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Polished Concrete Floors in San Francisco, CA
A polished concrete floor is a slab ground, densified and honed with abrasive tooling to a specified gloss, and in this city the outcome hangs on how hard and sound the old slab is, which gloss and stone exposure you pick, and how grinding dust is kept down indoors. Some of the city's candidate slabs are old and industrial: SF Planning hosts the Showplace Square context statement, which says concrete "dominated industrial architecture in the survey area into the early 1950s," and Planning Code section 210.3 says production, distribution and repair (PDR) businesses generally need space with "floors capable of bearing heavy loads." Grinding raises silica dust, which Cal/OSHA regulates under Title 8, section 1532.3. Angi's and HomeAdvisor's 2026 surveys price the work nationally at $2 to $16 a square foot, and none publishes a San Francisco figure.
Basic polished finishes: $3 to $12 a sq ft, national (HomeGuide, February 2026) · full pricing guide
No survey prices polishing in San Francisco; these figures are national. HomeGuide, in a survey dated February 8, 2026, charts the two choices an owner makes. Gloss climbs in price from a soft matte at $3 to $6 a square foot to high gloss at $6 to $15; stone exposure climbs from a cream finish at $3 to $8 to full aggregate at $6 to $12. Its overall band is $3 to $12 for basic work, with decorative floors at $5 to $15 or more, and small jobs often cost more per foot: under 1,000 square feet, $8 to $15 or more. In Angi's April 2026 survey, labor often makes up 60% to 70% of the total, and a slab on an upper floor runs $5 to $12 against $3 to $8 at ground level. The national cost ranges compare the surveys.
A polish is the slab cut and refined, not a layer laid over it. The ASCC Concrete Polishing Council's glossary describes "mechanically grinding, honing, and polishing" the surface, and Joint ACI-ASCC Committee 310 wrote the specification, ACI SPEC-310.1-20, covering "slabs-on-ground and suspended slabs." Partway through, a densifier goes on, a silicate solution that reacts in the surface "to produce additional calcium silicate hydrate (CSH)"; the 2009 Concrete International article hosted by ASCC applies it after the 80 or 150 grit pass. A dye can add color for $1 to $3 a square foot nationally in HomeGuide's February 2026 survey; the stained concrete floors page covers dyes. One label on a quote deserves a second look: Sherwin-Williams sells "Resuflor Grind and Seal" as a resin system on a CSP 1 profile, the smoothest of the ten concrete surface profiles in ICRI 310.2R, not as a polish.
Strength and surface decide whether a slab can be polished at all. For new work, the 2009 article judges "a well-proportioned mixture in the range of 3500 to 4000 psi (24 to 28 MPa)" to be "more than sufficient, especially when polishing commences at least 28 days after placement." For hardness, the Council's Position Statement #7 of August 2023 quotes ACI 310.1-20 Section 3.1.4.1, "Mohs Hardness measured on slab surface is greater than 4," a scratch test, and lists a densifier among the fixes for a soft top. Anything on the slab comes off first: Angi's April 2026 survey prices stripping carpet, adhesive or an old coating at $1 to $3 a square foot nationally. Repairs go early: as a general rule, Metzger/McGuire's Technical Bulletin T21 puts joint and crack work "prior to, or early on, in the concrete polishing process." The Dogpatch and Potrero Hill page describes that area's warehouse and PDR buildings.
Time follows the area, the last grit and the repairs. HomeGuide's February 2026 survey says "Most residential concrete polishing projects take 2 to 4 days for spaces up to 2,000 square feet" and "Commercial spaces of 5,000 to 10,000 square feet typically require 1 to 2 weeks," a survey's description rather than a promise. A polishable topping keeps its own clock: CTS says Rapid Set TRU Self-Leveling "may be polished wet or dry after 24 hours at normal conditions." Metzger/McGuire's Spal-Pro RS 88 joint filler is "TRAFFIC READY" in 1 hour at 70 degrees F and "will not smudge or smear during grinding/polishing." Dust control is the employer's duty under Cal/OSHA; daily dust mopping is yours once the crew leaves.
Expect a visit before a written quote, since hardness and cracks show only on the slab. Before it, note the floor's size, whether it sits on grade or upstairs, what covers it today, and which gloss level and stone class you are after, so competing quotes price one floor. In a loft or home, a contract over $500 counts as a home improvement contract under Business and Professions Code section 7159, which asks for "the significant materials to be used": list the densifier, any stain-protection coat, the last grit and the target gloss. Section 7159.5 caps any down payment at 10 percent of the contract amount or $1,000, whichever is less. A request sent from this page goes to an independent installer near you who holds a California contractor license, and the contract is signed with that installer.
