Polishing an existing concrete floor transforms worn surfaces into durable, attractive flooring that rivals expensive alternatives. This process requires specific equipment, techniques, and patience to achieve professional results.

We at Wirth Floor have guided countless Brisbane property owners through successful concrete polishing projects. The right approach saves money while creating floors that last decades with minimal maintenance.

Assessment and Preparation of Existing Concrete

Start by testing the concrete age with a simple water drop test. Water should absorb slowly, not bead up or disappear instantly. Concrete needs at least 28 days of curing before polishing begins, but older slabs often perform better. Check moisture levels with ASTM F2170 standards – relative humidity must stay below 75 per cent for optimal results. Floors that exceed this threshold require additional drying time or professional moisture mitigation.

Surface Defects That Stop Polishing Progress

Walk the entire floor systematically and mark cracks wider than 1/8 inch with chalk. These need professional repair before grinding starts. Small holes from previous flooring installations require patching compound that matches existing concrete density. Oil stains, paint splatters, and adhesive residue create permanent discolouration that polishing cannot remove. Document these areas with photos – they may need acid etching or overlay solutions instead of traditional polishing. Cold joints between concrete pours often show as visible lines that become more pronounced after polishing (identify these early in your assessment).

Coating Removal Sets Polishing Success

Remove all existing sealers, waxes, and coatings before grinding begins. Test coating thickness with a razor blade – anything thicker than paint film requires mechanical removal. Chemical strippers work for thin coatings but create disposal challenges. Mechanical scarification with diamond grinding removes coatings completely while it prepares the surface texture. Start with 16-30 grit metal bond pads for heavy coating removal. Power wash the floor after coating removal, then allow 24-48 hours drying time.

Workspace Preparation for Equipment Setup

Clear the entire work area of furniture, equipment, and debris before equipment arrives. Seal off adjacent rooms with plastic sheeting to contain dust (even with collection systems). Check electrical requirements for grinding equipment – most professional machines need 220V outlets with adequate amperage. Verify ceiling height clearance for equipment operation and material storage. Plan equipment access routes through doorways and around obstacles to avoid delays once polishing begins.

Equipment and Materials for Concrete Polishing

Professional concrete polishing requires specific machinery that rental stores rarely stock. Planetary grinders with three or four heads distribute weight evenly and prevent gouging that single-disc machines create. These machines typically weigh 200-400 pounds and feature variable speed controls from 150-1500 RPM. The Husqvarna PG 280 and HTC 270 represent industry standards for mid-size residential projects, while larger commercial spaces need walk-behind units with 800-pound weights. Angle grinders or consumer-grade equipment will show obvious swirl marks and uneven surfaces that cannot be corrected.

Diamond Pad Selection Controls Final Results

Metal bond diamonds remove coatings and level surfaces with 16-50 grit ratings for initial cuts. Resin bond pads create the actual polish through systematic progression: 100 grit removes scratches from metal bonds, 200 grit eliminates 100-grit marks, then continue through 400, 800, 1500, and 3000 grit sequences. Each grit level must completely remove scratches from the previous step before you advance. Skip grits and you create permanent haze that requires restart from coarser stages. Quality diamond pads cost 40-60 dollars each and wear out after 2000-4000 square feet (concrete hardness affects lifespan). Wet methods produce superior results but create slurry disposal challenges, while dry methods with dust collection offer faster completion.

Safety Equipment Prevents Serious Health Risks

Concrete dust contains crystalline silica that causes permanent lung damage after repeated exposure. NIOSH-approved P100 respirators provide minimum protection, but powered air-purifying respirators offer superior comfort during long sessions. Safety glasses must seal completely around eyes since concrete particles ricochet unpredictably during operations. Hearing protection becomes mandatory with grinders producing 85-95 decibel noise levels throughout 8-hour workdays.

Steel-toed boots with puncture-resistant soles protect feet from dropped equipment and sharp concrete fragments.

Workspace Setup Affects Equipment Performance

Check electrical requirements before equipment arrives – most professional machines need 220V outlets with adequate amperage. Plan dust collection routes and verify adequate ventilation systems work properly. Position equipment storage areas away from active work zones to prevent accidents. Test all electrical connections under load conditions before you begin the actual process.

Step-by-Step Polishing Process

Start with 16-30 grit metal bond diamonds to remove surface irregularities and expose fresh concrete. Move the grinder in overlapping passes at walking speed and cover each area twice in perpendicular directions. The concrete surface should show consistent scratch patterns without deeper gouges or missed spots. Switch to 80 grit resin bonds to eliminate metal bond scratches completely – any remaining deep marks will show through all subsequent steps. Apply chemical densifier after 80 grit work while concrete pores remain open. Sodium silicate penetrates and chemically hardens the surface matrix for superior polish retention.

Progressive Grit Advancement Creates Mirror Finish

Continue through 200, 400, 800, 1500, and 3000 grit resin bond sequences without skipping steps. Each grit must completely remove scratches from the previous level before you advance – incomplete scratch removal creates permanent haze that requires restart. Wet each section with spray bottles between grit changes to reveal scratches under proper light. The 800 grit stage produces initial gloss while 1500 grit develops reflective properties.

Final 3000 grit work creates mirror-like surfaces that reflect overhead lights clearly. Professional installations require proper equipment and experienced operators.

Surface Preparation Between Grit Changes

Vacuum all dust and debris between each grit progression to prevent contamination. Check the concrete surface under bright work lights to identify missed scratches or uneven areas. Fill any chips or holes with patching compound that matches concrete density (allow 24 hours cure time before you continue). Test small areas with water drops to verify consistent porosity across the entire floor. Temperature affects chemical reactions during densifier application – maintain workspace between 65-75 degrees Fahrenheit for optimal results.

Final Sealer Application Protects Surface Quality

Clean all residue with industrial vacuums followed by tack cloth wiping before sealer application. Apply penetrating silicate sealers with microfibre rollers in thin, even coats that avoid puddles or overlap marks. Most quality sealers require 45-60 minutes between coats with two applications standard for residential projects. Commercial applications need three coats for heavy traffic protection. Temperature and humidity affect cure times significantly – ideal conditions range 65-75 degrees Fahrenheit with relative humidity below 50 per cent.

Final Thoughts

Polishing an existing concrete floor typically takes 3-5 days for residential projects, with commercial spaces needing 1-2 weeks depending on square footage. Each grit progression demands complete drying between steps, and sealer application adds 24-48 hours cure time before foot traffic resumes. Temperature and humidity control affect timeline significantly (maintain 65-75 degrees Fahrenheit with low humidity for best results).

Maintenance stays minimal once the process completes properly. Daily dust mopping removes abrasive particles that dull surfaces over time. Weekly damp mopping with pH-neutral cleaners maintains appearance without damaging the sealer, and you should reapply penetrating sealers every 3-5 years to preserve stain resistance.

Professional installation becomes necessary for floors exceeding 500 square feet or surfaces with extensive damage. Complex repairs, moisture issues, and coating removal often require specialised equipment that rental stores cannot provide. We at Wirth Floor handle polished concrete projects with commercial-grade equipment and proven techniques for lasting results.