Bathroom Renovation Mistakes to Avoid

By the Baroco team, Mount Waverley · Updated October 2026

01Get the exhaust fan sizing right

Many Melbourne bathrooms are fitted with a small axial fan that is barely bigger than a computer fan. It might clear a tiny powder room, but it will not shift the steam from a family shower. Undersized exhaust fans leave moisture on the ceiling, walls and grout, which encourages mould, peeling paint and musty smells.

An electrician can size the fan to the room volume and required air changes. The ducting must run to outside air, never into the roof space or ceiling cavity. A run-on timer that keeps the fan going for ten or fifteen minutes after the light goes off makes a significant difference in colder months when windows stay shut.

If the bathroom has a separate shower and toilet, or the ceiling is low, consider an inline fan or a second extraction point. The extra cost is small compared with repairing water damage or repainting a ceiling every few years.

• Match fan capacity to room volume, not just the hole in the ceiling.
• Duct to the outside, never into the roof space.
• Install a run-on timer or humidistat for Melbourne's damp winters.

02Don't let poor floor falls ruin the shower

The shower floor should fall steadily towards the waste, with no flat spots or low edges. If the screed is a little out, water ponds in the corners and takes hours to evaporate. That constant dampness makes the floor slippery and keeps the grout dark.

A good tiler sets the falls before laying tiles and checks the slope with a spirit level as they go. The waterproofing underneath needs a puddle flange that sits flush with the finished floor level, so water that gets past the tile can still drain. If the membrane is higher than the surrounding floor, it holds water instead of shedding it.

For open showers without a hob, the fall is even more important because water can spread across the whole bathroom floor. Decide the waste position and screen layout before the screed goes down, not after the tiles arrive.

• Test the finished shower with a jug of water to check for ponding.
• Make sure the puddle flange and membrane work with the fall.
• Use smaller tiles on shower floors if a consistent slope is hard to achieve.

03Choose tiles for wet areas, not just looks

Polished porcelain looks great in a showroom, but it can be dangerous under wet feet. For bathroom floors, choose a tile with a slip resistance rating that suits wet barefoot traffic. Gloss or high-sheen tiles are better kept to walls, splashbacks or areas you do not walk on.

Large-format tiles have fewer grout lines, but they are harder to lay with correct falls in a shower. If the tile is too large for the floor area, there is a risk of lippage and water pooling between the high spots. A mosaic or smaller tile in the shower base lets the installer create a smooth, even slope.

Think about maintenance too. Light-coloured matte tiles tend to hide soap scum and water spots better than dark gloss. Grout colour also matters; a mid-grey or warm tone ages better than stark white in a wet shower.

• Check the tile's slip resistance rating before buying.
• Use mosaic or small-format tiles inside the shower base.
• Avoid polished or high-gloss tiles on bathroom floors.

04Plan storage early, not as an afterthought

A bathroom with no storage becomes a cluttered shelf of bottles and folded towels on the floor. Plan storage during the design phase, before walls are sheeted, so you can include recessed niches, a mirrored cabinet or a vanity with drawers rather than a single cupboard.

A shower niche keeps shampoo and soap off the floor and is easier to clean than a wire basket. If you choose a wall-hung vanity, make sure there is still a place for spare toilet paper, cleaning products and the hairdryer. A tall storage cabinet beside the basin is often more useful than a large mirror.

For small bathrooms, built-in storage works better than open shelves. Recessed wall cabinets take up no floor space and keep the room looking calmer.

05Sort out lighting and electrical positions before tiling

Bathroom lighting should be planned in layers. A single centre ceiling light leaves your face in shadow at the mirror, which makes shaving or applying makeup difficult. Task lighting either side of or above the mirror, plus a separate IP-rated light in the shower, makes the room safer and more pleasant.

All electrical work in a bathroom must be carried out by a licensed electrician, and the fittings need to be rated for the zone they are in. Cables and conduits should be roughed in before tiling starts, because moving a light or adding a power point later means cutting into finished tiles.

If you want a heated towel rail or underfloor heating in the future, run the wiring now. It is far cheaper to install a cable behind the wall before tiling than to retrofit it later.

• Plan task lighting at the mirror and a separate shower light.
• Check IP ratings for fittings near water.
• Rough in wiring for heated towel rails and underfloor heating early.

06Don't cheap out on tapware cartridges or rush waterproofing

Cheap tapware often fails at the cartridge, the working part inside the handle. A poor-quality ceramic or plastic cartridge wears out quickly, causing drips, stiff operation or sudden temperature changes. When it fails, you may struggle to find a replacement, and the whole mixer may need replacing if the brand has no spare parts.

Waterproofing is the one stage you cannot afford to rush. The membrane must be applied by a licensed waterproofer to the walls and floor in line with AS 3740, including all corners, junctions and pipe penetrations. It has to cure fully before tiles are laid, and any thin spots or damage must be repaired first.

Rushing waterproofing to keep the renovation on schedule is a false economy. Water that gets behind tiles or into the floor structure will rot timber, damage plaster and create ongoing mould problems that no amount of bleach will fix. If you are planning a Melbourne renovation, comparing tapware, tiles and storage options in person can prevent these mistakes. Baroco Interior Innovations has a showroom at 21/105-111 Ricketts Road, Mount Waverley where you can check products and talk through your layout; call ahead before visiting.

• Choose tapware from a brand that stocks replacement cartridges.
• Insist the waterproofing is inspected before tiling starts.
• Let the membrane cure properly; do not tile over wet or damaged areas.