+---
+title: Concrete Curing and Finishing
+category: Structural / Concrete
+toc_depth: 3
+description: >
+ When to use: curing methods, materials, and duration plus surface finishing for cast-in-place
+ concrete placements - structural slabs, elevated decks, walls, columns, footings, grade beams,
+ and site flatwork. Covers wet cure, sheet cure, membrane-forming curing compounds (ASTM C309,
+ C1315), temperature-protection blankets, formed-surface curing, the finishing-to-curing
+ transition, the full range of surface finishes (screed, broom, float, steel-trowel, exposed
+ aggregate, rock salt, swirl, formed), FF/FL flatness and levelness tolerances per ACI 117, and
+ surface-defect acceptance and remediation.
+ Not intended for: mix design, placement, consolidation, and reinforcement (sync/cast-in-place-concrete);
+ subgrade, vapor retarder, and structural slab design (sync/slab-on-grade); formwork design,
+ shoring, and stripping (sync/concrete-formwork); reinforcement detailing (sync/concrete-reinforcement);
+ mechanical grinding, densification, and polishing of a hardened slab (sync/polished-concrete);
+ resinous floor coatings over cured concrete (sync/resinous-flooring); plant-cast precast curing;
+ highway/DOT pavement; and decorative stamped/stenciled architectural finishes.
+---
+
+# Scope {toc}
+
+## This standard governs the curing and surface finishing of cast-in-place concrete after placement and consolidation, including curing method selection, curing materials, curing duration, the transition from finishing to curing on flatwork, surface finish types, FF/FL flatness and levelness tolerances, and acceptance and remediation of surface defects. {note}
+
+## Curing and finishing are the execution layer that determines whether a structurally sound placement becomes a durable, serviceable surface. Inadequate curing reduces near-surface strength, abrasion resistance, and durability; poor finishing produces dusting, scaling, curling, and flooring failures. Most curing and finishing defects are irreversible once the concrete hardens, which is why they are specified and inspected as their own discipline rather than left to field discretion. {note}
+
+## This standard is the curing-and-finishing companion to [[sync/cast-in-place-concrete]], which governs materials, mix design, placement, and consolidation; this standard begins where that one ends - at the moment finishing operations start. {note}
+
+## The following adjacent topics are excluded from this standard and are governed by the standards noted; where this standard addresses a related surface condition, only the curing-and-finishing aspect is treated here: {note}
+- Mix design, placement, consolidation, and reinforcement of the concrete - [[sync/cast-in-place-concrete]] and [[sync/concrete-reinforcement]].
+- Subgrade preparation, vapor retarder selection, and structural design of slabs-on-grade - [[sync/slab-on-grade]].
+- Formwork design, erection, shoring, reshoring, and stripping sequence - [[sync/concrete-formwork]] (this standard addresses only curing of surfaces after stripping and the dependency of stripping time on the curing plan).
+- Mechanical grinding, chemical densification, diamond polishing, and topical sealing of a hardened slab - [[sync/polished-concrete]] (this standard addresses the pre-placement curing-compound compatibility decision when polishing is the intended finish).
+- Resinous and other bonded floor coatings applied over cured concrete - [[sync/resinous-flooring]] (this standard addresses only the substrate surface finish and curing those coatings require).
+- Plant-cast precast curing, highway and DOT pavement curing per FHWA/AASHTO specifications, and decorative architectural finishes such as stamping and stenciling - outside this standard's scope.
+
+# Referenced Standards {toc}
+
+## Curing, finishing, and tolerance work shall comply with the latest adopted edition of each of the following unless a specific edition is cited in the Contract Documents.
