Corrected for practical accuracy and Queensland safety requirements on 20 July 2026.

Installing a polished concrete floor is not a universal sequence of grit numbers, cure times and products. The achievable finish depends on the slab, how it was placed and finished, its age and condition, the intended aggregate exposure, edges and joints, the building programme and the way the completed space will be used.

This guide explains the decisions a client, designer, builder and flooring contractor should resolve before work starts. It does not replace a site assessment, a project specification or the selected product manufacturers' current instructions.

1. Define the finish before pricing the work

Begin with the visual and functional outcome rather than a generic request for "polished concrete." Confirm whether the project is considering a mechanically polished concrete system, a honed and sealed finish, a topical coating or another concrete treatment. These systems can look similar in photographs while using different processes, protection and maintenance.

Record the proposed sheen, aggregate exposure, colour expectations, edge treatment, transitions, stairs or ramps, skirtings, penetrations and areas hidden by joinery. Natural concrete varies. Aggregate distribution, cracks, patches, trowel marks and previous work can remain visible or become more obvious after grinding, so samples and written appearance tolerances are more useful than a promise of perfect uniformity.

2. Assess the actual slab

An existing slab should be inspected for coatings, adhesives, sealers, curing compounds, contamination, laitance, dusting, cracks, joints, spalls, previous repairs, moisture symptoms, flatness and access limitations. A new slab should be coordinated before placement because the concrete mix, placing, finishing, curing, protection and later building trades can affect the final appearance.

Crack width alone does not diagnose the cause or prove that a crack is inactive. Continuing movement, vertical displacement, water entry or structural concern should be referred to the responsible builder, engineer or other competent professional. Cosmetic filling cannot make an actively moving joint or crack disappear permanently.

Moisture testing should follow the requirements of the proposed complete system and the relevant project professional. One online relative-humidity number is not a universal pass/fail threshold for every slab, instrument, sealer, guard or coating. Record the test method, locations, conditions, readings and acceptance criteria instead.

Use the site's exposure, not a generic Brisbane climate claim

A Brisbane, Gold Coast or Sunshine Coast address does not prove that a floor will experience the same humidity, salt, sunlight, temperature or water as another property in that region. Record whether the area is internal, external, air-conditioned, naturally ventilated, exposed to weather, near a frequently opened coastal frontage, subject to wet cleaning or affected by drainage or groundwater conditions.

Polishing or densifying the top surface does not waterproof a slab, stop reinforcement corrosion, prevent mould elsewhere in a building or make concrete immune to cracks and movement. Those outcomes depend on the slab and building design, exposure, drainage, moisture pathways, detailing and maintenance. Structural deterioration, corrosion signs or water entry should be assessed by the responsible building professional rather than diagnosed from a suburb or a surface reading.

Concrete has thermal mass, but an exposed polished slab does not guarantee an energy saving. The Australian Government-backed Your Home thermal-mass guidance explains that thermal mass can improve or worsen comfort and energy use depending on climate, orientation, insulation, glazing, shading, ventilation and operation. Treat any energy outcome as a building-design question.

3. Coordinate the construction programme

Polished concrete is affected by work before and after the flooring contractor arrives. The project team should agree:

  • when walls, glazing, ceilings, services, joinery and other floor finishes will be installed;
  • which edges and corners the grinding equipment must reach;
  • how the slab will be protected without trapping contamination or marking the surface;
  • site power, water, lighting, ventilation, waste and slurry arrangements;
  • access for equipment and safe separation from occupants and other trades;
  • when the floor can receive foot traffic, wheeled loads, cleaning and fit-out work; and
  • who accepts samples, repairs, appearance variation and the completed floor.

Do not rely on a generic two-day, five-day or seven-day promise. Programme depends on floor area, access, edge work, removal, repairs, chosen system, environmental conditions, product windows, power, trade interfaces and the acceptance process.

4. Plan concrete-grinding and silica controls

Grinding and polishing concrete can generate respirable crystalline silica. Workplace Health and Safety Queensland's silica code information identifies grinding and polishing concrete as processes that can generate respirable crystalline silica. Its specific floor-grinder guidance describes required engineering-control options and associated clean-up controls.

