tiling.

This is the most important stage. Mistakes in the rough-in are expensive to fix later because they’re hidden behind finished surfaces.

3. Waterproofing

In wet areas (showers, bathrooms), waterproofing is applied after the rough-in and must be inspected before tiling. In Victoria, waterproofing must comply with Australian Standards and be applied by a licensed tradesperson.

4. Fit-Off (Second Fix)

Installing the visible fixtures — taps, mixers, toilet, basin, showerhead, dishwasher connections, etc. This happens after tiling, painting, and cabinetry are complete.

Common Renovation Plumbing Mistakes

Moving Fixtures Too Far from Existing Pipes

Every metre you move a toilet, sink, or shower from its current position adds complexity and cost. Drainage in particular needs adequate fall to the sewer line — and sometimes the existing pipe layout makes certain positions impractical.

Choosing Fixtures Before Consulting a Plumber

That beautiful freestanding bath or wall-hung toilet might need specific plumbing configurations that add significant cost. Check with your plumber before committing to fixtures.

Skipping Waterproofing Inspection

Waterproofing in wet areas must be inspected before tiling. Skipping this step means you won’t know if the waterproofing is adequate until water starts leaking through — at which point the tiles need to come off.

Not Upgrading Old Pipes

If you’re opening up walls anyway, it’s the perfect time to replace old pipes. Closing up walls over corroded galvanised pipes means you’ll be opening them up again in a few years when they fail.

Underestimating the Timeline

Plumbing rough-in needs to be completed and inspected before waterproofing, which needs to be completed and inspected before tiling. Each stage needs to cure or dry. Rushing this sequence causes problems.

What Needs a Plumbing Permit?

In Victoria, plumbing work requires a compliance certificate. Your plumber handles this, but be aware that:

• All new plumbing installations need a certificate
• Relocating fixtures requires a certificate
• Connecting to or modifying the sewer line requires a certificate
• The work may need inspection by the VBA or a licensed building surveyor

Your plumber will advise on what’s needed for your specific project.

Questions to Ask Your Renovation Plumber

Before hiring a plumber for your renovation:

• “Can you work with my builder’s timeline?”
• “Have you done similar renovation work before?”
• “Can you advise on fixture selection?”
• “Will you handle the compliance certificate?”
• “What’s the rough-in timeline?”
• “Are there any issues with the existing plumbing we should know about?”

Hankook Plumbing Renovation Services

We work with homeowners and builders across Melbourne’s eastern suburbs on kitchen, bathroom, and laundry renovations:

• Design consultation — Advising on practical fixture placement
• Strip out and rough-in — Professional pipe installation
• Hot water upgrades — Ensuring your system meets increased demand
• Fixture fit-off — Installing all final fixtures
• Gas fitting — For cooktops and gas hot water
• Compliance certificates — All paperwork handled

Planning a renovation? Call 0407 756 172 early to get the plumbing right from the start.