Polished concrete specification: Section 03 35 43 guide spec

This is a complete CSI 3-part guide specification for polished concrete finishing under MasterFormat Section 03 35 43. Architects, engineers, and general contractors can copy it into a project manual as written or edit the bracketed values to fit the project. It reflects the Bel Covo Slab Boss methodology: the slab assessment dictates the plan, each refinement step states its objectives and hazards, and every pass gets verified before the next. It specifies results, not brands or machines.

How to use this guide specification

Three editing rules keep the section coherent:

1. Edit the bracketed values, not the article structure. Gloss level, aggregate exposure class, flatness tolerance, mockup size, and the workmanship warranty term for the polishing scope are project decisions. The article sequence is the process.
2. Coordinate the related sections. A polished floor is only as good as the slab under it. If the pour is in your scope, coordinate Section 03 30 00 (Cast-in-Place Concrete) for cement content, flatness, and curing method. A cure-and-seal compound applied at the pour will fight the polish later.
3. Keep Part 3 assessment and verification intact. The slab assessment with its deviation-from-grade decision process, plus per-pass scratch-pattern verification, is the difference between a polished floor and a ground floor with topical shine. Every other article assumes both stay.

Section 03 35 43: polished concrete finishing

Part 1: general requirements

1.1 Summary

Work of this section includes mechanical polishing of horizontal concrete surfaces: pre-grind slab assessment, corrective grinding, honing and polishing via progressive metal-bond and resin-bond diamond abrasive tooling, chemical densification, optional grout coating, optional coloring, and optional stain repellent. Section includes field surfaces and edge work performed in parallel.

This section carries three scheduled variants under one set of articles:

Schedule the variant per room or area. Do not write a separate section for a sealed or colored floor produced by the same crew, the same densifier, and the same verification protocol.

1.2 Related sections

• Section 03 30 00, Cast-in-Place Concrete: mix design, placement, flatness, and curing of slabs to receive polishing.
• Section 03 01 30, Maintenance of Cast-in-Place Concrete: resurfacing of existing slabs.
• Section 07 26 00, Vapor Retarders: under-slab moisture protection.
• Section 09 67 23, Resinous Flooring: fluid-applied resinous systems where a coating is specified instead of a polish.
• Section 03 35 19, Colored Concrete Finishing: coloring of concrete that is not mechanically polished.

1.3 References

• ACI 302.1R, Guide to Concrete Floor and Slab Construction.
• ACI 310.1, Specification for Polished Concrete Slab Finishes.
• ASTM E1155, Standard Test Method for Determining FF Floor Flatness and FL Floor Levelness Numbers.
• ASTM D523, Standard Test Method for Specular Gloss.
• ASTM D4039, Standard Test Method for Reflection Haze of High-Gloss Surfaces.
• ASTM D5767, Standard Test Method for Instrumental Measurement of Distinctness-of-Image Gloss.
• CSDA ST-115, Measuring Concrete Micro Surface Texture.
• Concrete Polishing Council (CPC) Polished Concrete Appearance Chart, and CPC Position Statement No. 1, Concrete Polishing Aesthetics.

1.4 Definitions

• Aggregate exposure class: A (cream, no aggregate exposed), B (fine, salt-and-pepper), C (medium aggregate), D (large aggregate). Class is set by grinding depth at the initial cut.
• Gloss level: the finished appearance level per the CPC Polished Concrete Appearance Chart. 1 Flat (ground), 2 Satin (honed), 3 Polished, 4 Highly Polished. Levels are defined by distinctness of image, not by a gloss unit reading. Article 3.6 carries the acceptance values.
• Densifier: a reactive silicate solution that converts calcium hydroxide in the paste to calcium silicate hydrate, hardening the wear surface and the upper layer of the slab to the maximum penetration depth of the densifier.
• Surface roughness (Ra): the average micro-texture of the refined surface, measured in micro-inches or micrometers per CSDA ST-115.
• Distinctness of image (DOI): the sharpness of images reflected in the polished surface, also called image clarity. Measured by image clarity meter per ASTM D5767 on a 0 to 100 scale, where 100 is perfect clarity.
• Haze index: the cloudiness or milky appearance of images reflected in the polished surface. Measured by gloss meter per ASTM D4039 as the numeric difference between specular gloss at 60 degrees and specular gloss at 20 degrees. Haze rises when the surface scatters light, which is why it catches an under-refined pass or residual densifier that a single gloss reading misses.
• Deviation from grade (DfG): any change in floor grade that exceeds a 4 percent slope between two adjacent grade points. Article 3.2 governs identification and remediation.