+
+## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ACI SPEC-308.1-23 | Specification for External Curing of Concrete |
+| ACI 308R-16 | Guide to External Curing of Concrete |
+| ACI 301-20 | Specifications for Concrete Construction |
+| ACI 302.1R-15 | Guide to Concrete Floor and Slab Construction |
+| ACI 117-10 (R2015) | Specification for Tolerances for Concrete Construction and Materials |
+| ACI 305R-20 | Guide to Hot Weather Concreting |
+| ACI 306R-16 | Guide to Cold Weather Concreting |
+| ASTM C309-19 | Liquid Membrane-Forming Compounds for Curing Concrete |
+| ASTM C1315-19 | Liquid Membrane-Forming Compounds Having Special Properties for Curing and Sealing Concrete |
+| ASTM C156-21 | Water Loss Through Liquid Membrane-Forming Curing Compounds |
+| ASTM C1064/C1064M-21 | Temperature of Freshly Mixed Hydraulic-Cement Concrete |
+| ASTM E1155-14 (R2019) | Determining FF Floor Flatness and FL Floor Levelness Numbers |
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following action submittals for review before any concrete subject to this standard is placed:
+- Curing plan identifying the curing method for each surface type (flatwork, formed vertical, elevated deck) and the proposed curing duration.
+- Product data for each proposed curing compound, sheet material, blanket, and evaporation retarder, with manufacturer certification of compliance with the referenced ASTM specification.
+- Manufacturer water-retention test data per ASTM C156 confirming the minimum 90% efficiency for each membrane-forming curing compound.
+- Compatibility statement confirming the selected curing method is compatible with the scheduled floor finish (polished concrete, tile, resilient flooring, resinous coating) for each slab.
+- Surface finish schedule listing the required finish for each slab, deck, and formed surface keyed to the drawings.
+- Hot weather and cold weather protection plans where placement is anticipated outside 40°F to 90°F ambient.
+
+```datasheet
+label: Action submittals required
+type: checkbox
+options:
+ - Curing plan (method and duration by surface)
+ - Curing material product data and ASTM certification
+ - ASTM C156 water-retention test data
+ - Floor-finish compatibility statement
+ - Surface finish schedule
+ - Hot weather protection plan
+ - Cold weather protection plan
+default:
+ - Curing plan (method and duration by surface)
+ - Curing material product data and ASTM certification
+ - ASTM C156 water-retention test data
+ - Floor-finish compatibility statement
+ - Surface finish schedule
+```
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following informational submittals during the work:
+- Daily curing log recording placement date, curing start time, method applied, and curing termination date for each placement.
+- Fresh concrete temperature records per ASTM C1064 for placements made under hot or cold weather conditions.
+- Evaporation rate determinations per the ACI 305 nomograph for placements where the rate is expected to approach the protective-measure threshold.
+- FF/FL flatness and levelness measurement reports per ASTM E1155 for each slab where F-numbers are specified.
+
+```datasheet
+label: Informational submittals required
+type: checkbox
+options:
+ - Daily curing log
+ - Fresh concrete temperature records
+ - Evaporation rate determinations
+ - FF/FL measurement reports
+default:
+ - Daily curing log
+ - FF/FL measurement reports
+```
+
+# Quality Assurance {toc}
+
+## The Contractor shall designate a competent finisher responsible for the timing of finishing operations and the transition to curing on all flatwork.
+
+## A pre-placement conference shall be held to confirm the curing method, curing duration, finish schedule, and protective measures for anticipated weather before the first placement subject to this standard.
+
+## Finishing operations shall not begin until bleed water has risen and evaporated from the surface.
+
+## Floating or troweling concrete that still carries surface bleed water seals water beneath the finished surface and causes delamination, dusting, and scaling. {note}
+
+## Curing shall begin immediately after final finishing of each surface, or immediately after form removal for surfaces cured after stripping; any interruption in moisture protection during the curing period shall be recorded and corrected.
+
+## FF/FL flatness and levelness shall be measured within 72 hours of finishing and before removal of supporting shores, in accordance with ACI 117 Section 4.8.4.1.
+
+## FF/FL measured after 72 hours captures slab curling rather than as-finished flatness and is not an acceptable basis for acceptance; curling that develops after finishing cannot be reversed. {note}
+
+# Curing Fundamentals {toc}
+
+## Curing is the maintenance of moisture and temperature in concrete during the period after placement so that cement hydration continues and the concrete develops its designed strength, durability, and abrasion resistance. Curing is not the same as drying: curing keeps water in the concrete for hydration, while drying removes free water from a cured slab to receive a moisture-sensitive floor covering. The two are sequential operations and must both be specified when a slab will receive flooring. {note}
+
+## Concrete shall be cured continuously throughout the specified curing period; the surface shall not be permitted to dry out at any time during that period.
