The layout, and which wastes, toilets, showers and walls move
Moving a waste or a wall drives cost and every later stage.
Ask: Is anything that drains moving? Check the fall to the sewer before you commit.
Plan · Bathroom and ensuite · 47 decisions
Bathroom and ensuite: what to decide, and when
Every decision with a deadline for the bathroom and ensuite, in build order. Whole-house items are included.
Copies the decisions shown, with a prompt, to paste into ChatGPT, Claude or Gemini.
1
Design
Before anything is pulled out or ordered. Layout, what moves, and what has a long lead time. The cheapest stage to change your mind.
Shower type: step-down, level entry with a linear drain, or a hob
It sets how the floor is built and how deep the screed is.
Ask: Can the floor be set down, or do you need a hob or linear drain to get the entry you want?
Everything recessed: shaving cabinets, niches, cavity sliders, TV recesses
Each one needs framing, so it has to be known before the carpenter starts.
Ask: Which items sit in the wall rather than on it?
Order dates for long-lead items: custom joinery, imported tiles and tapware, stone
Some take weeks or months to arrive, longer than the gap to the stage that needs them.
Ask: What has a lead time longer than the time until it is needed?
Which NCC and state rules apply to your work
Livable housing rules, for example, apply differently by state and not at all in some. source
Ask: Have you asked your certifier or builder which rules apply to this job?
2
Framing
Before the carpenter frames or re-frames walls. Anything recessed or wall-hung. The carpenter frames to the actual product.
The recessed mirror or shaving cabinet: exact model, size and mounting height
The carpenter frames the opening to the product. A different cabinet later means re-framing.
Ask: Is the cabinet in hand, or its spec sheet final? The framer needs the real size, not an estimate.
Shower niche position and size
It is framed now and tiled later, so its size should suit whole tiles. source
Ask: Is the niche sized to whole tiles, clear of the mixer, and between studs? A common base height is 900 to 1100 mm. Choose it here
In-wall cistern frame model
The frame sets the pan height, the button height and the wall depth.
Ask: Which frame, and does it suit your pan and your wall depth?
Which vanities, toilets and cabinets are wall-hung
Wall-hung items need a frame or heavy blocking behind them.
Ask: What is hanging off the wall, and what does its install sheet ask for behind it?
Bath: freestanding or built-in, and a floor-mounted or wall filler
A floor-mounted filler can't be added once the floor is poured or screeded. source
Ask: If the filler comes up through the floor, is its position fixed now?
Door sizes and cavity sliders
Openings are framed now. Where livable housing rules apply, doors need an 820 mm clear opening. source
Ask: Which doors are sliders, and do the openings meet any rule that applies to you?
Window sill heights against benches, splashbacks, tapware and mirrors
A sill that clips the splashback or the tap is a framing fix, not a tiling one.
Ask: Does every sill clear the bench, splashback and taps under it?
3
Rough-in
Before the plumber and electrician run pipes and cables. Everything that sits in the wall or ceiling. Most variations start here.
Tapware type and brand for every wall mixer and spout
In-wall mixer bodies are brand-specific. The trim must match the body already in the wall.
Ask: Is the trim you want the same brand as the body going in now?
Shower: rail set or overhead arm, and the rose and mixer heights
The outlets are fixed in the wall. Roses usually sit 2000 to 2200 mm and mixers about 1000 to 1200 mm. source
Ask: Rail or arm? Have you set the heights from the finished floor?
Floor waste: point or linear, and where it goes
It sets the falls and should sit on the tile grid.
Ask: Will the waste land on a tile joint, and which way does the floor fall to it? Choose it here
Vanity top height and basin type (above counter, under counter, wall basin)
It sets the waste and supply heights, and the spout is set off the basin rim. Tops usually sit 850 to 900 mm. source
Ask: What height is the finished top, and how high is the basin rim above it?
Toilet pan and its set-out from the wall
Pans are set out at 140 or 165 mm from the wall. The waste is placed to suit the pan. source
Ask: Which pan, and which set-out does its install sheet give?
Hot water system type and location
It sets pipe runs and power or gas. Water at basins, baths and showers is limited to 50 degrees C. source
Ask: Where does the hot water unit go, and how far is the longest run?
Every power point, switch and light, including power inside joinery
Cables go in before the walls close. Power points are usually about 300 mm high and switches about 1000 to 1200 mm, by convention, not code. source
Ask: Have you walked each room with the furniture: bedsides, desk, TV, benches, robe, appliances?
What electrical items go near the shower and bath
AS/NZS 3000 sets zones around showers and baths that limit what can go where. source
Ask: Has your electrician checked every point near water against the wet-area zones?
Heated towel rail, LED mirror, shaving cabinet power and exhaust fan
Each needs a point at the height its install sheet gives, and the fan needs a duct.
Ask: Do you have the install sheet for each powered item?
Data, TV, air conditioning heads and drains, and smoke alarms
All run in the walls and ceiling. Smoke alarm rules differ by state.
Ask: Have you checked your state's smoke alarm rules, and where the AC drain runs?
4
Set-out and screed
Before the floor is screeded and the room is set out. Tile size, bedding depth and falls. Every height in the room is measured from the finished floor this sets.
Tile size and layout, at least in general
It sets the joint lines, the cuts and where the waste sits. You can pick the exact colour later.
