Apartment Bathroom Renovation Process: What Actually Happens, Stage by Stage

Most bathroom process guides describe a house. An apartment is a different job, because you are working on top of someone else's ceiling, through a shared slab, under a strata by-law, and to a stricter waterproofing rule. This guide walks the real start-to-finish process for a Sydney apartment bathroom, stage by stage, with how long each part takes and the apartment-only realities that catch owners out. For what it all costs, see our separate apartment bathroom renovation cost guide.

What is the process for renovating an apartment bathroom?

An apartment bathroom renovation has six on-site stages that always run in the same order: strip-out, rough-in, waterproofing, screed and tiling, fit-off, and certification. The on-site work takes about 2 to 3 weeks. The order is fixed because each stage seals or covers the one before it, so a trade out of sequence means undoing finished work. Running before all of it is strata approval, which takes 6 to 12 weeks and has to be done first.

Durations are working days for a standard apartment bathroom and assume no major surprises in the slab or the pipes. Restricted strata work hours and membrane cure times are why the on-site total lands at 2 to 3 weeks rather than the one week a house bathroom can take.

Stage 0: Strata approval and the by-law (before any work)

Nothing starts until strata approval is in hand, and that takes 6 to 12 weeks. A bathroom renovation disturbs waterproofing and usually plumbing, which makes it major work under section 108 of the Strata Schemes Management Act 2015. Major work needs a special resolution at a general meeting, which means no more than 25 percent of the votes cast can be against it, and it usually needs a registered common-property rights by-law on top.

The by-law is the part owners underestimate. It has to be drafted, passed at a meeting, then registered with NSW Land Registry Services, which charges $175.70 to register it, on top of roughly $900 to $1,000 plus GST to a strata lawyer to draft it. The meeting cycle alone, getting an item onto an agenda and through a vote, is what stretches this to 6 to 12 weeks. The build is quick. The permission is slow, and it runs first.

See the full Sydney strata approval guide for the by-law process step by step.

Stage 1: Strip-out and demolition

Strip-out takes 1 to 2 days and clears the bathroom back to bare substrate. The old vanity, toilet, screen, tiles and wall linings all come out, and the existing waterproof membrane is removed with them. In an apartment this stage is shaped by access, not by the work itself. Every bag of spoil has to be carried out through the common lift, inside the hours the building allows, with the lift protected and the corridors covered.

This is also where older blocks reveal themselves. Pre-1990 Sydney units can hide asbestos in wall sheeting or floor backing, which has to be removed by a licensed asbestos remover before anything else proceeds. A good builder allows for that risk rather than discovering it on day one and stopping the job.

Stage 2: Rough-in, the slab and the common-property pipes

Rough-in takes 2 to 3 days and is where the plumber and electrician set everything that will later be buried: water lines, the floor and shower wastes, and the wiring for lights, fans and heated towel rails. In an apartment, this is the stage where the building fights back, because your bathroom sits on a concrete slab and your wastes connect to pipes that belong to the whole building.

Two apartment-only realities live here. First, the slab. Relocating a toilet or shower waste often means core-drilling through the concrete, and in a post-tensioned slab, common in Sydney towers built from the 1980s on, you cannot drill without an engineer's sign-off and a scan, because cutting a structural tendon is a serious and expensive failure. The simplest way to keep a bathroom renovation cheap and low-risk is to keep the wastes where they are. Second, the pipes. The stacks and risers your bathroom connects to are common property, so altering or connecting to them needs owners corporation consent, which is one more reason the by-law has to be right before work starts.

Stage 3: Waterproofing to AS 3740, the one stage you cannot get wrong

Waterproofing takes 2 to 3 days, and it is the most important stage in the whole job. The wet-area floor and the lower walls are sealed with a membrane, applied in two or three coats with curing time between each, and the membrane has to cure fully before any tile is laid. It is one of the cheapest line items in a bathroom and the single one that, done badly, leaks into the unit below and becomes your problem to fix in two apartments at once.

The rule is AS 3740:2021, the Australian Standard for waterproofing domestic wet areas, which the National Construction Code adopts. In practice it sets out what gets sealed and how:

• • The shower floor, including any hob or step-down, must be fully waterproof.
• • The shower walls must be waterproof to at least 1800 mm above the floor, or 50 mm above the shower rose, whichever is higher.
• • All wall and floor junctions, and every pipe penetration, must be waterproof.
• • The floor must fall to the waste, at a continuous grade between 1:80 and 1:50, so water actually drains rather than pooling.

One detail matters more in a unit than a house. The 2021 standard requires the membrane itself, not just the tiles on top, to be graded to fall to the waste, and apartments (Class 2 buildings) do not get the opt-out that a freestanding house can use. The membrane is the real waterproof layer. Grout and tiles are not waterproof, so if water gets through them it has to run across a graded membrane to the waste, not sit in a flat tray under your floor.

This is also why a $10,000 bathroom is a false economy in an apartment. A cheap quote hits that number by skimping on or skipping proper waterproofing, which is the exact part that, when it fails, costs you far more than you saved. For where the money actually goes, our apartment bathroom cost guide breaks it down, and our waterproofing guide goes deeper on the standard and the liability.

Stage 4: Screed and tiling

Screed and tiling take 4 to 6 days and turn a sealed shell into a finished bathroom. The floor is screeded to create the fall to the waste required by the standard, then the floor and walls are tiled and grouted. This is the longest stage because tiling cannot be rushed, the adhesive and grout need time to set, and large-format tiles take longer to lay level than small ones.

The apartment-only part is acoustic underlay. Most Sydney strata schemes require an acoustic membrane under hard floors and tiles to meet the building's noise rating, so the unit below does not hear every footstep and every drain. The underlay is laid as part of the floor build-up, and the by-law often names the rating it has to meet. Skipping it is a common reason a renovation passes the owner but fails the neighbour, and then the owners corporation.

Stage 5: Fit-off

Fit-off takes 2 to 3 days and is the stage that finally looks like a bathroom. The vanity, toilet, tapware, shower screen, mirror, towel rails and accessories are installed and connected, the plumber commissions the water and checks for leaks, and every wet junction is sealed with silicone. It is fast and satisfying, and it is only as good as the three stages buried underneath it.

Stage 6: Certificates and sign-off

The final 1 to 2 days are about paperwork, and in an apartment the paperwork is the point. The licensed waterproofer issues a waterproofing certificate confirming the work meets AS 3740, the plumber issues a certificate of compliance for the plumbing, and copies go to you and to the owners corporation. Because the waterproofing liability now sits with your lot, these certificates are what prove the work was done properly if a leak is ever raised years later. A renovation without them leaves you exposed on the one risk an apartment bathroom carries that a house does not.

On-site work is 2 to 3 weeks, but owners often quote a longer total because they are counting the strata approval and the lead time on fixtures and tiles. The build is the short part. Plan the approval and the ordering first, and the on-site weeks look after themselves.

Frequently asked questions