How to Tile a Bathroom: DIY Step-by-Step Guide

Q: Can existing tiles be tiled over rather than removed?

It&#39;s technically possible if the existing tiles are fully bonded, flat, and the added height won&#39;t cause problems at doorways or fixtures — but any hollow or loose tiles underneath will telegraph movement straight through to the new surface. Most experienced renovators pull them off entirely; the prep work you save rarely outweighs the risk of a failed finish two years later.

Description: A complete beginner's guide to tiling and grouting a bathroom floor, covering tools, adhesive application, tile laying, cutting, spacing, and grouting — ideal for Australian DIYers tackling a bathroom
Video Credit: The DIY Guy

Tile a bathroom, and it all looks pretty straightforward on a renovation TV programme. Get in a wet room once the old tiles have been ripped out, and you're suddenly holding a notched trowel and wondering what you've got yourself into. I've seen both sides of the story, as a plumber for years, seeing tilers work around me, and in my writing career, learning from years of research and hands-on knowledge on what makes a tiled bathroom stand the test of time. So, how to tile a bathroom correctly? The truth is, preparation is all you need.

What You'll Need: Tools, Materials & Costs

First, get all the material and tools ready before you begin. What you'll need includes tile adhesive, a notched trowel, a grout float, tile spacers, a spirit level, a measuring tape, a pencil, a bucket, and a wet saw or a score-and-snap tile cutter. You may also want knee pads and safety glasses, as they do actually come in useful.

As for the materials, what type of tile you use matters. Ceramic is one of the cheapest tiles at $12–$47 per piece, and they're best to use on walls. Porcelain tiles are fired at a higher temperature and have less porosity, making them more resilient; they cost between $6–$698 per piece, depending on the style and size. If you're tiling the floor, you'll need to make sure it meets the P-rating requirements for wet areas as per AS 4586. Polished tiles shouldn't be used on the floor and should be wall tiles only.

For professional tile laying, labour runs $50–$70 per m² (HIA Bathroom Renovation Cost Guide 2025) as a market benchmark — you're saving a fair chunk of change by doing it yourself, but you're also taking on a big job to boot. Most DIY bathroom floor areas average 8–10 m², so factor that into your planning.

And lastly, regarding cost, large-format tiles (600×1200mm) require a very flat surface and a high level of skill to lay with no lippage. I'd advise any DIYer to avoid them.

Cross-section diagram of bathroom wet area waterproofing membrane, flashing, and substrate layers

Bathroom Waterproofing: The Non-Negotiable First Step

With the tools and materials in place, you need to waterproof the substrate before you put the first tile on the walls or floor. This is required by Australian standards for wet areas.

Bathroom waterproofing is not to be overlooked and is definitely not a quick job. Shower walls must be waterproofed to a minimum of 1800mm (AS 3740:2021) (NCC 2022, ABCB Housing Provisions, Part 10.2) above the floor substrate. Bath-adjacent walls need to be waterproofed to 150mm above the bath rim. And the wall-to-floor junction must be protected with a flashing with a horizontal leg of no less than 40mm.

Those aren't just guidelines — in most Australian states, waterproofing in wet areas must be completed by a licensed waterproofer — not a DIYer. This is a compliance requirement, not a suggestion. After application, you can begin tiling once the waterproofing membrane has cured, which takes 24–72 hours depending on the product used. The full renovation timeline from membrane application to final silicone bead typically runs five to seven days. Skipping or cutting short any part of the waterproofing process is the main cause of tile failure and structural water damage that I witness as part of a renovation job.

Tiler in gloves laying large grey stone tile onto ridged adhesive floor bed

Laying Your Tiles: Cutting, Spacing & Adhesive Application

When the waterproofing membrane has fully cured, the substrate is ready to accept tiles — and the method you use to plan the layout and apply the adhesive will determine whether the finished result looks professional or amateurish.

The best place to start is from the centre point of the floor or wall and work outward from there. This is one of the key bathroom renovation steps that inexperienced tilers skip, and it shows — you end up with slivers of tile in prominent corners. Snap chalk lines through that central mark to establish your grid.