+
+## The curing period shall be measured from the time finishing is complete (for flatwork) or from the time of placement (for formed surfaces), not from the time the curing material is applied.
+
+## Confusing curing with drying is a recurring cause of flooring failure attributed to a "bad slab": a properly cured slab still requires a drying period before moisture-sensitive flooring, and omitting that period from the specification transfers a curing success into a flooring failure. {note}
+
+# Curing Method Selection {toc}
+
+## The available curing methods are wet curing (continuous water saturation, wet burlap, or soaker hoses), sheet curing (polyethylene film or wet burlap-polyethylene laminate), liquid membrane-forming curing compounds, temperature-protection curing blankets, and formed-surface curing (forms left in place). Each provides moisture retention; the selection is driven by surface type, the scheduled floor finish, and the ambient conditions during the curing period. {note}
+
+## The curing method for each surface shall be selected for compatibility with the scheduled floor finish; an incompatible method that must later be removed is a defect, not an alternative.
+
+```datasheet
+label: Primary curing method - interior flatwork
+type: radio
+options:
+ - Wet cure (saturated burlap, kept continuously wet)
+ - Polyethylene sheet (over wet surface or wet burlap)
+ - Liquid membrane-forming compound (ASTM C309)
+ - Cure-and-seal compound (ASTM C1315)
+ - Wet cure followed by dissipating compound
+default: Liquid membrane-forming compound (ASTM C309)
+```
+
+```datasheet
+label: Primary curing method - formed vertical surfaces
+type: radio
+options:
+ - Leave forms in place for the curing period
+ - Strip forms, then apply membrane-forming compound immediately
+ - Strip forms, then wet cure
+default: Leave forms in place for the curing period
+```
+
+## Curing Compound Compatibility with Floor Finishes {toc}
+
+### A permanent membrane-forming curing compound forms a film on the concrete surface that prevents bond of polished-concrete densifiers, tile thin-set, self-leveling underlayment, resilient flooring adhesive, and resinous coatings; if applied to a slab scheduled for any of these finishes, the film must be mechanically removed before the finish is installed, adding cost and schedule. {note}
+
+### Where a slab is scheduled to receive polished concrete, ceramic or stone tile set in thin-set, resilient flooring, or a resinous coating, a permanent white-pigmented membrane-forming compound (ASTM C309 Type 2) shall not be used.
+
+### Slabs scheduled to receive a bonded floor finish shall be wet cured, sheet cured, or cured with a dissipating or water-based compound verified by the finish manufacturer as compatible with the scheduled finish.
+
+### The curing-compound decision for a slab scheduled for polishing is made before placement and is governed jointly by this standard and [[sync/polished-concrete]]; coordinate the two so the curing method on the structural drawings matches the finish on the architectural drawings. {note}
+
+### Curing-compound compatibility shall be coordinated across the structural and architectural drawing packages so the curing requirement and the floor-finish requirement reference each other; a compound selected without reference to the scheduled finish is the single most common curing defect.
+
+```datasheet
+label: Scheduled floor finish (drives compound selection)
+type: select
+options:
+ - Bare concrete (no covering)
+ - Sealed concrete
+ - Polished concrete
+ - Tile (thin-set)
+ - Resilient flooring (sheet, tile, plank)
+ - Resinous or epoxy coating
+ - Carpet
+default: Sealed concrete
+```
+
+```datasheet
+label: Compound permanence permitted by finish
+type: radio
+options:
+ - Permanent residual film acceptable
+ - Dissipating or removable film required
+ - No film permitted (wet or sheet cure only)
+default: Permanent residual film acceptable
+```
+
+# Curing Materials {toc}
+
+## Liquid Membrane-Forming Curing Compounds {toc}
+
+### Liquid membrane-forming curing compounds shall comply with ASTM C309 and shall achieve a minimum water-retention efficiency of 90% when tested per ASTM C156.
