Modern polished concrete floors have become the go-to choice for property owners and builders across Brisbane, the Gold Coast, and the Sunshine Coast. They’re durable, low-maintenance, and deliver a sleek aesthetic that works in residential and commercial spaces alike.

At Wirth Floor, we’ve guided countless projects through the polishing process, and we know the steps that separate a stunning finish from a disappointing one. This guide walks you through everything from assessing your concrete foundation to applying the final protective seal.

Getting Your Concrete Ready for Polishing

Surface preparation accounts for up to 70 per cent of a polished concrete project’s timeline, and this statistic reveals everything about its importance. Most property owners underestimate this phase, but the difference between a polished concrete floor that looks stunning for decades and one that fails within years comes down to how thoroughly you assess and treat the foundation. Your concrete slab needs evaluation for structural soundness, moisture content, and surface condition before any grinding begins.

Testing Your Concrete’s Suitability

A Mohs hardness test confirms your concrete rates at least 5, meaning it’s dense enough to polish effectively. The water drop test reveals porosity-if water beads on the surface, your concrete is suitable; if it absorbs immediately, you’re dealing with a weak top layer that may require significant remediation. Moisture vapour emission testing using the calcium chloride method is non-negotiable; if levels exceed 3 pounds per 1,000 square feet in 24 hours, you’ll need to install a moisture barrier (typically an epoxy system) before polishing can proceed safely.

Addressing Cracks, Spalling, and Uneven Surfaces

Cracks under a quarter inch respond well to concrete patching compound, but larger cracks demand epoxy injection to restore structural integrity and prevent widening later. Spalling-where the surface flakes or breaks away-and uneven areas require a resurfacer applied to holes and damaged spots, ensuring the floor sits at a consistent level before grinding starts. This preparation step prevents complications during polishing and extends the floor’s lifespan significantly.

Removing Old Coatings and Contaminants

Existing coatings, adhesives from old flooring, and contaminants present your biggest obstacles. Remove old tile or hardwood using floor scrapers or chisels, then tackle adhesive residue with grinders or chemical strippers; this work is tedious but absolutely necessary because leftover adhesive prevents proper grinding and polishing. Oil stains, grease, and dirt require a degreaser followed by pressure washing to expose the true concrete surface.

Dealing with Laitance on New Slabs

If you’re working on a newly poured slab, the top 5 to 7 millimetres may contain laitance-a weak, powdery layer that’s difficult to detect without specialised testing equipment like a Schmidt Hammer. Removing laitance requires the correct grinding equipment and can be time-intensive; in some cases, removing that much material isn’t practical, so extra resin may be needed to reach a sound substrate. Once your concrete passes these assessments and you’ve completed all repairs and cleaning, you’re ready to move into the grinding and polishing phase, where the actual transformation begins.

Grinding and Polishing Your Concrete

Starting with Coarse Grinding

Once your concrete foundation passes inspection and all repairs are complete, the grinding and polishing phase transforms your prepared slab into a mirror-like surface. This process uses diamond-embedded tools in a carefully controlled progression to expose the aggregate beneath the surface and create the shine property owners expect. Start with coarse grinding to remove any remaining adhesive residue, old coatings, and the weak laitance layer you identified during preparation. This initial grinding exposes fresh concrete and the decorative aggregate; most sites complete this stage in one to two days depending on floor size and slab condition.

A planetary grinder ensures even coverage across the entire space and prevents the directional swirl marks that single-disc machines often create. The work demands precision because rushing or skipping steps results in visible swirl marks, dull patches, or uneven reflectivity that no amount of sealing can fix later.

Progressive Grinding to Smooth the Surface

After coarse grinding, move to 120 and 220 grit pads to smooth the surface and eliminate the scratches left by heavier grinding. This progression is non-negotiable because jumping from coarse grinding directly to fine polishing leaves visible gouges that become permanent flaws in your finished floor. Most contractors complete this intermediate stage over one to two days, depending on project scope.

Apply a concrete densifier after reaching 220 grit and allow 24 hours for it to cure. This chemical treatment closes the pores in your concrete and creates a harder, more durable surface that reflects light more effectively. The densifier bonds cement particles together, which is why skipping this step results in a dull, porous finish no matter how fine your final grit progression goes.