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Signs a slab is ready to be ground and polished
A polish works with the concrete already in place, so the slab must be sound, hard and bare enough to cut. Each condition below can be checked on site. A slab that misses one may still be polished after a densifier, repairs or a polishable topping.
- The slab has passed 28 days since placement, the age the 2009 Concrete International article on specifying polished floors pairs with a mix strong enough to polish.
- A hardness check reads above 4 on the Mohs scale, the threshold the Council quotes from ACI 310.1-20 Section 3.1.4.1.
- The surface does not rub off as powder, the defect NRMCA's CIP 1 calls dusting, whose repair begins by removing the weak layer.
- Tapping or a chain drag finds no hollow spots, the sign NRMCA's CIP 20 gives for delaminated layers 1/8 to 1/4 inch thick.
- You accept the slab's own marks, since the gloss comes from the concrete's flat surface rather than a film, as Concrete Decor explains it.
- The floor can be dust mopped daily and cleaned without highly alkaline or acidic products, the care routine the 2009 article sets out.
A soft or heavily patched slab can still end up polished, under a cement topping laid thick enough to grind: 3/8 inch at the least for both Rapid Set TRU Self-Leveling and Euclid's Level Top Polish, by their makers' sheets. The concrete resurfacing page covers those toppings and the repairs beneath them.
Grit Stages, Gloss Levels and Aggregate Exposure Classes
A polished floor can be specified by two measured things, its gloss and how much stone shows, and both depend on how far the grinding goes. The Council's glossary splits the work into grinding, "any bonded abrasive that is 100 grit or lower"; honing, with "diamond tooling within the 100-400 grit range"; and polishing, at "800 grit or higher." In the 2009 article's typical sequence, 40 grit metal-matrix segments come first, then 80 and 150 grit, then resin pads climbing from 100 grit through 200, 400, 800 and 1500 to 3000, "with the 1500 and 3000 grit pads producing the highest sheen." The Council's appearance chart grades gloss by distinctness of image (DOI), how crisply a reflection resolves, with haze held under 12 throughout. Levels 1 and 2, flat and satin, read DOI 0 to 9 and 10 to 39.
At Level 3, DOI 40 to 69, reflected images "do not have a sharp and crisp appearance but can be identified"; past 70, at Level 4, they look "as would be seen in a near-mirror like reflection." An image clarity meter under ASTM D5767 takes the reading, which must be "measured before any post-polished surface treatments are added," so the level belongs to the concrete, not to a coating on top. A contract that names a level can be checked with a meter; a promise of a high shine cannot.
Silica Dust From Grinding: Cal/OSHA Title 8, Section 1532.3
Grinding concrete releases respirable crystalline silica, and for construction in California the governing rule is Cal/OSHA's: Title 8 of the California Code of Regulations, section 1532.3, effective October 17, 2016. Federal OSHA links the fine dust to silicosis, "an incurable lung disease," and to lung cancer. Section 1532.3(d)(1) bars exposure "in excess of 50 ug/m3, calculated as an 8-hour TWA," a time-weighted average, and the action level is 25 ug/m3 on the same basis; Table 1 sets controls tool by tool. A walk-behind floor grinder, row (xiii), either feeds water continuously to the cutting surface or carries the dust collection system its maker recommends, with a filter of "99% or greater efficiency and a filter-cleaning mechanism"; indoors, the crew must "use a HEPA-filtered vacuum to remove loose dust in between passes." With those controls, the table lists no respirator for either shift length.
Indoors, handheld grinders, row (xii), need a shroud and a collector giving "25 cubic feet per minute (cfm) or greater" of airflow per inch of wheel diameter, and past 4 hours a shift a respirator with an assigned protection factor (APF) of 10. Federal OSHA's rule, 29 CFR 1926.1153(f), bars dry sweeping or brushing that could expose workers unless safer methods are not feasible. Ask which method, collector and filter the crew will use.
Wet Slip Tests and Daily Care of a Polished Floor
A polished floor is not slick by nature, and the Council has test results to show it. Its Position Statement #2 (October 2017) set wet polished floors against the tile industry's threshold, a "minimum dynamic coefficient of friction of 0.42 for tiles in level indoor areas that may get wet in use," and reported: "All test results significantly exceeded the required DCOF of 0.42, even at very high gloss levels." Slip resistance, the statement adds, "does vary based on the gloss level," so ask for wet test results at the gloss level you choose. Wet days are routine here: NOAA's 1991-2020 normals for the Downtown station count 44.7 days a year with 0.10 inch or more of precipitation.