+
+### ASTM C309 classifies compounds as Type 1 (clear or translucent), Type 1-D (clear with fugitive dye for application visibility), and Type 2 (white-pigmented to reduce solar heat gain on sun-exposed surfaces). The fugitive dye in Type 1-D verifies uniform coverage and fades within a few days; it does not affect the cured appearance. {note}
+
+### Cure-and-seal compounds, where a residual sealer on the finished surface is acceptable, shall comply with ASTM C1315 and shall be used only where the scheduled floor finish permits a residual film.
+
+### A cure-and-seal compound (ASTM C1315) leaves an acrylic sealer on the surface and is appropriate for exposed sealed concrete; it is a residual film and is therefore subject to the same finish-compatibility restriction as a permanent C309 Type 2 compound. {note}
+
+### Curing compound shall be applied at a coverage rate not exceeding 200 sq ft/gal per coat; high-absorption or textured surfaces shall receive two coats applied at right angles, each at no more than 200 sq ft/gal.
+
+### Curing compound shall not be applied until the bleed water sheen has disappeared from the surface; applying compound over standing bleed water traps water beneath the membrane and delaminates the surface paste layer.
+
+### Curing compound shall not be applied when the air or surface temperature is below 40°F, because solvent- and water-based compounds will not form a continuous film below that temperature.
+
+```datasheet
+label: Curing compound type (ASTM C309)
+type: radio
+options:
+ - Type 1 - clear or translucent
+ - Type 1-D - clear with fugitive dye
+ - Type 2 - white-pigmented
+default: Type 1-D - clear with fugitive dye
+```
+
+```datasheet
+label: Curing compound specification class
+type: radio
+options:
+ - ASTM C309 - curing only
+ - ASTM C1315 Type I - cure and seal, clear
+ - ASTM C1315 Type I-D - cure and seal, with dye
+default: ASTM C309 - curing only
+```
+
+```datasheet
+label: Curing compound coverage rate (max per coat)
+type: range
+unit: sq ft/gal
+min: 150
+max: 250
+step: 25
+default: 200
+```
+
+```datasheet
+label: Number of curing compound coats
+type: radio
+options:
+ - One coat
+ - Two coats at right angles
+default: One coat
+```
+
+## Sheet and Wet Curing Materials {toc}
+
+### Polyethylene curing sheet shall be clear or white film of nominal 6-mil thickness, placed over the wetted surface or over saturated burlap, lapped at joints, and weighted or taped to prevent moisture loss and wind uplift.
+
+### White polyethylene sheet should be used in lieu of clear film on sun-exposed placements to reduce solar heat gain and the discoloration that mottled clear-film contact can cause.
+
+### Burlap-polyethylene laminate curing blankets shall be pre-soaked before placement and kept continuously in contact with the surface for the curing period.
+
+### Wet curing by saturated burlap or soaker hose shall keep the surface continuously moist for the full curing period.
+
+### Intermittent wetting that allows the surface to dry between applications causes surface crazing and is not continuous curing. {note}
+
+```datasheet
+label: Polyethylene curing sheet
+type: radio
+options:
+ - 6-mil clear
+ - 6-mil white
+default: 6-mil clear
+```
+
+```datasheet
+label: Wet curing material
+type: select
+options:
+ - Saturated burlap, kept wet
+ - Burlap-polyethylene laminate blanket
+ - Soaker hose with continuous flow
+ - Cotton mats
+default: Saturated burlap, kept wet
+```
+
+## Temperature-Protection Blankets and Evaporation Retarders {toc}
+
+### Insulated curing blankets shall be R-value rated for the protection required by the cold weather plan and shall be lapped and secured to prevent heat loss at edges and penetrations.
+
+### Evaporation retarder shall be a monomolecular film applied by spray to the screeded surface to slow moisture loss in hot or windy conditions before final finishing; it is a finishing aid against plastic shrinkage cracking and shall not be used as a curing compound or worked into the surface as a finishing lubricant.