The responsible business must select, use and maintain controls that comply with the current Queensland requirements and suit the task. A household vacuum, open fan or sheet of plastic is not a substitute for the required control system, training, respiratory protection where required, exclusion, housekeeping and exposure-management process. Suspected asbestos-containing flooring, adhesive or other material also needs assessment before disturbance.

5. Establish the first cut and repair approach

The initial grinding approach is selected after test areas reveal how the slab responds. Tooling, bond, machine weight, pass pattern and starting stage vary with concrete hardness, coatings, surface condition and the required exposure. Starting at one nominated grit for every slab can remove too much material, leave unwanted scratches or fail to remove the existing surface.

Repairs should be agreed before they are made. Confirm the treatment of cracks, joints, bolt holes, penetrations, spalls, edge damage and previous patches; the expected colour contrast; and which movement joints must remain functional. Repair materials need to be compatible with the substrate, exposure and later polishing or protective treatment.

6. Refine the surface to the approved result

After the agreed exposure is reached, the floor is refined through a documented sequence suited to the slab and system. Each stage should remove the relevant scratches from the previous stage before the work progresses. Skipping stages or quoting the final grit alone does not prove the completed floor will have the requested appearance or performance.

A densifier may form part of a mechanically polished system, but product selection, coverage, timing, residue removal and compatibility are product-specific. Densifier is not a structural repair, waterproofing treatment or universal stain barrier. Guards, penetrating treatments or topical sealers also have different purposes and maintenance needs; the selected complete system should be recorded rather than described only as "sealed."

7. Specify slip performance for the actual location

Gloss does not by itself define whether a floor is suitable, and no concrete finish is universally non-slip. Contamination, cleaning, footwear, slope, drainage, texture and wear all affect slip risk. Workplace Health and Safety Queensland's floor and ground-surface guidance explains why there is no single correct slip-resistance level for every situation.

For stairs, ramps and related locations, the project team should also identify the applicable National Construction Code pathway and current testing requirements. The ABCB's stairway and ramp provisions are a useful starting point for relevant housing work, but the correct NCC volume, edition, state adoption, building classification and project solution must be confirmed by the responsible building professional.

8. Inspect, protect and hand over the floor

Handover should record the installed system, approved sample or appearance range, repair and joint details, product technical and safety data, cleaning instructions, protection requirements and any test results specified by the project. Review the floor under agreed lighting and access conditions, not only through selected photographs.

Temporary protection must suit the floor and the remaining trades. Tape, trapped moisture, grit, plaster, paint, metal filings, moving equipment and early chemical exposure can mark a new finish. The builder or site manager should control access and document responsibility for later damage.

9. Use a finish-specific maintenance plan

Remove abrasive grit, clean spills promptly and use chemistry and equipment approved for the installed system. Do not assume every polished floor needs resealing on the same annual or three-year timetable. Mechanically polished concrete, a guarded floor and a topical sealer can require different work. Inspect traffic paths, entrances and spill zones, then plan specialist work from actual condition and the product instructions.

For ongoing care, see Wirth Floor's polished concrete maintenance guide.

Information to include with a polished-concrete enquiry

  • site address, building type and whether the slab is new or existing;
  • plans, area, room uses, stairs, ramps, edges and transitions;
  • current surface, coatings, contamination, cracks, repairs and moisture history;
  • preferred exposure and sheen, with reference images used only as direction;
  • traffic, wheeled loads, spills, sunlight, wet conditions and cleaning process;
  • site power, water, access, hours, occupied-area controls and other trades;
  • programme, handover date and required testing or project documentation; and
  • photos of the whole floor and close views of representative defects.

Wirth Floor provides polished concrete and concrete preparation services for suitable projects across Brisbane, the Gold Coast and the Sunshine Coast. Request a project discussion with the plans, photos, floor area, intended use and programme.

This article provides general planning information, not WHS, building, engineering or specification advice. Final methods, materials, controls, tests, responsibilities and acceptance criteria must reflect the site, current law and project documents, manufacturer information and advice from the responsible competent persons.