Care keeps the gloss. "Like any finished flooring or floor covering, polished concrete requires maintenance," says a Concrete Construction article the Council lists, and the 2009 article sets the routine: "daily dust mopping," because "Dirt and grime can dull a polished floor quickly by abrading the surface." The same article warns against cleaners "that are highly alkaline or acidic," which dull the floor quickly.
Polish the slab, top it first, or coat it instead
The slab's condition and the room's use decide. Polishing keeps the concrete as the wearing surface, a topping replaces a surface too damaged to polish, and a resin coating covers the slab with a film. Each route below carries its national survey price.
Cream or salt-and-pepper polish
A shallow cut keeps the cement paste on top. On the Council's aggregate exposure chart (February 2024), Class A, the cream finish, is 85 to 95 percent cement fines, and Class B, salt and pepper, is 85 to 95 percent fine aggregate; HomeGuide (February 2026) prices them at $3 to $8 and $4 to $10 a square foot. It suits a flat, sound loft or office slab where an even tone matters more than stone.
Full aggregate exposure
A deeper cut opens the coarse stone: Class C is 80 to 90 percent full aggregate, at $6 to $12 a square foot in HomeGuide's February 2026 survey, and HomeAdvisor's June 2026 page adds $3 to $5 a square foot for each additional grinding pass. Grip does not suffer, since Position Statement #2 found slip resistance "is not affected by the aggregate exposure class." It suits a shop or showroom slab whose stone is worth seeing.
Polishable topping, then polish
A cement topping gives a worn or patched slab a new surface. CTS says Rapid Set TRU Self-Leveling "can be ground and polished to a high-gloss appearance" over a CSP 3 to 5 profile and an epoxy primer with sand broadcast to refusal, and warns that "Reflective cracks may appear" over joints and cracks below. It suits a slab too soft or scarred to polish, where the budget allows a second layer.
A resin coating instead
An epoxy film covers the slab and adds color but brings a coating's moisture rules; Sherwin-Williams' Form G-1 says excess moisture can cause "delaminating of non-permeable resinous systems." Angi's July 2026 comparison prices epoxy jobs at $2,000 to $4,500 nationally, against $400 to $32,000 for a polish. It suits a lab or workshop where chemicals or color decide; the commercial epoxy flooring page covers those systems.
Polished Concrete Floors FAQs
How much is polished concrete per square foot in San Francisco?
Nationally, a polished floor runs about $2 to $16 a square foot in the 2026 surveys, and none prices San Francisco. Angi (July 2026) and HomeAdvisor (June 2026) both print $2 to $16, HomeGuide (February 2026) gives $3 to $12 for basic finishes, and This Old House (April 2026) gives $3 to $15. Gloss, stone exposure, size, access and repairs decide where a job lands; HomeGuide says hard-to-reach spaces such as basements may cost 10% to 30% more and puts 200 square feet at $1,600 to $3,000.
Is polished concrete better than epoxy?
Neither is better everywhere: polishing makes the slab the floor, while epoxy covers it with what Angi's polishing survey calls a "High-gloss, chemical-resistant finish." A film needs a dry, profiled slab, and ICRI's example for a high-build coating is CSP 3 to 5. A polish needs a hard, sound slab and leaves its marks visible, so it suits a slab worth showing; a coating suits chemicals, spills or color.
How long does polished concrete last?
The surveys give long spans, as survey wording rather than a maker's rating: HomeAdvisor's June 2026 page says polished floors "last 20 years or more when installed," and Angi's July 2026 comparison table says "Up to 50 years (well-maintained)." Grit and harsh cleaners wear the shine, the 2009 Concrete International article says. Angi's April 2026 page expects most homes to repolish "every three to five years," so plan for upkeep, not a single job.
Does polished concrete need to be sealed?
The surveys expect resealing, though the shine itself needs no coating: the densifier reacts in the surface of the concrete. The ASCC Concrete Polishing Council's glossary defines semi-impregnating stain protection as leaving "a protective surface film of less than 0.5 mils." In the Bay Area, a product labeled and formulated as a concrete or masonry sealer is held to 100 grams of VOC per liter by the Air District's Regulation 8, Rule 3. This Old House (April 2026) says resealing every 3 to 5 years is usually sufficient.
Does polishing concrete in California need a licensed contractor?
Yes, for any job of $1,000 or more in labor and materials, and for smaller ones that need a permit or hired help. Business and Professions Code section 7048 places a project totaling less than $1,000 outside the contractor law only when no building permit is required, and CSLB's bulletin #24-07 says hiring workers ends the exemption. CSLB's D-6 Concrete Related Services description includes "floor hardening treatment, coloring concrete, concrete restoration" in its work. CSLB and the statutes have the final word; the hiring guide shows how to check a license.
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