+
+```datasheet
+label: Cold weather protection blanket R-value (per inch)
+type: range
+unit: R per in
+min: 2
+max: 8
+step: 1
+default: 4
+```
+
+```datasheet
+label: Evaporation retarder required
+type: radio
+options:
+ - Required when evaporation rate may exceed threshold
+ - Required for all exterior placements
+ - Not required
+default: Required when evaporation rate may exceed threshold
+```
+
+# Curing Duration {toc}
+
+## The minimum curing duration depends on the cementitious system: Type I/II portland cement develops adequate near-surface properties in 7 days of moist curing, Type III high-early-strength cement in 3 days, and blends with significant slag or fly ash replacement require 10 to 14 days because their pozzolanic reactions proceed more slowly. Cold weather extends every duration because hydration slows with temperature. {note}
+
+## Type I or Type II portland cement concrete shall be cured for a minimum of 7 days.
+
+## Type III high-early-strength concrete shall be cured for a minimum of 3 days.
+
+## Concrete with slag or fly ash replacement exceeding 25% of cementitious content shall be cured for a minimum of 10 days, extended to 14 days where durability or low permeability is required.
+
+## The curing duration shall not be reduced by the early attainment of design strength.
+
+## The curing period protects the near-surface zone, which lags the core in strength and durability and benefits from the full period regardless of cylinder breaks. {note}
+
+```datasheet
+label: Minimum curing duration
+type: select
+options:
+ - 3 days (Type III high-early)
+ - 7 days (Type I/II portland)
+ - 10 days (slag/fly-ash blend)
+ - 14 days (high durability or low permeability)
+default: 7 days (Type I/II portland)
+```
+
+```datasheet
+label: Cementitious system (drives duration)
+type: radio
+options:
+ - Type I/II portland cement
+ - Type III high-early-strength cement
+ - Portland with fly ash > 25%
+ - Portland with slag > 25%
+default: Type I/II portland cement
+```
+
+# Hot Weather Curing {toc}
+
+## In hot, dry, or windy conditions the rate of surface evaporation can exceed the rate at which bleed water rises, drying the surface and causing plastic shrinkage cracking before the concrete sets. The ACI 305 nomograph relates air temperature, concrete temperature, relative humidity, and wind speed to an evaporation rate; protective measures are triggered when that rate exceeds 0.20 lb/ft²/hr. Plastic shrinkage cracks are irreversible, so the trigger and the response must be specified before placement, not negotiated after cracks appear. {note}
+
+## Where the evaporation rate determined from the ACI 305 nomograph exceeds 0.20 lb/ft²/hr, protective measures shall be implemented before and during finishing.
+
+## Hot weather protective measures shall include one or more of the following as required to control evaporation: fogging upwind of the placement, erection of windbreaks, sun shading, application of evaporation retarder, and scheduling the placement for night or early morning.
+
+## Fresh concrete temperature at the point of discharge shall not exceed 95°F unless a lower limit is specified for mass or high-performance concrete.
+
+## Curing shall begin as early as finishing permits in hot weather.
+
+## The period between final finishing and the start of curing is when surface drying does the most damage. {note}
+
+```datasheet
+label: Evaporation rate trigger for protective measures
+type: range
+unit: lb/ft²/hr
+min: 0.10
+max: 0.30
+step: 0.05
+default: 0.20
+```
+
+```datasheet
+label: Maximum fresh concrete temperature at discharge
+type: range
+unit: °F
+min: 85
+max: 95
+step: 5
+default: 95
+```
+
+```datasheet
+label: Hot weather protective measures
+type: checkbox
+options:
+ - Fogging upwind of placement
+ - Windbreaks
+ - Sun shading
+ - Evaporation retarder
+ - Night or early-morning placement
+default:
+ - Evaporation retarder
+ - Fogging upwind of placement
+```
+
+# Cold Weather Curing {toc}
+
+## In cold weather, hydration slows and stops as concrete approaches freezing, and concrete that freezes before reaching about 500 psi compressive strength suffers permanent disruption of its cement paste. Cold weather curing maintains the concrete above a minimum temperature long enough to develop strength and resist the first freeze. {note}
+
+## The concrete surface temperature shall be maintained at a minimum of 55°F throughout the protection period in accordance with ACI 306R.
+
+## The concrete shall not be permitted to freeze before it reaches a compressive strength of 500 psi.
+
+## Cold weather protection shall be provided by insulated blankets, heated enclosures, heated mix water, or a combination, as required to maintain the minimum surface temperature for the protection period.
