Last Updated on October 6, 2026 by Umar Farooq
The best garage floor coating is the one whose maker publishes a moisture limit for the slab underneath it — because every kit on this shelf is a lid, and the thing that lifts a lid off a garage floor arrives from below.
A coating is the only purchase in this category that can fail completely while being applied perfectly. Mix it right, roll it right, respect every drying time on the box, and a slab still passing water vapour upward will push your new floor off in sheets about six weeks later. The decision was made before you opened the kit, by a measurement almost nobody takes.
So I went and counted who tells you to take it. Twenty phrasings of the query through the Amazon catalogue, fifty-six floor-coating listings at the serious end of the category, and then the manufacturers’ own data sheets. Not one listing names a moisture test. One mentions the word moisture at all, and it recommends the cure without ever mentioning the diagnosis. Then I opened the data sheets and the picture inverted: two of the biggest makers in the category publish the test in plain homeowner language, under a heading that says do not paint. It is simply not on anything you can read before you click buy.
The Slab Vents Upward and the Film Is a Lid
Before the coating, nothing about your slab’s moisture was ever a problem, and that is not because it was dry.
ASTM’s calcium chloride test method puts the baseline in one line of its own Significance and Use section: “All concrete subfloors emit some amount of moisture in vapor form. Concrete moisture emission is a natural process driven by environmental conditions.” Not damp slabs. All of them. A bare garage floor is a slow one-way vent, and the only reason you have never noticed is that whatever leaves evaporates off the top and goes out of the door with the rest of the air.
A film-forming coating is the first thing in that slab’s life that it cannot vent through. The water keeps arriving at the underside, turns to vapour against the back of a cured film, and pushes. ASTM’s in-situ relative humidity method names what happens next without flinching: excessive moisture in floor slabs after a covering has gone down “can cause floor covering system failures such as debonding, peaking and deterioration of finish flooring and coatings and microbial growth.” Debonding is the one you will see — a coin-sized blister in March that is the size of a dinner plate by the time you get round to it.
Where the supply comes from is what makes a garage different from a driveway. A driveway dries from the top because the sky is right there. A slab under a roof, with a car on it and a door shut most of the week, has one escape route and you are about to paint over it. And the variable deciding how much arrives is a sheet of polythene somebody either did or did not lay before the pour, which you cannot see and cannot add now. Simiron, whose epoxy is on this shelf, states the consequence on its own data sheet: “A suitable moisture barrier must be in place for concrete slabs on-grade. If a moisture barrier is not in place, seasonal variations in ground moisture can cause excessive moisture vapor transmission (MVT) regardless of results measured prior to coating application.”
Read that twice, because it is the maker’s own counterweight to everything else on this page. The test can pass in August and the slab can fail in April. That is not a reason to skip the test. It is the reason to run it where the slab is slowest rather than where the light is good.
One thing to settle first. If your slab’s actual complaint is a chalky grey powder that comes back four days after you mop, that is dusting rather than moisture, and the product for it is a chemical densifier rather than anything in this category — that diagnosis, and the water-drop test that separates a sealed floor from a bare one, are both in our guide to cleaning concrete floors. Everything below assumes bare, sound concrete.
A Taped Bag, a Dish of Salt and a Drilled Hole
ASTM maintains three separate ways of answering the question “is this slab too wet to coat”. They are not competing versions of one test. They measure three different things, and they get progressively harder to argue with.
The plastic sheet method, D4263, is the crude one, and the one you will actually run. Its scope is a single sentence: “This practice is used to indicate the presence of capillary moisture in concrete.” Its Significance and Use adds the clause that makes it ours — “Capillary moisture in the concrete may be detrimental to the performance of certain coating systems that cannot tolerate moisture on or within the surface boundary” — and then, flatly, “This practice is designed for use prior to the application of coatings on concrete.” The method itself, and where on the slab to put the square, are covered in our piece on driveway cleaning and sealing. It transfers indoors unchanged.
The calcium chloride method, F1869, gives you a number. A weighed dish of anhydrous calcium chloride under a sealed dome, left on the slab, weighed again: the gain is the water, reported in the standard’s own words as “pounds of moisture over a 1000 ft2 area during a 24-h period.” It is strictly a before test — clause 1.3 says it “shall not be used to evaluate moisture vapor emissions over coatings on concrete or through reactive penetrants” — so there is exactly one moment in your floor’s life when the reading is available, and it is the moment before you commit.