1.5 Submittals

• Product data: densifier, grout coating material, dye, and stain repellent.
• Tooling and chemistry plan prepared after the slab assessment in Article 3.1. The plan demonstrates a process capable of the specified result; it does not bind the contractor to a particular machine, brand, grit sequence, or pass count.
• Mockup: [10] square feet minimum on the project slab, demonstrating the specified exposure class, gloss level, and any scheduled color.
• Verification log format: the per-pass inspection record to be maintained under Article 3.6.
• Field test reports per Article 3.6: haze index and surface roughness readings, plus distinctness of image readings where DOI verification is scheduled.

1.6 Quality assurance

• Installer qualifications: minimum [5] years of commercial concrete polishing and a documented per-pass verification protocol.
• Mockup: construct at a location directed by the Architect or Owner, using the sequence, tooling, machinery, and chemical treatments intended for the full floor area. Do not proceed with full floor processing until the Architect or Owner approves the mockup in writing. Where instrument verification is scheduled, verify the mockup with the meters specified in Article 2.8.
• The approved mockup is the standard of comparison for the remaining work. Protect the mockup until Substantial Completion.

1.7 Project conditions

• Building enclosed, slab protected from precipitation, and other trades off the work area during polishing.
• Slab cured a minimum of [10] days before the initial cut, depending on ambient conditions during the cure.
• Permanent or temporary lighting adequate for inspection.

1.8 Warranty on the installed work

• Workmanship warranty for the polishing work: [3] years from Substantial Completion. Any longer workmanship term, including a lifetime term that runs for as long as the original purchaser owns the property, is stated on the accepted proposal for the project.

Part 2: products

2.1 Basis of design

This specification serves as a fundamental framework of processes demonstrated to produce desired and measurable results for the Slab Boss polished concrete floor by Bel Covo. It specifies the result and the objectives of each process step rather than a brand, a machine, or a grit sequence. Equivalent systems and methods that meet the requirements of this section may be submitted for approval.

2.2 Equipment and diamond tooling

• Grinding machinery: multi-head planetary or counter-rotating floor grinders, plus hand-held angle grinders and variable-speed hand polishers for edges and spaces inaccessible to larger machines.
• Diamond tooling: progressive grit sequences of diamond abrasives engineered for grinding, honing, and polishing of a structural slab. Tooling selection follows the slab assessment: a metal-bond first cut is not required where a hybrid or resin-bond tool better suits the specified exposure class.

2.3 Densifier

Lithium silicate or tri-solution blend (lithium, sodium, and potassium silicates) densifier formulated to react with free lime in the concrete matrix, selected for penetration depth and minimal residue. Sodium and potassium densifiers that whiten or streak the surface as they dry are not acceptable.

2.4 Grout coating (where specified)

Resinous grout coating applied after the initial cut and scratch-removal pass to fill pits, pores, and small voids, producing a tighter, more uniform field under overhead light. The cured material must withstand the subsequent honing and polishing steps and remain stable for the intended use of the floor.

2.5 Stain repellent (where specified)

Penetrating, non-film, breathable clear treatment compatible with the densifier, formulated to provide stain resistance and enhance the final clarity of the surface without creating a heavy topical film. Burnished into the finished surface per manufacturer instructions.

2.6 Coloring (polished and dyed variant)

Where the schedule calls for a colored polished floor, provide a solvent-borne penetrating dye for interior floors. Dye produces the widest color range with maximum saturation and the most uniform result. It is not completely UV stable; do not schedule it for areas with sustained direct sunlight.

Color selection is confirmed against the mockup on the project slab, not against a printed chart or a sample poured elsewhere. The parent slab is part of the finished color.