+
+## Concrete temperature shall be monitored during the protection period; where strength confirmation is required before protection is removed, maturity or field-cured cylinder data shall be used rather than calendar days alone.
+
+```datasheet
+label: Minimum maintained surface temperature - cold weather
+type: range
+unit: °F
+min: 50
+max: 60
+step: 5
+default: 55
+```
+
+```datasheet
+label: Cold weather protection method
+type: checkbox
+options:
+ - Insulated curing blankets
+ - Heated enclosure
+ - Heated mix water
+ - Reflective foil-faced blankets
+default:
+ - Insulated curing blankets
+```
+
+```datasheet
+label: Cold weather strength confirmation method
+type: radio
+options:
+ - Maturity monitoring
+ - Field-cured cylinders
+ - Calendar days plus temperature log
+default: Maturity monitoring
+```
+
+# Formed-Surface Curing {toc}
+
+## Forms left in place provide effective curing for vertical and formed surfaces by retaining moisture against the concrete. When forms are stripped before the curing period ends, the freshly exposed surface dries rapidly and must be protected immediately - by wet curing or by applying a curing compound to the stripped surface - or the curing plan is voided at the moment of stripping. The minimum time forms remain in place is set by the lesser of the stripping schedule in [[sync/concrete-formwork]] and the curing requirement of this standard. {note}
+
+## Where forms are removed before the curing period is complete, the exposed surface shall be wet cured or shall receive a curing compound immediately, and the curing shall continue for the balance of the required period.
+
+## Forms shall remain in place for a minimum of 12 hours on non-structural surfaces and 24 hours on structural walls and columns before form removal for the purpose of applying a curing compound, except as the Engineer of Record directs for the specific mix and conditions.
+
+## The form-removal sequence shall be coordinated with the curing plan so that stripping does not interrupt the required curing period.
+
+## Stripping schedule and curing duration are coordinated requirements, not independent ones. {note}
+
+```datasheet
+label: Minimum form-in-place time before compound application
+type: select
+options:
+ - 12 hours (non-structural)
+ - 24 hours (structural walls and columns)
+ - Per Engineer of Record
+default: 24 hours (structural walls and columns)
+```
+
+# Surface Finishing {toc}
+
+## Surface finish is selected by the intended service of the surface: the type of traffic, the required slip resistance, and the floor covering or coating to be applied. A finish that is correct for one service is wrong for another - a hard steel trowel that is ideal for an exposed warehouse floor seals the surface against the bond that a tile or epoxy finish needs. The finish schedule must therefore name the finish for each surface by its service, not apply one finish everywhere. {note}
+
+## The Finish Schedule {toc}
+
+### Each surface shall receive the finish indicated in the finish schedule; where no finish is scheduled for an interior slab, a steel-troweled finish shall be provided, and where none is scheduled for an exterior slab, a broom finish shall be provided.
+
+### Finishing operations shall not begin until the bleed water sheen has left the surface; premature finishing seals bleed water under the surface and produces a weak, dusting wear layer. {note}
+
+```datasheet
+label: Interior slab finish
+type: select
+options:
+ - Rough screed (to receive topping or fill)
+ - Floated finish
+ - Light steel-trowel finish
+ - Hard steel-trowel finish
+ - Swirl finish
+default: Hard steel-trowel finish
+```
+
+```datasheet
+label: Exterior flatwork finish
+type: select
+options:
+ - Floated finish
+ - Light broom finish
+ - Medium broom finish
+ - Heavy broom finish
+ - Rock-salt texture
+ - Exposed aggregate
+default: Medium broom finish
+```
+
+```datasheet
+label: Formed (vertical) surface finish
+type: select
+options:
+ - As-cast rough form finish
+ - Smooth rubbed finish
+ - Grout-cleaned finish
+ - Sack-rubbed finish
+default: As-cast rough form finish
+```
+
+## Floated and Troweled Finishes {toc}
+
+### A floated finish shall be produced by floating the surface to a uniform, open texture after the bleed water has left and before troweling; the float finish is the substrate for troweling and for bonded toppings.
