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

NIST lists the unit itself as "mil (0.001 in)" in the first column of its table, which is the definition the coverage arithmetic uses. Until 2026-10-05 this row quoted the February 2021 edition of UFGS 09 90 00; the August 2026 edition no longer defines the mil.

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.

The specification states two minimums, 30 days for concrete, stucco and masonry and 90 days for a slab on grade, and gives no reason for the difference. The same sentence appears at the same paragraph in the February 2021 edition first quoted here.

S4_NO_EPOXY_ON_DAMP

1.000 prohibition (no numeric value)

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

This sentence sits in the paragraph for gypsum board, plaster and stucco. For concrete the same specification uses paragraph 3.6.1 d, which keeps the taped-sheet method (ASTM D4263) for vertical surfaces and judges a horizontal surface by a quantified emission test (ASTM F1869).

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

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 for handheld grinders, the tool this site assumes for the edge band a walk-behind machine cannot reach.

S9_VOC_FLOOR_COATING_LIMIT

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

Read from the Floor coatings row of Table 1: 400 grams per liter, and 3.3 in the pounds-per-gallon column. Section 59.410 of the same subpart leaves states and their political subdivisions free to adopt their own limits.

S10_VOC_INDUSTRIAL_MAINTENANCE_LIMIT

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

Section 59.401 defines an industrial maintenance coating as one formulated and recommended for substrates exposed to extreme conditions in an industrial, commercial or institutional setting, and section 59.405(b) requires those products to carry one of four label descriptions: for industrial use only, for professional use only, not for residential use, or a list of the extreme conditions the coating is intended for. The floor-coating definition names flooring, including decks, porches and steps in a residential setting.

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 prints no slip-resistance number: the Access Board guide says the standards set no minimum because no consensus rating method exists.

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

F1869 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

F2170 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

Rounded, this is 1,604. This site keeps the full quotient and rounds once, at the end, because a rounded constant would carry its rounding into each 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 formulated and recommended for decides which row applies. The regulation lets the label show either the product's VOC content or the Table 1 limit it complies with, so a label need not name the row.

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.

A3_CURE_HALVING_DEGF

18.0 degrees Fahrenheit of cooling that roughly doubles cure time

That cure time roughly doubles for each 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: A technical data sheet can publish pot life and recoat windows at a stated temperature, and some publish a second column at a colder one. Where yours does, 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 broadcast to refusal can use several times more, and flake makers 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: A resin manufacturer that sells a quartz system can publish it as a complete build sheet, with the aggregate rate stated per course. Use that sheet where one exists.

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: Ask the rental desk what their machine covers per hour on a slab like yours, and what tooling they are supplying with it.

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 the real rate drops as more of the slab sits 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 for the strip a walk-behind machine housing cannot reach.

How to replace it: Measure the housing of the machine you are actually renting. Edge-guard designs vary, and some reach 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 for a shrouded angle grinder working the edge band.

How to replace it: Time yourself on the first ten feet and scale that to the length of edge band you have.

A10_KIT_GALLONS

3.0 gallons of mixed product in one two-part kit (our default size)

Three gallons of mixed material per kit is our default only so the page shows a worked example; kits are sold in several sizes.

How to replace it: Read the mixed volume off the kit you intend to buy and enter it. The kit count on the takeoff and installed-cost pages changes with it.

B1_PROFILE_TARGET_BY_THICKNESS

The mapping from finished film thickness to a required concrete surface profile (CSP), and the profile each preparation method can reach, are our own planning bands. The industry reference for surface profile is a paid guideline document we have not retrieved and therefore do not quote.

How to replace it: If your product data sheet states the profile it wants, for example as a CSP number, use that instead of 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 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. Chasing widens a crack, so a measurement taken before chasing comes out short.

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 figure to check is your product's 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/

We hold no source for this that we could cite as true for your area. Preparation is a large and variable part of the bill, and it depends on what has to come off the slab, which cannot be judged from a distance. A national average would read as guidance while being an aggregate of jobs unlike yours. The installed-cost tool builds a total from derived quantities and the unit prices you enter instead.

The volume solids of the product you intend to buy

Asked for on /

Volume solids sets coverage directly: at 50 percent solids a gallon covers half the area it covers at 100 percent, for the same dry film. A default would be wrong for any product that differs from it, and the figure is printed on the technical data sheet, so the takeoff asks for yours.

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/

We hold no citable source for rental rates where you live, and whether diamond tooling or shot is included or billed separately changes the comparison. The tool asks for the rate and the tooling cost you are quoted.

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 a jurisdiction can treat wet grinding slurry differently from dry-collected dust. Your transfer station or the rental company can tell you; we cannot.