2.7 Sealer (sealed concrete variant)

Where the schedule calls for the sealed variant, provide a penetrating sealer or wear coat compatible with the densifier. Film-forming sealers that produce a topical gloss are not a substitute for the mechanical sheen achieved by progressive-grit diamond abrasive polishing and are not acceptable where a gloss level is specified.

2.8 Performance meters

Required for the field verification in Article 3.6:

• Gloss meter: portable dual-angle instrument reading specular gloss at both 20 and 60 degrees, calibrated and used per ASTM D4039, reporting the haze index as the difference between the two readings.
• Surface profilometer (Ra meter): portable, calibrated instrument conforming to ANSI/ASME B46.1, tracking surface micro-texture in micro-inches or micrometers per CSDA ST-115 protocols.

Required only where DOI verification is scheduled:

• Image clarity meter (DOI meter): portable instrument calibrated and used per ASTM D5767.

A dual-angle gloss meter and a profilometer are the instruments this section requires. The image clarity meter costs several times more, so DOI verification is scheduled per project rather than imposed on every floor. Where DOI is not scheduled, the haze index and the surface roughness readings are the numeric acceptance criteria, and the per-pass visual verification still governs the progression.

Part 3: execution

3.1 Examination and slab assessment

Before tooling selection, perform and document a slab assessment: surface hardness, flatness by straightedge or ASTM E1155 survey [FF 35 minimum for polished work], and moisture condition. The assessment produces the tooling and chemistry plan submitted under Article 1.5.

Identify slab defects that could prohibit the desired result in the final polish. For each finding: identify it, report it to the Architect or Owner, and present remediation options with the aesthetic, structural, and performance impacts of each option. Do not proceed with mechanical refinement until remediation selections are made and approved.

• Flatness or levelness out of suitable range produces deviations from grade; Article 3.2 governs.
• Shrinkage cracks, stress fractures, and cold joints may require backfill.
• Lippage, exposed reinforcement, or embedded conduit may require cutoffs, coring, or extensive planing.
• Delaminations and incompetent or uncured cement matrix may require tear-out and patch repairs.

Report slabs that cannot achieve the specified exposure class or gloss level before grinding begins.

3.2 Deviations from grade

Negative deviations (low spots) exceeding a 4 percent slope between two adjacent grade points are not accessible with standard tooling and equipment. Remediation of these spots is not part of the standard polishing service; it is selected and priced during the slab assessment. Where no remediation is selected, these spots remain visible in the finished floor: expect a noticeable difference in aggregate exposure, color, and sheen.

Present these remediation options for each identified deviation:

1. Grind to depth. Grind until the deviation tapers out over a wide area. The deeper cut changes the aggregate exposure around the spot; a light salt-and-pepper field can become full-size aggregate there.
2. Tear-out and patch. Saw-cut, excavate, and pour back. The patch sits dead flush to grade but will not exactly match the adjacent concrete in color or texture, and it adds time and cost.
3. Hand tool. Work the low spot with flexible diamond pads through each step of the sequence. This preserves the surrounding aggregate exposure; labor cost scales with the number of spots.
4. Leave as is. No cost. The spot stays visible in the finished floor.

Selection guidance: where aggregate appearance governs, hand tooling is usually the best option. Where flatness governs, tear-out and patch. Where uniformity of exposure matters less than removing the dip, grind to depth.

3.3 Preparation

Remove existing coatings, adhesives, and contamination identified in the assessment. Repair joints and cracks per the approved repair method. Protect adjacent finished surfaces and vertical elements.

3.4 Mechanical refinement sequence

Each step below states its objectives, its hazards, and the key best practices and methods that matter to the end result. The step must accomplish its objectives; machine type, tooling brand, wet or dry method, and pass count are the contractor’s choice, verified by results.

A. Prep grinding (cut) / aggressive flatness pass

Objectives:

• Remove high spots and curing compounds, achieve the targeted aggregate exposure profile, and provide sufficient flatness for subsequent diamond tooling to make adequate contact with the floor surface, so the scratch pattern of each grit size can be refined through final polish.
• Blend the edge cut with the field cut until there is no visible transition between the two.

Hazards:

• Avoid overly aggressive tooling selections, to mitigate aggregate exposure larger than the desired result.

