Where the calculator constants come from

S1_GALLON_CUBIC_INCHES

231 cubic inches per US liquid gallon

Statements of fluid measure shall be in terms of both the U.S. gallon of 231 cubic inches and quart, pint, and fluid ounce subdivisions thereof and SI metric liters or milliliters

S2_MIL_INCHES

0.001 inch per mil

mil / mils The English measurement for 0.001 in or one one-thousandth of an inch.

Quoted from a federal construction specification rather than a dictionary, because the same document sets the substrate rules used elsewhere on this site.

S3_SLAB_ON_GRADE_CURE_DAYS

90 days of cure before a slab on grade is coated

Curing: Allow concrete, stucco and masonry surfaces to cure at least 30 days before painting, and concrete slab on grade to cure at least 90 days before painting.

Note the distinction the specification draws: 30 days for concrete generally, 90 for a slab on grade, because a slab on grade only dries upward.

S4_NO_EPOXY_ON_DAMP

1.000 prohibition (no numeric value)

Do not apply epoxies to damp surfaces as determined by ASTM D4263 .

Singled out because it names epoxy specifically and names a cheap test — a taped plastic sheet — that any homeowner can run the night before.

S5_CONCRETE_MAX_MOISTURE_PCT

12 percent moisture content by electronic meter

Maximum allowable moisture content of concrete is 12 percent. Measure moisture content with an electronic moisture meter.

A meter reading is a screen, not a substitute for a calcium chloride or in-situ probe test. It is quoted here because it is the only numeric moisture ceiling we found published in a document we could retrieve.

S6_SILICA_PEL

50 micrograms per cubic metre, 8-hour time-weighted average

The employer shall ensure that no employee is exposed to an airborne concentration of respirable crystalline silica in excess of 50 μg/m 3 , calculated as an 8-hour TWA.

S7_GRINDER_FILTER_EFFICIENCY_PCT

99 percent minimum filter efficiency on the dust collector

Dust collector must provide the air flow recommended by the manufacturer, or greater, and have a filter with 99% or greater efficiency and a filter-cleaning mechanism When used indoors or in an enclosed area, use a HEPA-filtered vacuum to remove loose dust in between passes

S8_HANDHELD_GRINDER_CFM_PER_INCH

25 cfm of extraction airflow per inch of wheel diameter

Dust collector must provide 25 cubic feet per minute (cfm) or greater of airflow per inch of wheel diameter and have a filter with 99% or greater efficiency and a cyclonic pre-separator or filter-cleaning mechanism

This is the row that governs edge work and corners, which is where a domestic project actually generates its dust.

S9_VOC_FLOOR_COATING_LIMIT

400 grams of VOC per litre of coating, less water and exempt compounds

Floor coatings 400 3.3

The second number in the quoted row, 3.3, is the same limit expressed in pounds per gallon. Several states and air districts set limits below the federal ceiling.

S10_VOC_INDUSTRIAL_MAINTENANCE_LIMIT

450 grams of VOC per litre of coating, less water and exempt compounds

Industrial maintenance coatings 450 3.8

Matters because many high-build resinous products are sold under the industrial-maintenance definition rather than the floor-coating one, and the two rows carry different ceilings.

S11_ADA_NO_COF_THRESHOLD

0.000 published minimum coefficient of friction (there is none)

the standards do not specify a minimum level of slip resistance (coefficient of friction) because a consensus method for rating slip resistance remains elusive

Quoted because it is the reason this site refuses to print a slip-resistance number. The federal body that writes the accessibility standard says a consensus method does not exist.

S12_ADA_SLIP_RESISTANT_REQUIREMENT

1.000 requirement (no numeric value)

Accessible floor and ground surfaces must be stable, firm, and slip resistant.

S13_ASTM_F1869

1,869 ASTM designation (title only; the standard text is not reproduced)

F1869 Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride

Cited for the existence and title of the method only. The body of an ASTM standard is copyrighted; nothing from inside it is reproduced or relied on here, and it publishes no pass/fail limit for a coating in any case.

S14_ASTM_F2170

2,170 ASTM designation (title only; the standard text is not reproduced)

F2170 Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes

Same limitation as F1869: title and existence only.

D1_SQFT_MIL_PER_GAL

1,604.1667 square feet at one mil, per gallon, at 100 percent volume solids

231 cubic inches per gallon ÷ 0.001 inch per mil = 231,000 square inches covered at one mil; 231,000 ÷ 144 square inches per square foot = 1,604.1667 square feet at one mil, per gallon.