Ask: Do you know the tile size, so the floor and the waste can be set out? Choose it here
Bedding and screed depth
Allow about 40 to 50 mm. It moves the finished floor, and every height in the room is measured from the finished floor.
Ask: Have you allowed 40 to 50 mm for bedding? Your heights are from the finished floor, not the slab.
Wall build-up: sheet, membrane and tile
About 15 to 25 mm is added to the wall face, which moves outlets, niches and set-outs. source
Ask: Have pipe and outlet depths allowed for the finished wall face?
Falls to the waste, and the entry into the shower
Wet-area falls are set by the NCC and AS 3740. Get them wrong and water sits or escapes. source
Ask: Have your tiler and waterproofer agreed the falls and the shower entry?
A finished floor level datum line, marked on the studs
Every fixture height is from the finished floor. Mark it once, then set out from it.
Ask: Is there a datum line on the studs before anything is set out?
Thresholds and floor transitions between rooms
Tile next to timber or carpet needs matching heights and a trim.
Ask: Do the finished floor levels line up at every doorway?
5
Waterproofing
Before the membrane goes on. Membrane heights and details. Can't be redone once tiled.
Membrane heights and junctions
Shower walls are waterproofed to at least 1800 mm (or 50 mm above the rose if higher), with 40 mm each side of wall junctions. source
Ask: Does your waterproofer's scope meet the NCC heights?
Puddle flanges at every waste, and the niche and hob details
These are the leak points, and they are buried once tiled.
Ask: Is every waste flanged, and is the niche sill falling back into the shower?
6
Linings
Before the walls and ceilings are sheeted. Blocking behind every fixing, and the plasterboard finish level.
Blocking behind every fixing: towel and grab rails, cabinets, shelves, TV, heavy mirrors, curtain tracks
Once the sheet is on, adding it means cutting the wall. Where livable housing rules apply, grab-rail walls need 12 mm ply or 25 mm noggings. source
Ask: Has every fixing point got blocking, photographed before sheeting?
Plasterboard finish level
Level 4 is standard. Gloss paint, dark colours and raking light need Level 5, which is set when the board is stopped, not painted. source
Ask: Are any walls going gloss, dark, or in raking light?
Wet-area board for walls and ceiling
Wet areas take a water-resistant board under the membrane and tile.
Ask: Is wet-area board specified for every wet wall?
7
Tiling
Before the tiler sets out. Tile heights, grout, trims and slip ratings. The tiler sets out from these on day one.
Tile heights: band, full height or skirting, wall by wall
The tiler sets out from these. Keep one skirting height on every wall; a height that changes is the first thing people notice.
Ask: For each wall: floor to where?
Grout colour and type: cement, epoxy or urethane
Pale floor grout tends to go grey; epoxy needs no sealing and suits showers but costs more.
Ask: Have you seen the grout beside the real tile, in the room's own light? Choose it here
Edge trims and their finish, or mitred edges
Trims show on every external corner and should match the tapware finish.
Ask: Which edges get a trim, and in what finish?
Mirror and cabinet heights against the tile line
Two trades meeting on one line shows every millimetre of tolerance. Keep the top of a mirror cabinet off the tile line, about 100 mm below it.
Ask: Do any edges from two different trades land on the same line?
Slip rating for every floor
P3 is the usual minimum for bathroom floors; P4 or P5 for outdoors, ramps and pool surrounds.
Ask: Does each floor tile carry a published P rating that suits where it goes? Choose it here
8
Joinery order
Before cabinets and benchtops are ordered. Measure what was built, not what was drawn, then lock boards, benchtops and appliances.
Benchtop material, thickness, edge and overhangs
The edge profile can move the price more than the colour does.
Ask: Which edge, which thickness, and where are the overhangs? Choose it here
Board colours and finishes, and handles or push-to-open
Boards are ordered with the cabinets.
Ask: Have you seen the board sample next to the benchtop and the floor? Choose it here
9
Painting
Before the painter quotes and starts. Colours, sheen, prep and coats, per surface.
Colours for each room and surface: walls, ceilings, trims, doors
The painter quotes per surface.
Ask: Have you put real samples on your own walls, in the room's light? Choose it here
Sheen for each surface
Ceilings are usually flat, walls low sheen, and wet areas, trims and doors semi-gloss or gloss.
Ask: Is the sheen written next to every colour in the painter's scope?
Prep and number of coats in the painter's scope
Quotes differ most on prep and coats. Master Painters recommend three coats on new work. source
Ask: Does every quote state the prep and the coats, so you can compare them?
10
Fit-off (can wait)
At the end. The choices you can safely leave late: positions are already fixed.
Light fittings
Positions were fixed at rough-in, so the fitting itself can be chosen late.
Ask: Do the fittings suit the points already in the ceiling?
Handles, towel rails, hooks and accessories
The blocking is already in, so these can wait.
Ask: Do the finishes match the tapware?
Shower screen and surface-mounted mirrors
Screens are measured after tiling.
Ask: Has the screen been measured off the finished tiles?
Window furnishings and loose furniture
Nothing else depends on them.
Ask: Did the power points land where the furniture went?
Prompts, not rules. Most choices can wait; these can't, because a later trade builds to them. Code items cite their source; states adopt parts of the NCC differently, so check yours. Your builder, trades, certifier and each product's install sheet decide. Download the list (JSON, CC BY 4.0).