Key best practices and methods:

• Make edge cuts first using hand-held grinders to establish the desired depth of cut. Keep the cut close enough to the wall for base trim to cover any unpolished floor area.
• Follow edge grinding with planetary machines running parallel to and overlapping the edge cut around the room perimeter, blending the field cut into the edge cut before proceeding with the remainder of the area. This helps ensure a disappearing edge.
• Make multiple passes in opposing directions with large planetary or counter-rotating grinders rather than reaching the desired exposure depth in a single pass.
• Crab the machine left and right as it progresses down a line to blend cut lines and minimize noticeable variations in cut.
• Overlap adjacent cut lines 25 to 75 percent to maximize consistency of cut.
• Sweep or scrub thoroughly and perform a thorough inspection before proceeding to the next step.

B. Scratch removal pass

Objectives:

• Remove deep scratches from the initial cut, particularly where the first cut ran metal-bond tooling, so the field carries a consistent scratch pattern of only the diamond size for this pass.

Hazards:

• Avoid overly aggressive tooling, as above.

Key best practices and methods:

• Inspect the full field for remaining deep scratches before advancing. A scratch left behind at this step survives every later pass.
• Sweep or scrub thoroughly before the next step.

C. Grout coat / pit fill (where specified)

Objectives:

• Pre-densify the surface thoroughly to minimize absorption of grout resin into the cement matrix, which can substantially darken the final color.
• Fill small pits, pores, and microcracks with resinous material competent enough to withstand the subsequent honing and polishing steps and remain stable for the intended use of the floor.

Hazards:

• Avoid mixing large batches of material, particularly in temperatures above 75 degrees F, to control the viscosity of the product and prevent inconsistency of absorption and fill.
• Remove mixed material from service before it reaches its exothermic reaction. Material applied hot pulls out and fills incompletely.

Key best practices and methods:

• Apply the pre-grout densifier to refusal after the initial cut and scratch-removal pass, and let it dry fully before grouting.
• Mix small batches and spread each batch immediately after mixing.

D. Grout cutback

Objectives:

• Remove all residual grout material from the surface, leaving behind only what has filled pits and voids.

Hazards:

• Avoid excessive grinding or overly aggressive diamond tooling during cutback, to prevent cutting past the grouted layer or exposing additional pits.

Key best practices and methods:

• Take light passes and inspect frequently. Stop at the grouted plane.

E. Honing

Objectives:

• Remove all scratches from the grout cutback and pre-hone passes, securing a fully refined [400]-grit surface.

Hazards:

• Avoid hasty inspections and inspections under poor lighting. An incomplete pass discovered late costs every pass in between.

Key best practices and methods:

• After edge honing is complete, make an additional perimeter pass with the planetary machine to ensure the edge-to-field blend.
• Use low-angle lighting or other means to verify the previous pass’s scratch pattern is fully removed and refinement is thorough.

F. Pre-polish densification

Objectives:

• Provide additional densification of the slab matrix to close microscopic pores for long-term durability and abrasion resistance, and to provide the maximum density needed for final polish clarity.

Hazards:

• A properly grouted floor reaches refusal quickly; avoid over-application. Avoid ambient conditions that make the densifier dry too quickly or too slowly.
• Never leave puddles to dry.

Key best practices and methods:

• Clean the floor thoroughly of dust, slurry, and debris before application.
• Spread the densifier evenly and consistently at manufacturer coverage rates, and let it fully penetrate and dry before polishing begins.

G. Polishing

Objectives:

• Remove dried residual densifier from the surface and remove the previous honing scratch pattern while fully refining each next grit size. On a properly placed slab that has been grouted, honed, and densified using best practices, an [800]-grit diamond tool run to full refinement produces a level 4 finish with excellent clarity. Clarity is the goal.

Hazards:

• Avoid excessive rotation speeds and head weight, to keep tooling heat to a minimum and remove all residual densifier from the surface. Cooked residual densifier is often the culprit in areas that lack clarity or read hazy.
• Avoid standing water and spillage. Densifier crystallization is a curing process that continues for weeks; during the first green days, water exposure can re-emulsify the curing densifier and leave etched marks that must be remediated.

