The 10 Most Common Tiling Mistakes — And How to Fix Them Before They Cost You

Every tiler — professional or otherwise — has a collection of mistakes they'd rather forget. The difference between a tradesperson and a craftsperson is not that one never makes mistakes; it's that one knows how to identify them early, fix them properly, and avoid repeating them. Here are the ten most common tiling mistakes we see — and exactly what to do about them.

Mistake 1 — Skipping Substrate Preparation

What happens: Tiles de-bond, crack, or crack the adhesive layer due to a substrate that's too flexible, contaminated, or uneven.

The fix: Remove de-bonded tiles, prepare the substrate properly (level, prime, allow to cure), and re-tile. There is no shortcut — if the substrate isn't right, the tiling will fail.

Prevention: Always assess the substrate before starting. Check for flex, flatness, cleanliness, and moisture. Apply bonding primer on concrete substrates.

Mistake 2 — Insufficient Adhesive Coverage

What happens: Hollow tiles, tile cracking under point loads, tiles de-bonding at edges. AS 3958.1 requires minimum 95% adhesive coverage in wet areas and 80% in dry areas — most tiling failures involve inadequate coverage.

The fix: Re-tile affected areas. To check coverage on an existing installation, remove a tile and inspect the back — you should see adhesive covering the vast majority of the tile back with an even, consistent pattern.

Prevention: Use the correct notched trowel size for your tile. Back-butter large format tiles. Work in manageable sections. Press tiles firmly and use a slight twisting motion when bedding.

Mistake 3 — Wrong Adhesive for the Application

What happens: Wall tile adhesive used on a floor breaks down under load. Standard adhesive used in a pool dissolves. Rapid-set adhesive used in summer heat skins over before tiles are placed.

The fix: Strip and re-tile with the correct product. Adhesive selection is not optional — read the technical data sheet and match the product to the application.

Prevention: Always check: substrate type, tile type, application (wet/dry, interior/exterior, floor/wall, vehicular/pedestrian), and working conditions (temperature, humidity). When in doubt, call the adhesive manufacturer's technical support line.

Mistake 4 — Tiles Not Level or Plumb

What happens: A tiled wall or floor that looks fine at individual tile level but graduates visibly out of level across the room. Or worse — a feature wall where the tiles are noticeably tilting.

The fix: In extreme cases, re-tiling is the only solution. For minor issues, a skilled tiler can sometimes "rescue" a job by using slightly thicker adhesive beds on one side — but this has limits and is never ideal.

Prevention: Establish datum lines at the start using a laser level — not just a short spirit level. Check level across every 3–4 tiles as you go. It takes much less time to check and correct as you go than to re-tile a completed section.

Mistake 5 — Lippage (Tiles Not Flush)

What happens: Adjacent tiles sit at different heights, creating a raised edge that's both visually jarring and a trip hazard. Lippage is particularly obvious with large format tiles and rectified tiles with fine grout joints.

The fix: Minor lippage can sometimes be ground down with a diamond grinding pad, but this is a skilled operation and may be visible after grinding. Significant lippage usually requires re-tiling.

Prevention: Use a tile levelling system (clips and wedges) for tiles over 300mm. Back-butter all tiles to ensure even adhesive support. Never start tiling until the substrate is flat to within 3mm over 3m.

Mistake 6 — Grout Joint Inconsistency

What happens: Grout joints that vary in width across the installation — particularly visible in large-scale wall applications and feature walls where the eye naturally follows grout lines.

The fix: Re-grouting won't fix the joint width — that's set by the tile position. In extreme cases, the tiles need to be re-laid. For minor variation, a uniform grout colour can minimise the visual impact.

Prevention: Use tile spacers consistently. Check that spacers are the same size throughout — mixing 2mm and 3mm spacers in the same installation is a common cause of this problem.

Mistake 7 — Grouting Before Adhesive Has Cured

What happens: Grout cracks, adhesive doesn't achieve full strength, tiles shift slightly during grouting, creating grout joint variation.

The fix: Remove the grout (with a grout rake or oscillating multi-tool), allow the adhesive to cure fully, then re-grout.

Prevention: Read the adhesive technical data sheet — cure times vary significantly between products and depend heavily on temperature and humidity. Standard flexible adhesives typically need 24 hours at 20°C. In winter or in wet conditions, allow more time.

Mistake 8 — Using Grout Instead of Silicone at Movement Joints

What happens: Grout at internal corners, floor-to-wall junctions, and around fixtures cracks within months — often within weeks in high-movement areas.

The fix: Rake out the cracked grout and replace with flexible silicone sealant that matches the grout colour.

Prevention: Never grout movement joints. Every change of plane (floor to wall, wall to wall at internal corners) and every junction with a fixed element (bath, vanity, shower screen) must be sealed with flexible silicone.

Mistake 9 — Poor Grout Cleaning Leaving Haze

What happens: A cloudy, dull film over the tile surface that makes an otherwise good tiling job look dirty and unfinished. Grout haze is cured grout that wasn't cleaned off before it hardened.

The fix: For fresh haze (within 24 hours), warm water and a clean sponge can remove it. For hardened haze, use a purpose-formulated grout haze remover (follow instructions carefully — some are acidic and can damage certain tile finishes). For epoxy grout haze, you need an epoxy-specific remover.

Prevention: Don't let grout sit on the tile surface too long. Work in sections. Clean thoroughly with a well-wrung sponge and change your water frequently. Buff the tile surface with a dry cloth before the grout fully hardens.

Mistake 10 — Not Checking the Finished Work Properly

What happens: Defects that would have been easily fixed during installation are only discovered after everything is grouted and sealed — or by the client on handover.

The fix: Depends on the defect. Some can be repaired; others require partial or complete re-tiling.

Prevention: Conduct systematic quality checks throughout the job: tap-test every few tiles for hollow sound, check level every few rows, check grout joint consistency, check for lippage. Do a final inspection before grouting — it's the last opportunity to fix anything without major rework.

Learn to Get It Right First Time

Understanding common failure modes and how to prevent them is core to the CPC31320 Certificate III in Wall and Floor Tiling at Wyatt Education Group. Our training covers quality assurance, defect identification, and corrective techniques — giving you the professional standard of knowledge that prevents these costly mistakes on the job.