The relative humidity method, F2170, drills into the slab and reads the humidity inside it rather than at the surface, which catches a floor that has dried on top and is still loaded underneath. Its Significance and Use carries the sentence this whole article is built on: “Manufacturers of such systems generally require moisture testing to be performed before installation on concrete.”
Generally require. That is a standards body stating, as background, that asking for the test is normal industry behaviour. Hold that thought for two sections.
All three publish the same limit on themselves, prominently rather than in a footnote. F1869: “The results obtained reflect the condition of the concrete floor surface at the time of testing and may not indicate future conditions.” F2170: “Moisture test results indicate the moisture condition of the slab only at the time of the test and in the specific locations tested.” So the ladder goes present-or-absent, then a rate, then a rate at depth, and not one rung is a guarantee. It is still the difference between a decision made on information and a decision made on how the floor looked on a Saturday morning. (`store.astm.org` is the registry for all three, and the numbers inside the documents sit behind a paywall I have not paid, so everything above is scope and purpose rather than procedure.)
One Listing in Fifty-Six Says the Word Moisture
Here is what twenty phrasings turned up: fifty-six distinct listings at the ticket, from `garage floor epoxy kit` and `polyaspartic garage floor` through `garage floor coating 100 solids` and `hot tire resistant floor coating` to the brand names, which is where the best-documented products were hiding. A pass with no price filter returned zero null prices, so nothing was quietly dropped from the count by a missing figure.
| What the listing publishes | Count, of 56 |
| A moisture test before coating — D4263, F1869 or F2170 | 0 |
| Any mention of moisture in the slab at all | 1 |
| A coverage figure in square feet | 32 |
| No coverage figure of any kind | 24 |
| Two coverage figures against two named surface conditions | 5 |
| A coverage figure against bare concrete specifically | 2 |
| A solids percentage | 18 |
| A solids percentage that is not 100 | 0 |
| A film thickness in mils | 3 |
| A pot life or working time in minutes | 1 |
| A mix ratio | 6 |
| Resistance to hot tyres | 22 |
| A published test behind the hot-tyre claim | 0 |
The one listing is BallistiX, whose BP Resins Single Shot kit carries this in a bullet headed *Read Before Mixing*: “Single Shot can be used as a stand-alone coating, but if moisture is a concern, an MVB base coat is recommended.” MVB is a moisture vapour barrier primer, and this is the only acknowledgement in the category that the slab has an opinion. Five words are doing enormous work there — a concern to whom, established how, at what threshold — and the same listing says the concrete “must be clean, dry, and mechanically profiled”, leaving dry as an adjective. The one product in fifty-six that offers the remedy never tells you how to find out whether you need it, which is a strange shape for a warning to have.
The solids column is the opposite of what I expected. Eighteen listings publish a solids figure, which is better disclosure than this site has found in several hardware categories — and every one of the eighteen publishes the same number. They all say 100% solids. Nobody publishes 70, or 85, or 52. That makes it a chemistry class rather than a measurement: a product either has solvent and water in it or it does not, and the figure tells you which side of that line you are on and nothing about how thick the film will be. Meanwhile the maker whose chemists actually measured it keeps the result on the data sheet — Rust-Oleum’s own sheets publish 96% by volume for one system and 52.6 to 52.8% for another, and twenty-one of the fifty-six listings are Rust-Oleum’s.
Then the hot-tyre row, the most-made claim in the category and the least supported. Twenty-two listings promise resistance to hot tyres or hot tyre peel-up. Not one publishes a test behind it, and the performance tables on the data sheets measure flexibility, hardness, gloss and abrasion — four properties, none of them this one. Simiron puts the real position in writing, in the LIMITATIONS box of its own epoxy sheet: “Tire marking may occur.” That is the product’s own document declining to promise what twenty-two listings promise. The mechanism, and why a more crosslinked film resists it better, belong to removing tire marks from concrete, which also explains why the parking mat that fixes this on bare concrete is the wrong move on a coated one.
Two of the fifty-six are not floor coatings at all, and a search for this category returns them with a straight face: a box of decorative colour flake sold by the pound, and a clear casting resin whose own bullets advertise river tables and jewellery.
Rust-Oleum Publishes the Test Twice and Answers It Two Ways
This is where the absence turns out to be in the listing rather than in the market, and it is the better finding by a distance.