+
+### A light steel-trowel finish shall be produced by one or two trowel passes leaving a smooth surface with a slightly open texture, and shall be specified where a bonded coating, thin-set tile, or self-leveling underlayment will be applied.
+
+### A hard steel-trowel finish shall be produced by successive trowel passes producing a dense, burnished surface, and shall be specified for exposed wear surfaces not receiving a bonded finish.
+
+### A hard steel-trowel finish shall not be specified for a surface scheduled to receive a bonded coating or thin-set; over-troweling seals the paste layer and prevents adhesion of epoxy, thin-set, and self-leveling underlayment.
+
+### The distinction between light- and hard-trowel finishes is a bond decision, not only an appearance decision: the denser the troweled surface, the less it will accept a bonded overlay, so the finish must be matched to whether the surface stays bare or is later coated. {note}
+
+## Textured and Exterior Finishes {toc}
+
+### A broom finish shall be produced by drawing a broom across the floated surface transverse to the direction of traffic to provide slip resistance on exterior flatwork and ramps.
+
+### The broom-finish texture depth shall match the scheduled light, medium, or heavy designation.
+
+### An exposed-aggregate finish shall be produced by removing the surface mortar to reveal the coarse aggregate, by washing, brushing, or surface retarder, and the aggregate shall be specified for the finish appearance where this finish is used.
+
+### A rock-salt texture shall be produced by broadcasting and embedding rock salt into the fresh surface and washing it out after the concrete sets, leaving a pitted texture.
+
+### A rock-salt texture shall not be used in climates subject to freezing because the pits hold water that spalls on freezing.
+
+### A swirl finish shall be produced by a uniform overlapping arc pattern worked into the floated surface with a trowel or float to provide a decorative, slip-resistant texture.
+
+```datasheet
+label: Broom finish texture depth
+type: radio
+options:
+ - Light broom
+ - Medium broom
+ - Heavy broom
+default: Medium broom
+```
+
+```datasheet
+label: Broom direction
+type: radio
+options:
+ - Transverse to traffic
+ - Parallel to traffic
+default: Transverse to traffic
+```
+
+# Flatness and Levelness Tolerances {toc}
+
+## Floor flatness and levelness are specified by the F-number system: FF measures the bumpiness of the surface over short distances, and FL measures the tilt of the surface from a level plane over longer distances. Higher numbers are flatter and more level. The targets are set by the intended use and the floor covering, and they are organized by the floor classes of ACI 302.1R - from conventional slabs through office and retail floors to high-tolerance and super-flat warehouse floors. {note}
+
+## FF and FL values shall be specified as both an overall composite value and a minimum local value; a composite value alone can pass while localized humps or dips that will disturb a floor covering still exist.
+
+## FF flatness and FL levelness shall be measured in accordance with ASTM E1155 within 72 hours of finishing and before removal of supporting shores.
+
+## The specified F-numbers shall match the floor's intended use and covering per ACI 302.1R: conventional slabs at roughly FF 20 / FL 15, office and retail floors at FF 25 / FL 20, light-industrial warehouse floors at FF 35 / FL 25, and super-flat warehouse floors at FF 50 / FL 35 or higher. {note}
+
+## Where the specified F-numbers are not achieved, the affected area shall be remediated by grinding high spots or filling low spots with a compatible material, subject to the limits of the floor finish and the Engineer of Record's acceptance.
+
+```datasheet
+label: Overall flatness FF (composite)
+type: select
+options:
+ - FF 20 (conventional)
+ - FF 25 (office / retail)
+ - FF 35 (light-industrial warehouse)
+ - FF 50 (super-flat warehouse)
+default: FF 25 (office / retail)
+```
+
+```datasheet
+label: Overall levelness FL (composite)
+type: select
+options:
+ - FL 15 (conventional)
+ - FL 20 (office / retail)
+ - FL 25 (light-industrial warehouse)
+ - FL 35 (super-flat warehouse)
+default: FL 20 (office / retail)
+```
+
+```datasheet
+label: Minimum local FF
+type: range
+unit: FF
+min: 13
+max: 35
+step: 1
+default: 17
+```
+
+```datasheet
+label: Minimum local FL
+type: range
+unit: FL
+min: 10
+max: 25
+step: 1
+default: 15
+```
+
+## Formed-Surface Dimensional Tolerances {toc}
+
+### Variation from plumb of formed vertical surfaces shall not exceed 3/8 inch in 10 ft and 1/2 inch in any story, per ACI 117 Section 4.4.