Derived from: S1_GALLON_CUBIC_INCHES, S2_MIL_INCHES, DEFINITIONS.square_inches_per_square_foot

Usually quoted rounded to 1,604. This site keeps the full quotient and rounds once, at the end, because rounding a constant this load-bearing propagates into every gallon figure on the site.

D2_CUIN_PER_SQFT_MIL

0.144000 cubic inches of wet material per square foot per mil

144 square inches per square foot × 0.001 inch per mil = 0.144 cubic inches of material to cover one square foot at one mil.

Derived from: S2_MIL_INCHES, DEFINITIONS.square_inches_per_square_foot

The same fact as D1 seen from the other end. It is the form used by the crack and spall repair takeoff, which measures voids in cubic inches rather than in film thickness.

D3_GAL_PER_CUFT

7.4805 gallons per cubic foot

1,728 cubic inches per cubic foot ÷ 231 cubic inches per gallon = 7.4805 gallons.

Derived from: S1_GALLON_CUBIC_INCHES, DEFINITIONS.cubic_inches_per_cubic_foot

D4_VOC_HEADROOM_G_PER_L

50.0000 grams per litre of difference between the two applicable federal limits

450 grams per litre for industrial maintenance coatings − 400 grams per litre for floor coatings = 50 grams per litre.

Derived from: S9_VOC_FLOOR_COATING_LIMIT, S10_VOC_INDUSTRIAL_MAINTENANCE_LIMIT

Published because the category a product is sold under changes the ceiling it must meet, and the label rarely says which row it was certified against.

A1_POROSITY_LOSS_FRACTION

0.12 fraction of the first coat absorbed by an open profile

The share of the first coat that soaks into an opened concrete profile rather than building film is our own allowance, not a measured or published value.

How to replace it: Buy one kit, coat a measured ten-by-ten patch of the actual prepared slab, and work out your own real coverage before ordering the rest.

A2_MIXING_AND_WASTE_FRACTION

0.05 fraction lost to buckets, rollers and pot-life overruns

The five percent allowance for material left in the bucket, loaded into the roller cover, or kicked off in the pot before it could be spread is our own figure.

How to replace it: If you have poured a two-part product before, use what you actually wasted. Crews that pour into a second bucket and re-scrape lose noticeably less.

A3_CURE_HALVING_DEGF

18.0 degrees Fahrenheit of cooling that roughly doubles cure time

That cure time roughly doubles for every eighteen degrees Fahrenheit the slab is colder is a rule of thumb we are applying, not a property of your product.

How to replace it: Technical data sheets publish pot life and recoat windows at a stated temperature, and better ones publish a second column at a colder one. Use those two points instead of our rule.

A4_FLAKE_BROADCAST_LB_PER_100SQFT

4.0 pounds of decorative flake per 100 square feet at partial broadcast

The flake coverage used here is our own planning allowance for a partial broadcast; a full refusal broadcast uses several times more and manufacturers state their own rates.

How to replace it: Flake is sold with a stated coverage on the box. Use it, and buy one box more than the arithmetic says, because a thin patch cannot be fixed after the base coat gels.

A5_QUARTZ_BROADCAST_LB_PER_SQFT

1.1 pounds of quartz aggregate per square foot per broadcast course

The quartz broadcast rate is our own planning allowance per course, and a double-broadcast system applies it twice.

How to replace it: Quartz systems are normally specified by the resin manufacturer as a complete build, with the aggregate rate stated per course. Use their build sheet.

A6_GRIND_SQFT_PER_HOUR

180.0 square feet per machine-hour, single pass, walk-behind grinder

Grinding productivity is our own planning figure for one pass with a rented walk-behind machine on sound concrete; it is not a manufacturer rating.

How to replace it: The rental desk knows what their machine does on a domestic slab, and the tooling matters more than the machine. Ask, and ask what tooling they are supplying.

A7_SHOTBLAST_SQFT_PER_HOUR

500.0 square feet per machine-hour, single pass, walk-behind shot blaster

Shot-blast productivity is our own planning figure for one pass on open floor, and it is the number most sensitive to how much of your slab is within a machine width of a wall.

How to replace it: Ask the contractor how many square feet an hour their machine covers on a slab your size, and how they are handling the perimeter the machine cannot reach.

