Most bathroom renovation problems come from two places: planning decisions made too late, and wet-area work done poorly behind the tiles. This guide walks through the renovation in order and shows where things most often go wrong.
Step 1: Plan the layout and budget
Decide what the bathroom needs: shower or bath (or both), single or double vanity, storage, and who will use it. Keeping the toilet and shower where they are is the biggest single saving. Set a budget with a 10–15% contingency, because older Sydney bathrooms often hide rotten framing or old leaks. See our bathroom renovation cost guide for current prices.
Step 2: Choose fixtures and finishes before work starts
Select tiles, tapware, vanity, toilet and shower screen before demolition. Some items take weeks to arrive, and late changes delay every trade after them. For help choosing, see our guide to the best bathroom materials.
Step 3: Check approvals and licences
In a house, replacing a bathroom without changing the structure usually doesn’t need council approval. Apartments need owners corporation approval first. In NSW, waterproofing work valued over $5,000 must be done or supervised by a licensed waterproofer, and plumbing and electrical work must be done by licensed trades (NSW Government).
Step 4: Demolition and rough-in
Once the old bathroom is stripped, the floor and wall framing are checked and repaired. Plumbing and electrical are roughed in, and any new niches, wall-hung frames or exhaust fans go in at this stage.
Step 5: Waterproofing done properly
Waterproofing is the most important part of a bathroom, even though you never see it. It’s done to Australian Standard AS 3740 and must be finished and cured before tiling. A good waterproofing job includes:
- Correct falls in the shower floor so water drains to the waste, not across the floor
- A waterproof membrane over the full shower area and floor, with bond breakers and flashings at wall-floor joints
- Proper sealing around penetrations such as taps and wastes
- Enough curing time before tiles go on
Sydney’s humidity makes good ventilation just as important. A ducted exhaust fan vented outside, not into the roof space, helps prevent mould.
Step 6: Tiling, fit-off and handover
Tiles go down after waterproofing has cured, then the vanity, toilet, screen, tapware and accessories are installed. Silicone joints are finished last. Ask for your waterproofing certificate and product warranties at handover.
The most common bathroom renovation mistakes
- Cutting corners on waterproofing. Leaks can damage framing and ceilings for years before anyone notices.
- Poor drainage falls. Water pooling on the shower floor or flowing out of the shower is a sign of incorrect falls.
- No ventilation, or venting into the roof. This leads to mould and damp in Sydney’s humid climate.
- Too little storage. Plan a vanity with drawers, a shower niche and a mirrored cabinet.
- Choosing finishes late. Delays and changes mid-job are where costs blow out.
- Slippery floor tiles. Choose tiles with a suitable slip rating for wet areas.
- Using unlicensed trades. It can void insurance and leave you without protection if something fails.
Plan your bathroom with Blackwood
Blackwood Carpentry & Joinery manages bathroom renovations from design to handover across Sydney’s North Shore, Northern Beaches, Eastern Suburbs and Inner West. We coordinate licensed trades and build custom vanities and storage. NSW Lic. 502666C.
See our bathroom and laundry renovations or call Fred on 0478 900 078.
Frequently asked questions
What is the most important part of a bathroom renovation?
Waterproofing. It protects the structure of your home and is very costly to fix if done badly.
Does waterproofing need a licensed tradesperson in NSW?
Yes, for waterproofing work valued over $5,000. It should be done to AS 3740 and come with a certificate.
How long does a bathroom renovation take?
Usually 3–6 weeks on site, including curing time for waterproofing.
What’s the most common bathroom renovation mistake?
Rushing or skimping on waterproofing and drainage falls.