Fine Polishing to Achieve Your Desired Finish

The final polishing phase uses grits from 400 up to 3000 depending on the look you want. An 800 grit finish delivers a satin appearance suitable for commercial kitchens or spaces where slip resistance matters, while 3000 grit produces the high-gloss mirror finish that defines modern polished concrete. This stage typically takes two to three days on larger commercial projects.

After completing your final grit progression, vacuum all dust thoroughly and wipe the surface with a dry cloth to remove any remaining particles. This preparation step is essential before sealing begins.

Sealing and Protecting Your Polished Floor

Sealing comes next and is absolutely essential to lock in your shine and protect the floor from water, grease, oil, and everyday wear. Apply a breathable sealer in multiple coats; breathable formulas prevent moisture from becoming trapped beneath the seal, which causes adhesion failure and costly repairs down the track.

Use an applicator spray to achieve uniform coverage without streaks or thin spots. Allow at least 45 minutes between coats, and the sealer dries in approximately 30 minutes. Avoid heavy foot traffic for the first 28 days to allow the densifier and sealer to fully cure and bond with the concrete. During this curing period, use only pH-neutral cleaners for any necessary maintenance; acidic or alkaline products dull the finish and compromise the protective seal you’ve worked to establish.

With your polished concrete floor now complete and cured, the next phase focuses on the design options and customisation techniques that transform a functional surface into a statement piece that reflects your property’s unique character and style.

Customising Your Polished Concrete Finish

Your polished concrete floor doesn’t have to be plain grey. The real opportunity lies in exposing different aggregates, adding colour, and incorporating patterns that transform your floor into a design statement. What you see in the final finish depends entirely on how deep you grind and which techniques you apply during the polishing process.

Exposing Aggregate for Visual Interest

Aggregate exposure starts during the coarse grinding phase, where you remove the top cement-rich layer to reveal the stones beneath. If your concrete contains decorative aggregates like granite chips, river rocks, or coloured stones, grinding to 120 grit exposes them subtly, while pushing to 220 or 400 grit reveals them dramatically. The deeper you grind, the more aggregate shows, and the more visually interesting your floor becomes.

Most property owners on the Gold Coast and Sunshine Coast try 220 grit as the sweet spot because it exposes enough aggregate for visual interest without requiring excessive grinding time. If your existing concrete has no decorative aggregates, you face two choices: accept the monochrome look or consider a stain or dye to add colour and depth.

Adding Colour with Stains and Dyes

Concrete stains chemically react with the cement, creating permanent colour that won’t peel or fade like surface coatings. Acid-based stains produce earthy tones and mottled effects that mimic natural stone, while water-based stains offer more consistent, controllable colour in broader ranges. You apply stain after your final polishing grit but before sealing; the open pores from polishing absorb the stain evenly, creating the depth you want.

Expect to spend between 500 and 2,000 dollars on staining a medium residential floor, depending on stain type and the complexity of your design. Many Brisbane builders combine staining with scoring or saw-cutting to create geometric patterns that break up large expanses and add visual direction.

Creating Patterns with Scored Lines

Scored lines serve a practical purpose too: they control cracking in concrete slabs. You cut score lines before final sealing, typically using a concrete saw with a diamond blade to a depth of about 6 millimetres. The contrast between polished sections and scored grooves creates shadow lines that emphasise your design intent.

Simple geometric grids or parallel lines typically age better and look cleaner than intricate designs that accumulate dust in their grooves. Scored patterns transform warehouse spaces and retail areas, making them feel intentional and designed rather than purely functional.

Final Thoughts

Installing modern polished concrete floors demands attention at every stage, from the initial moisture and hardness testing through to the final sealing application. The most common failures we see stem from rushing surface preparation or skipping the densifier step, both of which compromise durability and appearance. Your concrete foundation determines everything that follows, so invest time in assessment and repair before grinding begins.

Once polishing is complete, the 28-day curing period isn’t optional; heavy foot traffic during this window prevents the densifier and sealer from bonding properly, leaving you with a floor that fails prematurely. Daily dust mopping removes grit that scratches the surface, while weekly damp mopping with pH-neutral cleaner preserves the shine without dulling it. In high-traffic areas like retail spaces or commercial kitchens, reapply sealer every 12 to 18 months to maintain protection and reflectivity.

Modern polished concrete floors deliver durability that outlasts most flooring options, with proper installation and maintenance supporting a 20 to 30-year lifespan. The low maintenance requirements mean lower long-term costs compared to timber, tile, or removable coverings. Contact Wirth Floor to discuss your project and ensure your installation meets the highest standards from start to finish.