Concrete resurfacing specification: Section 03 01 30 guide spec

This is a CSI 3-part guide specification for resurfacing existing concrete: evaluation, crack and spall repair, surface preparation, bonded cementitious overlay, and the decorative or polished finish placed on top. Architects, engineers, and general contractors can copy it into a project manual or edit the bracketed values. It covers the three overlay systems Bel Covo installs, including the polishable overlay that lets a failed slab reach a polished floor without replacement.

How do you use this guide specification?

1. Pick the right section number first. Resurfacing a deteriorated existing slab belongs to Section 03 01 30. A new wear topping over sound new construction belongs to Section 03 53 00, Concrete Topping. The scope in Part 1.1 tells you how to retain these articles by reference in that case.
2. Keep the examination article. Article 3.1 requires a sounding survey, a crack map, and moisture testing before preparation starts. It is the article that decides whether the project should be an overlay at all.
3. Edit the bracketed values. Surface profile range, moisture limits, mockup size, bond-test locations, and repair methods are project decisions.

Section 03 01 30: concrete resurfacing

Part 1: general requirements

1.1 Summary

Work of this section includes resurfacing of existing cast-in-place concrete: evaluation of the existing slab, crack and spall repair, surface preparation, application of a cementitious overlay, and the scheduled decorative or polished finish on the new surface.

Where a wear topping is placed over new construction rather than over a deteriorated existing slab, specify under Section 03 53 00, Concrete Topping, and retain the preparation and finishing articles of this section by reference.

1.2 Related sections

• Section 03 30 00, Cast-in-Place Concrete: new slabs-on-grade where replacement is selected over resurfacing.
• Section 03 35 43, Polished Concrete Finishing: mechanical polishing, including polishing of an overlay placed under this section.
• Section 09 67 23, Resinous Flooring: resinous systems where a coating is selected instead of a cementitious overlay.
• Section 07 92 00, Joint Sealants: sealant work outside the floor plane.

1.3 References

• ICRI Guideline 310.2R, Selecting and Specifying Concrete Surface Preparation (concrete surface profile, CSP).
• ICRI Guideline 310.1R, Surface Preparation for Sealers, Coatings, and Polymer Overlays.
• ACI 546R, Guide to Concrete Repair.
• ASTM C1583, Standard Test Method for Tensile Strength of Concrete Surfaces (pull-off / bond test).
• ASTM F1869 and ASTM F2170 for moisture vapor emission and in-situ relative humidity.

1.4 Definitions

• Overlay: a cementitious layer bonded to a prepared existing slab, placed to restore surface condition or to receive a decorative or polished finish.
• Delamination: separation of the overlay from the substrate, detected by sounding.
• Sounding: survey of the slab by chain drag or hammer to locate hollow, unbonded, or debonded areas.
• CSP: concrete surface profile per ICRI 310.2R, numbered 1 (nearly flat) through 10 (very rough).

1.5 Submittals

• Existing conditions report per Article 3.1: sounding survey, crack map, moisture test results, and photographs.
• Overlay product data, including minimum and maximum placement thickness, compressive strength, and cure schedule.
• Repair mortar product data for crack and spall repair.
• Mockup: [50] square feet minimum on the project slab, demonstrating the scheduled finish, color, and pattern.
• Bond test results per ASTM C1583 where required by Article 3.2.

1.6 Quality assurance

• Installer qualifications: minimum [3] years placing bonded cementitious overlays, with references for the scheduled finish.
• The approved mockup is the standard of comparison for the remaining work. Protect the mockup until Substantial Completion.

1.7 Project conditions

• Substrate and ambient temperature within the overlay manufacturer limits during placement and cure.
• Building enclosed and the work area free of other trades from preparation through cure.
• Existing floor coverings, adhesives, coatings, and curing compounds removed before evaluation is finalized.

1.8 Warranty on the installed work

• Workmanship warranty on the resurfacing work as stated on the accepted proposal. This section carries no representation about the remaining service life of the existing slab beneath the overlay.

Part 2: products

2.1 Basis of design

The basis of design is the Bel Covo overlay family: a basic cementitious overlay for surface restoration, a patterned overlay for stamped and scored decorative work, and a polishable overlay formulated to receive the mechanical polishing specified in Section 03 35 43. Equivalent systems that meet the requirements of this section may be submitted for approval.

2.2 Overlay systems

Select the system by the scheduled finish. A polished result requires an overlay formulated and placed thick enough to survive the diamond progression; a basic overlay ground to the same schedule will not.

2.3 Bonding agent and primer

Bonding agent or slurry primer as required by the overlay manufacturer for the measured substrate condition and profile.

2.4 Repair materials

• Crack repair: low-viscosity resin injection for structurally sound cracks, or rout and fill with a polymer repair mortar where the crack is stable and non-moving.
• Spall and delamination repair: polymer-modified repair mortar compatible with the overlay above it.
• Moving joints: honor through the overlay per Article 3.5; do not fill a moving joint with repair mortar.