Key best practices and methods:

• Progress sequentially through the resin-bond grits, running each grit to full refinement before the next. Pace and pass count are the contractor’s choice; full refinement at each grit is not.

H. Stain repellent application and burnishing (where specified)

Objectives:

• Provide protection against stains and discoloration from spills.
• Enhance durability and cleanability.

Hazards:

• Avoid over-application, which can require excessive cleaning before occupancy.
• Protect adjacent finished surfaces from contamination.

Key best practices and methods:

• Vacuum and microfiber-mop all residue from the polished surface before application.
• Apply ultra-thin coats, microfibering out pools and streaks. Allow full dry per manufacturer instructions.
• Burnish with a high-speed propane or electric burnisher fitted with diamond-impregnated pads [minimum 1500 RPM] to melt and blend the repellent into the refined slab.

3.5 Scheduled variants

• Polished and dyed. Apply dye per Article 2.6 after the surface is opened and densified, and before the final resin passes, so the color sits within the surface rather than on it. Match the approved mockup.
• Sealed concrete. Terminate after the initial cut and densification, omit the honing and polishing steps, and apply the sealer or wear coat per Article 2.7. Aggregate exposure and surface hardness still follow the assessment plan; only the gloss progression is omitted.

3.6 Field quality control

After every pass, inspect the full field under adequate lighting. The scratch pattern of each pass must fully refine the pattern of the previous pass before the next pass begins. Where the pattern shows an incomplete previous pass, return to that pass. Record each inspection in the verification log.

Verify the finished floor against the scheduled gloss level. Acceptance values follow the CPC Polished Concrete Appearance Chart:

The haze index applies at every level and is always required. The distinctness of image column applies where DOI verification is scheduled under Article 2.8. Level 4 may require grout coating to reach the band.

Where the scheduled gloss level is 3 or 4, also verify surface roughness: [20] micro-inches (0.50 micrometers) maximum for level 3, [10] micro-inches (0.25 micrometers) maximum for level 4. Measure Ra directly on the unsealed, honed surface.

Test frequency: a minimum of three tests distributed across the polished surface for areas up to 1,000 square feet, plus one additional test for each additional 1,000 square feet or fraction thereof. This applies to haze index, surface roughness, and distinctness of image alike. Evaluate compliance against the mean of the readings. Record readings in a log indexed by building grid line and submit the log to the Owner’s representative weekly.

A topical film applied over an under-refined surface can raise a single gloss reading while the floor still scatters light. The haze index catches that condition, and Article 2.7 bars film-forming sealers as a substitute for mechanical refinement wherever a gloss level is specified.

The sealed variant carries no gloss level requirement; verify instead that densifier coverage is uniform and that the sealer has not produced a topical film.

3.7 Protection

Protect finished surfaces from other trades until Substantial Completion. Prohibit acids, harsh cleaners, and taped coverings that leave adhesive residue.

What about dyed or sealed floors?

Two finishes that look like separate scopes are scheduled variants of this one section, because the same crew runs the same assessment, the same densifier chemistry, and the same verification protocol on both:

• Polished and dyed adds the coloring articles. MasterFormat nests it as 03 35 43.13, so it belongs inside this section rather than beside it. Dye goes into the open surface during the progression, never as a film over a finished floor.
• Sealed concrete terminates after the initial cut and densification, omits the honing and polishing steps, and takes a penetrating sealer or wear coat. It is the lowest-cost finished-floor option and it carries no gloss requirement.

Schedule the variant per room or area. The exception is coloring on a floor that is not polished at all: that specifies under Section 03 35 19, Colored Concrete Finishing.

Specifying the upgrade options

The three named options in the Slab Boss system translate to spec language as follows:

A base specification (exposure class A or B, gloss level 2, single densification) is a complete polished floor. The options are how a project buys a tighter field, a deeper cut, and a higher gloss ceiling.

When the pour is in your scope

The single highest-leverage decision for a polished floor happens before the truck arrives. If your project includes the slab pour, specify the concrete for the finish: higher cement content, FF 35 or better, and a curing method that does not leave a compound the polish has to fight. Our Pour-4-Polish specification approach documents that pour-side discipline, and the general contractor page explains how we run both scopes under one subcontract.

From the field

Polished concrete floors we finished

Related documents

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