Polished concrete floors over tiles offer a smart way to refresh your space without the cost and mess of complete removal. At Wirth Floor, we’ve guided countless property owners and builders across Brisbane, the Gold Coast, and the Sunshine Coast through this transformation.

The process requires precision at every stage, from assessing your existing tiles to applying the overlay system correctly. Get this right, and you’ll have a durable, modern floor that lasts for years.

Assessing and Preparing Your Tile Foundation

Test Your Tiles for Hidden Problems

Before any concrete overlay goes down, your existing tiles need a thorough evaluation. Most tiled floors hide problems beneath the surface-hollow spots where adhesive has failed, hairline cracks, or moisture trapped underneath. A coin or marble test reveals these issues immediately. Tap systematically across the room and listen for a hollow sound, which signals poor bonding between tile and substrate. If you find hollow areas larger than a few tiles, this becomes a serious problem. A poorly bonded tile will shift under foot traffic and cause your new overlay to crack within months.

Address Surface Texture and Grout Issues

Glazed or textured tiles present another challenge because their smooth surface resists bonding. Sand these tiles back to roughen the surface before any concrete goes on top. Wide grout joints also cause visible outlines and settling in the new layer, so seal them before installation prevents this aesthetic problem. If cracks run through tiles, assess whether they indicate structural movement in the slab below. Movement in the substrate means your overlay will crack too, no matter how well you prepare the surface.

Clean and Degrease Thoroughly

Once you’ve confirmed the tiles are sound and firmly fixed, cleaning and degreasing becomes non-negotiable. Grease, dirt, and old sealants block adhesion between tile and overlay. A degreaser followed by thorough rinsing removes these barriers, but residual moisture is equally problematic. Allow the surface to dry completely before moving forward-typically 24 hours in dry conditions.

Any damaged tiles should be removed and the gaps filled with concrete patch material to create a level base.

Prime and Placed for Height Changes

Apply several coats of primer to prepare the tile surface for concrete bonding and improve adhesion significantly. This step takes time but directly affects whether your overlay stays put or delaminates within a year. Floor height will increase by several inches after the overlay, so check door thresholds, stair alignments, and cabinet clearance before you start. Planning these transitions now prevents costly adjustments later. With your foundation properly assessed and prepared, you’re ready to move into the actual installation process.

Applying and Finishing Your Overlay

Mix and Apply the Overlay System

Once your tile surface is properly primed and prepared, the concrete overlay installation begins. The overlay itself is hand-mixed on site, then applied directly over your primed tiles in a layer between 2 and 3 millimetres thick. This thin application keeps your floor height manageable and preserves door clearances and transitions. The overlay material combines stone and liquid polymer, creating a bond that hardens significantly stronger than the tile adhesive underneath. Installation speed matters here: the overlay must be applied and initially set within a specific window, usually completed in about a day. This means minimal disruption compared to full tile removal, which often stretches across multiple days and creates far more dust and debris.

Wait for Full Curing Before Grinding

Grinding and polishing happen only after the overlay has fully cured, typically around 7 to 10 days depending on temperature and humidity. Rushing this step causes the surface to chip or crack under the grinding equipment, ruining weeks of preparation work. Temperature and humidity directly affect curing speed, so monitor site conditions during this waiting period. Once the overlay hardens completely, your floor transforms from a flat grey surface into the polished finish you want.

Grind and Polish to Your Desired Finish

Professional-grade equipment with vacuum systems captures over 95 per cent of dust during grinding, protecting your home and reducing cleanup time significantly. The grinding process starts with coarser abrasives and progresses to finer grits, each pass revealing more stone aggregate and building toward your desired gloss level. You can choose from high-gloss finishes that reflect light dramatically, or more subtle honed finishes that reduce glare in bright spaces. Colour staining and decorative aggregates integrate during this phase to match your interior design.

The final grinding pass determines your gloss level, so communicate your preference clearly with your installer before work starts.

Seal the Surface for Long-Term Protection

The final step is sealing, which protects your new surface from moisture and staining. For mechanically polished concrete solutions you generally only have to reapply the protective sealer every 10 years. This seal is not optional-without it, concrete’s porous nature means moisture will penetrate and stains will set permanently. Use only pH-neutral cleaners during maintenance and avoid ammonia, bleach, or vinegar, which damage the finish and cause discolouration. Microfibre mops protect the polish better than traditional cotton mops, reducing abrasion and keeping your floor looking sharp longer.