Rust-Oleum’s technical data sheet for its RockSolid polycuramine garage floor coating kit carries a section called *Moisture Testing*, and it reads:
New concrete should be allowed to cure for 30 days before application of any coating. If there is any doubt about the dryness of the concrete, conduct a test by simply taping a piece of 4 mil plastic sheet 18×18″ on the bare concrete for 24 hours. Be sure to tape all four sides. After 24 hours, check the concrete for signs of moisture. The concrete substrate will be darker if damp. If moisture is found, allow additional drying time (10-14 days) and repeat the test.
That is D4263 in homeowner clothing, with a dimension, a thickness of plastic and a dwell time, and the standard is never named. Now the same manufacturer’s sheet for its water-based EpoxyShield garage floor coating, under a heading reading *DO NOT PAINT IF THE FOLLOWING CONDITIONS EXISTS*, where the item is headed Moisture in the Concrete:
Apply a 2′ x 2′ sheet of plastic (such as a heavy-duty garbage bag or 1 gallon plastic storage bag) to an area of the bare concrete garage floor. Tape down the edges with duct tape and allow to set for 24 hours. If water droplets appear on the inside of the plastic or if concrete appears wet (darker in color), moisture is trapped in the concrete and Rust-Oleum Moisture Stop should be used prior to applying a coating.
Same company. Same shelf. Same test, give or take six inches of plastic. Two completely different answers to the same result: one tells you to wait a fortnight and test again, the other tells you to buy a primer. The EpoxyShield sheet goes further in its opening paragraph — the coating “is not intended for use on unsound previous coatings or floors that have a moisture problem.” That is a product excluding your floor from its own scope, printed above the mixing instructions.
So which do you follow. Publish both, and read them as answers to two different causes, because that is what they are. A slab that is wet because it rained last week, or was poured last month, or got washed on Thursday, is a slab that will dry, and the wait is free and the only remedy that removes water rather than trapping it. A slab that is wet because there is no vapour retarder under it will never pass however long you wait, because the supply is the ground — which is precisely the case Simiron calls seasonal and independent of your reading, and the case a barrier primer exists for. Neither sheet tells you which one you have. The plastic test does, if you run it twice a fortnight apart and the second reading is no better than the first.
And none of this is on any of the twenty-one Rust-Oleum listings in the census. Between them they publish ready-for-vehicles times, a seven-day recoat window and the fact that the kit includes a foam roller. The step the maker’s own document files under *do not paint* does not make the bullets.
One Gallon Is 1,604 Square Feet One Mil Thick
A film-forming coating is sold by the square foot and bought for its thickness, and one piece of arithmetic converts between them. A US gallon is 231 cubic inches, so spread one thousandth of an inch thick it covers 231,000 square inches, or 1,604 square feet. A gallon of a 100%-solids coating therefore gives 1,604 square feet at one mil, 160 at ten, 53 at thirty — and because nothing evaporates out of a 100%-solids product, the wet film and the dry film are the same number.
You do not have to take that from me, because one maker publishes the identity. Simiron’s polyaspartic topcoat listing instructs you to “apply at a spread rate of 100 – 160 sq. ft. per gal. to yield 10 – 16 wet film thickness”, and the Simiron 1100SL data sheet prints the same pairing in a table: 160 square feet per gallon at ten wet mils, 53 at thirty. Divide 1,604 by their mils and you get their square feet, to the square foot, both times. This is one of the few places on this site where a conversion survives contact — we have refused the same sum on penetrating sealers, where there is no film plane to be thick and the solids figure does not say whether it is by weight or by volume. On a 100%-solids film-former neither objection applies.
Run it against the listings that give a gallon count and a coverage figure in the same breath, and the category separates:
- Gorilla’s two kits land on the same film. Two gallons over up to 550 square feet is 5.8 mils; one gallon over up to 275 is 5.8 mils. Two kit sizes, one intended thickness. Nothing in either listing says 5.8, but the number is there if you want it.
- ArmorPoxy’s three-gallon clear kit publishes a range that is not a range. “Each 3-gallon kit covers 250-600 sq. ft. depending on floor porosity and application method” is 19 mils at one end and 8 at the other — a factor of 2.4 in the only property the product has.