Mix tile adhesive to a smooth, lump-free consistency and apply it with a notched trowel, combing ridges in a single direction. For tiles larger than 300×300mm, back-butter the tile as well — this ensures full adhesive coverage and prevents hollow spots. Set your spacers as you go: 1mm joints for a seamless look, 2–3mm for a more traditional finish. Check for lippage regularly with a straight edge. Adhesive needs 24 hours to cure before grouting begins.

Gloved hand spreading dark grey grout across concrete floor with red trowel

Grouting, Sealing & Finishing the Tiled Surface

Now that your adhesive has cured completely and all tiles are seated, it's time to begin grouting and sealing the surface. This is the final stage to ensure full waterproofing of the shower or wet-area walls, and to finalise the look of the tiled surface.

Prepare grout to a stiff consistency and apply using a rubber grout float angled at 45 degrees, packing the material diagonally into the grout joints. Scrape away excess grout before it begins to dry — the window for removing the haze correctly must be exact: wipe too early and you strip your joints of grout; wipe too late and you'll spend an hour scrubbing your tiles clean. Bathroom grout cleaning is an integral part of this stage, so prepare for the job with a wet sponge, cleaning the tiles with small circular motions and frequently rinsing the sponge to lift away the grout haze cleanly.

Allow grout to cure for 24 hours, then apply a water-resistant sealer to the grout joints and any natural stone tiles. At internal angles and the tub corner, use silicone sealant rather than grout. Grout is liable to crack as the building flexes at joints; silicone will not.

Cracked grout line along white bathroom wall tiles near bathtub edge

Common Tiling Mistakes and How to Avoid Them

Even after grouting and sealing, it's worth running through the following common DIY tiling errors — many can only be spotted now but may have been caused by an earlier decision.

Insufficient bathroom waterproofing. This is the most costly and critical failure. Ensure you engage a licensed waterproofer.

Uneven substrate. Tiles applied over a non-flat surface will crack. Ensure the surface is flat to within 3mm over 3m per AS 3958.1, and rectify with rendering if needed.

Wrong adhesive for the application. Wall tiling adhesive differs from floor tiling adhesive — always check the manufacturer's product data sheet.

Inadequate layout planning. Failing to find and centre on the wall's centre point means awkward cuts in visible positions.

No movement joints. AS 3958.1 requires movement joints at regular intervals and around all internal corners. Omitting them allows rigid grout to crack as walls flex.

Corner geometry. Corner baths and other bath configurations introduce additional angles that require careful tile cutting and silicone work at every corner bath junction. Plan these cuts before tiling commences.

Knowing how to tile a bathroom means understanding when to call in a licensed tradie. Waterproofing requires a licensed waterproofer, and plumbing reconnections — taps, waste, and shower fittings — require a licensed plumber under state plumbing licensing legislation. Knowing how to tile a bathroom can be a rewarding DIY project, but achieving a result that lasts 20 years demands patience in preparation, planning, and knowing where the licensed work begins.

References

HIA (Housing Industry Association) — Bathroom Renovation Cost Guide 2025

National Construction Code 2022, ABCB Housing Provisions, Part 10.2 Wet Areas

AS 3740:2021 Waterproofing of Domestic Wet Areas, Standards Australia

State plumbing licensing legislation (VBA Victoria; Fair Trading NSW; QBCC Queensland; Building Practitioners Board WA; CBOS Tasmania; ACTPLA ACT; Building & Energy SA; ABPB NT)

FAQs

How long should a DIYer realistically set aside for a full bathroom tiling project?

For an average bathroom of around 8–10 m², budget a full weekend for laying tiles alone — that's not counting the waterproofing cure time beforehand or the 24-hour adhesive set before grouting. Spread across a typical renovation timeline, you're looking at five to seven days from membrane application to final silicone bead, assuming no rework.

Can existing tiles be tiled over rather than removed?

It's technically possible if the existing tiles are fully bonded, flat, and the added height won't cause problems at doorways or fixtures — but any hollow or loose tiles underneath will telegraph movement straight through to the new surface. Most experienced renovators pull them off entirely; the prep work you save rarely outweighs the risk of a failed finish two years later.

What's the best way to keep grout lines looking clean long-term?

A penetrating sealer applied annually to grout lines makes a genuine difference, as does switching to an epoxy grout in high-splash zones like the shower floor — epoxy is non-porous and resists staining far better than cement-based grout, though it demands faster, more precise application.