Planned Your Maintenance Strategy

Spills require prompt attention to prevent staining, and daily sweeping removes grit that can scratch the surface under foot traffic. Your sealed floor resists most stains effectively, but the quality of your maintenance directly affects how long that seal lasts. High-traffic commercial spaces demand more frequent resealing and stricter cleaning protocols than residential kitchens. Understanding these maintenance demands now helps you decide whether this finish suits your space’s actual use patterns, which brings us to the common mistakes that derail even well-prepared installations.

Common Mistakes That Ruin Tile Overlay Projects

Surface preparation errors top the list of failures we observe on job sites across Brisbane, the Gold Coast, and the Sunshine Coast. Your tiles might appear clean to the naked eye, but leftover adhesive, old sealant residue, and grease create a slippery foundation that prevents proper bonding. Overlays fail within six months when installers skip the degreasing step or fail to allow adequate drying time. The tile surface must be mechanically roughened if glazed, primed with multiple coats, and allowed to cure fully before any overlay touches it. Hollow tiles discovered during the coin test represent serious structural problems, not minor issues to overlook. If bonding has already failed between tile and substrate, that failure spreads to your new overlay like a structural infection. Removing and replacing those hollow sections takes time, but skipping this work guarantees cracks in your finished floor.

Selecting the Wrong Overlay Product

Not all concrete overlays perform equally across different conditions. Water-based cementitious systems work well over sound tiles, while others require different substrate conditions entirely. Thin micro-toppings under one-eighth inch thick suit some applications but fail in high-traffic kitchens or commercial spaces where durability matters. A professional assessment evaluates your actual floor condition, desired finish, budget, and realistic timeline before any product selection occurs. Cost-based decisions without understanding your substrate’s movement patterns or the traffic load your space will endure create expensive problems later. The overlay you choose must match both your site conditions and your space’s actual use patterns.

Rushing the Curing Phase

Concrete overlay systems need seven to ten days to fully cure depending on temperature and humidity, yet many projects advance to grinding after just three or four days. Grinding before full cure causes surface chipping, crazing, and failure that requires complete removal and reapplication. This represents a major setback-a failed overlay means tearing out material that cost thousands and took days to install, then starting over. Temperature below 15 degrees Celsius or humidity above 85 per cent extends curing times significantly, and site conditions during winter or wet seasons demand patience and monitoring. Installers who ignore weather conditions and push forward on schedule create floors that fail within months. The difference between a thirty-year floor and a three-year floor often comes down to respecting curing requirements without compromise.

Ignoring Substrate Movement and Structural Issues

Movement in the underlying slab causes your overlay to crack regardless of surface preparation quality. An anti-fracture membrane placed between overlay and substrate in high-risk areas prevents cracks from spreading upward through your new finish. Cracks running through tiles indicate potential structural movement in the slab below, which demands investigation before overlay installation proceeds. A well-laid slab has an expected lifespan of up to 40 years, but only if the foundation remains stable. If the underlying slab shifts or settles, the top layer fails sooner, no matter how well you prepared the surface. Addressing substrate stability before installation protects your investment far more effectively than hoping the overlay will bridge the problem.

Overlooking Height Changes and Transitions

Floor height increases by several inches after the overlay application, which affects door thresholds, stair alignments, and cabinet clearance throughout your space. Failing to plan these transitions before installation creates costly adjustments after the work is complete. Moisture can become trapped in areas where floor height changes occur, leading to damage beneath the overlay. Assess all transitions and clearances during the preparation phase, not after the overlay hardens. This planning step takes minimal time but prevents major complications that emerge months after installation.

Final Thoughts

Polished concrete floors over tiles succeed when you respect three core principles: thorough surface preparation, patience during curing, and realistic maintenance expectations. Skip any of these, and your investment fails within months. The preparation phase determines everything that follows, as hollow tiles, glazed surfaces, grease residue, and inadequate priming create bonding failures that no amount of grinding can fix.

Long-term performance depends on maintenance discipline. Your sealed polished concrete floor over tiles resists stains and scratches effectively, but only if you clean with pH-neutral products and address spills promptly. High-traffic areas need resealing every three to five years, while residential spaces may stretch longer between applications. Daily sweeping and microfibre mopping protect the finish far better than harsh chemicals or abrasive tools.

Professional installation matters more than most property owners realise, as the difference between a floor lasting three decades and one failing within three years often comes down to installer experience and attention to detail during curing. Contact Wirth Floor for a professional assessment of your existing tiles and a realistic timeline for your project across Brisbane, the Gold Coast, and the Sunshine Coast.