Tiling a Bathroom — The Complete Guide to Walls, Floors and Wet Areas

Tiling a bathroom is one of the most technically demanding tiling jobs you'll do — and one of the most consequential. A badly tiled bathroom doesn't just look bad; it leaks. And water damage behind tiles in a bathroom is one of the most expensive building defects to fix. Here's how to get it right from the start.

Understand the Wet Area Rules First

In Australia, wet areas in bathrooms (shower recesses, around baths, and floor areas) must be waterproofed in accordance with AS 3740 — the Australian Standard for waterproofing of domestic wet areas. This is not optional. As a tiler, you need to understand this standard and apply it correctly.

• Shower recess walls: Waterproofing must extend to 1500mm above the shower floor on all walls within the shower, or 25mm above the finished height of any fixed shower screen.
• Shower floor: Full waterproofing coverage.
• Adjacent floor areas: 150mm beyond the shower threshold onto the bathroom floor.
• Around the bath: 100mm above the bath rim on adjacent walls.

Sequence Matters — Floor or Walls First?

This is one of the most debated questions in bathroom tiling. The professional answer depends on the situation, but here's the general approach:

• In shower recesses: Tile the floor first, then tile the walls down onto the floor tiles. This creates a waterproof junction at the floor-wall junction and means wall tiles shed water onto the floor rather than behind it.
• In the main bathroom floor: Tile after the walls — this way you can trim the floor tiles neatly to the wall tiles rather than having to cut wall tiles around floor tiles.

Whatever sequence you use, always leave the floor-to-wall junction sealed with silicone rather than grouted — this is a movement joint that must flex.

Choosing the Right Tiles

Not all tiles are suitable for all bathroom applications. Key considerations:

• Slip resistance: Shower floors and bathroom floors must have a minimum slip resistance rating of P3 (or R10 equivalent for commercial applications). Always check the slip rating.
• Tile size and format: Large format tiles (600x600mm and above) can look stunning but create challenges in shower recesses — particularly around falls to the drain. Smaller mosaic tiles (typically 50x50mm or similar) are often used on shower floors as they conform more easily to the fall.
• Rectified vs non-rectified: Rectified tiles are cut to precise dimensions and can be laid with very fine grout joints (as small as 1.5mm). Non-rectified tiles have natural size variation and need wider joints to accommodate this.

Setting Out in a Bathroom

Bathrooms are full of obstacles — shower niches, drains, toilet pans, vanities, doors — and setting out your tile layout to minimise awkward cuts and maximise the visual impact of the finished result is a real skill.

• Centre the feature wall of the shower — typically the back wall — and work symmetrically from the centre out.
• Check whether fixtures like towel rails and toilet roll holders will fall into the centre of a tile (ideal) or on a grout joint (try to avoid).
• For floor tiles in a wet area, set out so the fall to the drain is even across all tiles — this requires careful planning of your tile layout relative to the drain position.

Waterproofing the Shower Recess

The waterproofing membrane is your most important investment in a bathroom tiling job. Products like Mapei Mapelastic, Weber's Weberprim or Ardex WPM 300 are commonly used in NSW. Apply as per manufacturer specification — typically:

1. Apply fibreglass reinforcing tape to all internal corners and floor-wall junctions before membraning.
2. Apply membrane at minimum 2 coats, allowing each coat to cure fully before the next.
3. Cover all penetrations (drain outlets, pipes) with additional membrane material.
4. Allow full cure time before tiling.
5. Check thickness — most products specify a minimum wet film thickness of 1mm.

Grouting and Sealing Wet Areas

In wet areas, use a flexible, water-resistant grout — epoxy grouts offer the best performance in heavily used showers but are more difficult to work with. Standard cement-based flexible grouts (with water-resistant additive) work well for most residential bathrooms.

Seal cement-based grout in wet areas every 12 months — this is particularly important on shower floors where grout joints are exposed to constant water.

Common Bathroom Tiling Mistakes

• Skipping or rushing the waterproofing — the most expensive mistake in tiling
• Using wall tile adhesive on the shower floor — it doesn't have the strength for foot traffic
• Grouting the floor-wall junction instead of silicone — will crack within months
• Poor fall to drain — standing water in the shower is both unhygienic and damages grout faster
• Not accounting for the fall when setting out floor tiles — creates uneven grout joints
• Incorrect tile slip ratings on shower floors — both a safety and compliance issue

Ready to Master Wet Area Tiling?

Wet area waterproofing and bathroom tiling are core competencies in the CPC31320 Certificate III in Wall and Floor Tiling. At Wyatt Education Group, our practical training covers all aspects of wet area compliance — preparing you for real-world tiling work from day one.