+
+### Variation from level or specified grade of formed surfaces shall not exceed 3/8 inch in 10 ft.
+
+# Surface Defects and Remediation {toc}
+
+## Honeycombs, rock pockets, voids, and cold-joint blemishes on formed surfaces and surface defects on flatwork are inspected against defined acceptance limits and repaired by defined methods. Leaving the acceptance criteria undefined generates RFIs on nearly every placement and invites the wrong repair - painting over a void rather than filling it. The standard therefore states the size limits, the prohibited repairs, and the required repair methods. {note}
+
+## Formed surfaces shall be inspected after form removal, and surface defects shall be repaired before curing compound is applied or, for wet-cured surfaces, before the surface is sealed by finishing.
+
+## Honeycombs and voids shall be repaired by removing unsound concrete to a sound surface and filling by dry-pack mortar for shallow voids, epoxy injection for cracks, or form-and-pour for deep or large voids; the repair method shall be matched to the defect depth.
+
+## Surface voids and honeycombs shall not be concealed by parging, painting, or skim-coating over the unsound concrete; concealment hides a durability and reinforcement-cover defect rather than correcting it.
+
+## Defects that expose reinforcement or reduce concrete cover shall be referred to the Engineer of Record before repair.
+
+## Such defects may affect structural capacity and corrosion protection rather than only appearance. {note}
+
+## Plastic shrinkage cracks, crazing, dusting, and scaling are curing and finishing defects rather than structural defects; their appearance is evidence that the finishing-to-curing transition was mishandled. {note}
+
+## The acceptance or repair of plastic shrinkage cracks, crazing, dusting, and scaling shall be determined case by case against the cause.
+
+```datasheet
+label: Maximum acceptable surface void diameter (formed surfaces)
+type: range
+unit: in
+min: 0.25
+max: 1.5
+step: 0.25
+default: 0.75
+```
+
+```datasheet
+label: Honeycomb / void repair method
+type: select
+options:
+ - Dry-pack mortar (shallow voids)
+ - Epoxy injection (cracks)
+ - Form-and-pour (deep or large voids)
+ - Refer to Engineer of Record
+default: Dry-pack mortar (shallow voids)
+```
+
+# Drying Before Floor Coverings {toc}
+
+## Curing keeps water in the concrete; a moisture-sensitive floor covering needs the slab to be dry. After curing ends, a slab must lose enough internal moisture before resilient flooring, wood, or a moisture-sensitive adhesive is installed, or the trapped moisture will debond the covering and is then blamed on a "bad slab." Drying is a separate scheduled operation that follows curing. {note}
+
+## The specification shall require drying explicitly when the slab will receive a moisture-sensitive floor covering.
+
+## A slab scheduled to receive a moisture-sensitive floor covering shall be tested for internal relative humidity in accordance with ASTM F2170 before the covering is installed, and the covering shall not be installed until the measured internal relative humidity is at or below the covering manufacturer's limit.
+
+## The internal relative humidity limit shall be taken as 75% to 80% unless the floor-covering manufacturer specifies a different limit, in which case the manufacturer's limit shall govern.
+
+## A drying period shall be allowed after curing ends and before moisture testing; as a planning rule of thumb the period is on the order of 30 days per inch of slab thickness under favorable interior drying conditions, but the ASTM F2170 result, not the calendar, governs acceptance. {note}
+
+```datasheet
+label: Internal relative humidity limit (ASTM F2170)
+type: range
+unit: %
+min: 70
+max: 85
+step: 1
+default: 80
+```
+
+```datasheet
+label: Moisture testing required before floor covering
+type: radio
+options:
+ - Required for all moisture-sensitive coverings
+ - Required where indicated
+ - Not required (bare or non-sensitive finish)
+default: Required for all moisture-sensitive coverings
+```