2.5 Sealers and finish materials

Sealer, stain, dye, or curing product compatible with both the overlay and the scheduled finish. Where the overlay is scheduled for polishing, no film-forming sealer is applied before the polishing scope.

Part 3: execution

3.1 Examination and existing conditions

Before any preparation, evaluate and document the existing slab:

1. Sounding survey. Locate delaminated and hollow areas by chain drag or hammer. Mark and quantify.
2. Crack map. Record crack locations, widths, and evidence of movement or differential elevation across the crack.
3. Moisture. Test per ASTM F1869 [3 lb/1,000 SF/24 hr maximum] or ASTM F2170 [80 percent RH maximum].
4. Contamination. Test for existing sealers, curing compounds, adhesives, and oil penetration.
5. Grade. Record deviations from grade: any change in floor grade exceeding a 4 percent slope between two adjacent grade points. An overlay is itself a remediation option for an out-of-grade slab, and the placement thickness plan must address each recorded deviation.

Report conditions that make resurfacing unsuitable before preparation begins. A slab with active differential settlement, widespread delamination, or unresolved moisture intrusion is a replacement candidate, not an overlay candidate, and an overlay placed over it will telegraph the same defects within a season.

Each step below states its objectives, its hazards, and the key best practices and methods that matter to the end result.

3.2 Preparation

Objectives:

• The profile the overlay manufacturer requires [CSP 3 to 5], with all unsound concrete removed down to sound material.

Hazards:

• An overlay placed over delaminated or contaminated substrate bonds to the defect, not to the slab.

Key best practices and methods:

• Mechanically prepare by diamond grinding, shot blasting, or scarifying, verified against an ICRI comparator.
• Where required, verify bond by ASTM C1583 pull-off testing at [3] locations minimum.
• Vacuum and clean the prepared surface immediately before priming.

3.3 Repair

Objectives:

• Cracks and spalls repaired per Article 2.4 and cured before overlay placement.

Hazards:

• Repair work is corrective, not cosmetic: a crack repaired without addressing its cause reappears through the overlay.

Key best practices and methods:

• Allow repair materials to cure per manufacturer instructions before placement.

3.4 Overlay placement

Objectives:

• A bonded overlay at the scheduled thickness, ready to receive the scheduled finish.

Hazards:

• Do not feather a polishable overlay to a thickness the polish schedule will cut through.
• Do not exceed the manufacturer open time between primer and placement.

Key best practices and methods:

• Apply the bonding agent or slurry primer and place the overlay within the open time.
• Work patterned overlays while plastic to the approved mockup pattern and texture.
• Cure per the manufacturer instructions, using a method compatible with the scheduled finish.

3.5 Joints

Objectives:

• All existing moving joints and control joints honored through the overlay at the same locations.

Hazards:

• Do not bridge a moving joint with overlay material.

Key best practices and methods:

• Fill honored joints with the scheduled joint filler after the overlay cures.

3.6 Finishing

Objectives:

• The scheduled finish applied to the cured overlay.

Hazards:

• A tooling schedule prepared for parent concrete does not transfer to an overlay substrate.

Key best practices and methods:

• Where the schedule calls for mechanical polishing, execute per Section 03 35 43 with a tooling schedule prepared for the overlay.

3.7 Field quality control

Sound the cured overlay for delamination before the finish is applied. Repair hollow areas and re-sound before proceeding.

3.8 Protection

Protect the finished surface from traffic and staining until full cure. Prohibit acids, harsh cleaners, and taped coverings that leave adhesive residue.

Which overlay system fits the slab?

The three systems differ by what finish they are built to carry, not by quality tier:

• Basic overlay restores surface condition on a sound slab that has spalled, crazed, or worn. It takes a sealed, exposed, or coated finish.
• Patterned overlay is worked while plastic into a stamped, scored, or textured pattern. It is the decorative system for patios, entries, and feature areas.
• Polishable overlay goes down at the thickness a diamond progression requires, so a slab that cannot be polished directly can still reach a polished floor.

All three place over a prepared substrate at CSP 3 to 5, and all three honor existing moving joints through the overlay. What changes is the formulation and the placement thickness, both driven by the finish scheduled above.

When does a slab need replacement instead?

An overlay bonds to what is under it and inherits its problems. Three findings in the examination article point to replacement rather than resurfacing: active differential settlement, widespread delamination, and moisture intrusion that has not been resolved at the source. Placing a bonded layer over any of the three buys a season of appearance and then reproduces the original defect through the new surface.

That call belongs in the existing conditions report, before anyone prices an overlay. Where replacement is the answer, Section 03 30 00 covers placing the new slab to the tolerance its finish will need.

From the field

Concrete overlays we installed

Related documents

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