A8_EDGE_BAND_WIDTH_IN

4.0 inches of perimeter and obstruction edge that no walk-behind machine can reach

The four-inch band around walls, columns and drains that has to be prepared by hand is our own allowance based on typical machine housings.

How to replace it: Measure the housing of the machine you are actually renting. Edge-guard designs vary and some get considerably closer than four inches.

A9_HAND_EDGE_SQFT_PER_HOUR

45.0 square feet per hour of hand edge grinding with a shrouded angle grinder

Hand edging productivity is our own planning figure and is the line item most often left out of a quote entirely.

How to replace it: Time yourself on the first ten feet. Hand edging is slow enough that the first ten feet predict the rest closely.

A10_KIT_GALLONS

3.0 gallons of mixed product in a common two-part kit

Three gallons of mixed material per kit is our default only because two-gallon-resin-plus-one-gallon-hardener is a common packaging; kits are sold in many sizes.

How to replace it: Read the mixed volume off the kit you intend to buy and enter it. Every kit-count figure on this site changes with it.

B1_PROFILE_TARGET_BY_THICKNESS

The mapping from finished film thickness to a required concrete surface profile is our own reading of common practice. The industry reference for surface profile is a paid guideline document we could not retrieve and therefore do not quote.

How to replace it: Your product data sheet states the profile it wants, usually as a CSP number. That sentence beats anything on this page.

B2_FILM_THICKNESS_BY_SERVICE

The film thicknesses this site proposes for each service condition are our own planning bands, chosen so that the resulting material quantities are neither obviously short nor wasteful. They are not a specification.

How to replace it: Ask the manufacturer what total dry film they warrant for your traffic, and use that. A specified system is a build sheet, not a thickness you choose.

B3_COAT_COUNT_BY_SYSTEM

How many separate coats each finish needs is our own model of a normal build, and real systems vary by manufacturer, particularly in whether a separate primer is required over a moisture-mitigating layer.

How to replace it: Take the coat sequence from the build sheet for the product you actually buy, then re-enter the coat count here.

B4_REPAIR_GEOMETRY

Turning a crack length into a repair volume requires assuming a chased cross-section, and turning a spall count into a volume requires assuming an average size. Both assumptions are ours and both are entered by you rather than hidden.

How to replace it: Chase and measure two representative defects before ordering repair material. Cracks widen when you chase them, so a pre-chase measurement always underestimates.

B5_DIY_FEASIBILITY

The judgement about whether an area is realistically within reach of an unassisted person is ours, and it rests on pot life against area rather than on skill.

How to replace it: The only figure that matters is your product pot life at your slab temperature. If you cannot spread a batch before it thickens, the area is too large for the crew you have.

What a coated floor costs per square foot where you live

Asked for on /installed-cost/

This is the number a visitor most wants and the one we are least able to give honestly. The bill is dominated by preparation, and preparation is priced by what has to come off the slab, which nobody can know from a distance. A published national average would read as guidance while being an aggregate of jobs unlike yours. The tool asks for the quotes you have and checks their structure instead.

The volume solids of the product you intend to buy

Asked for on /

Volume solids decides coverage completely, and it varies from around forty percent for a thin water-borne coating to one hundred percent for a true high-build resin. Assuming it would make every gallon figure on the site wrong for most visitors. It is printed on the technical data sheet.

The moisture limit your product publishes

Asked for on /moisture-test/

ASTM F1869 and ASTM F2170 are test methods and publish no pass or fail limit for a coating. The limit belongs to the manufacturer of the specific product and appears on its data sheet. Printing a single industry number here would give a standard-shaped answer that no standard actually contains.

What a grinder or shot blaster rents for near you

Asked for on /surface-prep/

Rental rates for floor preparation equipment move with metropolitan market and with whether diamond tooling is included or billed separately. A national figure would hide the tooling question, which is frequently the larger number.

What labour costs on your job

Asked for on /diy-vs-pro/

We have no defensible source for a floor-coating labour rate that is true in your county, and this site does not publish wage estimates it cannot cite. The comparison instead uses the rate you are actually being charged, or the value you place on your own weekend.

What it costs to dispose of grinding slurry or spent shot

Asked for on /surface-prep/

Disposal is governed locally and wet grinding slurry is treated differently from dry-collected dust in many jurisdictions. Your transfer station or the rental company can tell you; we cannot.