- Oycevila contradicts itself in its own bullets. It claims 100% solids, “One thick coat up to 15 mils”, and three gallons covering “a full standard 1-car garage (250 sq.ft.)”. Three gallons over 250 square feet is 19.25 mils, not 15. It is the only kit that volunteers a thickness, and its own coverage figure disagrees with it by a quarter.
The water-based case runs the other way and the gap is large. Rust-Oleum’s EpoxyShield sheets publish 52.6 to 52.8% solids by volume, a wet film of 6.0 to 7.0 mils, and a recommended dry film of 3.0 to 3.5 mils per coat. Roughly half of what leaves the roller leaves the floor as well. That is not a defect, since a thin tough film is a legitimate product sold as a one-coat finish — but the gallon that buys nearly six mils of Gorilla buys about three and a quarter of EpoxyShield, and neither listing frames it.
Then the honest limit, which the best-documented product in the census spells out for me. Rust-Oleum’s EpoxyShield Clear Finish kit is 100% solids and publishes two coverage figures: 250 square feet on bare concrete, 500 on painted surfaces. Same kit, same solids, no solvent to lose, so the volume of material is identical and the slab is simply taking half of it into the pores. Its published dry film band is 2.5 to 5.0 mils, which is exactly the 2:1 ratio those two coverage figures describe. A spread rate tells you what to buy. It cannot tell you what you got, because the first part of the pail is filling a texture rather than building a film.
Which is why what is already in the pores matters. Whatever a paint stripper drove into them has to come back out before anything goes on top, an argument made properly in cleaning paint off concrete — and after a salt season, chloride in the surface pores does not leave when the water does.
Once the Pouch Is Burst There Is No Pausing
A two-component coating is the only product in the garage that starts arguing with you the moment you agree to buy it. The clock begins at mixing, it is temperature-dependent, and one listing in fifty-six prints a number for it.
That listing is POURLA’s polyaspartic topcoat, which publishes “a 30-50 minute working time”. Everybody else says nothing or says it in adjectives. Five Spartan Epoxies listings promise “an extended working time, allowing installers greater flexibility and creativity”, which is a sentence about mood. BallistiX gets closest without a figure, and its version is the most alarming: “Do not leave mixed epoxy sitting in the bucket. Mixed epoxy left in mass will harden and cure quickly.”
The data sheets, naturally, have the numbers. Rust-Oleum’s RockSolid sheet gives a pot life of 45 minutes to 1 hour, depending on temperature and humidity, for a coating that ships in a patented burst pouch you mix by rolling it like a tube of toothpaste. There is no lid to put back on. Its LIMITATIONS box adds that “this product must be installed at the specified spread rates to perform as described”, so the clock and the thickness are a single constraint rather than two.
Rust-Oleum’s EpoxyShield sheets do something stranger: a three-row chart that moves the whole schedule with the temperature. At 60 to 70 degrees Fahrenheit you let the mixed coating stand and start rolling 45 minutes after mixing, with a two-hour pot life. At 71 to 80 you start rolling after 15 minutes and have an hour and a half. At 81 to 85 you trim the edges immediately, start rolling somewhere between five and fifteen minutes, and have one hour. Alongside each row the sheet names the time of day, and at the warm end it says “Best time to paint is early morning (before 9 AM) to ensure best curing conditions and maximum pot life.” Note what that first row is, too — a mandatory induction period, forty-five minutes in which the correct action is to stand still, and none of the seven EpoxyShield listings mentions one.
Simiron publishes the fullest version: its 1100SL epoxy comes in three cure speeds with work times of 35 to 40, 20 to 25 and 12 to 17 minutes, footnoted “Higher temperatures will shorten pot-life and working time”, with the instruction “Do not mix more material than can be applied in 10 – 15 minutes (material will stiffen or tack-up)” and the blunter “Do not delay in pouring mixed material onto the floor.” Its polyaspartic topcoat goes further and sells the clock as a grade you choose — fast, medium, slow and extra slow, the slowest offered for “extremely hot and/or humid environments” and for “applicators with less experience.”
The practical consequence is a sum to do at the kitchen table rather than on the floor. Take the bay’s square footage, divide by the kit’s coverage, see how many mixes that is, then check how long each mix lives at the temperature you will actually be working in rather than the one on the chart’s best row. If you cannot cross the floor inside the pot life, the fix is a slower grade or a cooler morning, and both are decisions you make before you buy rather than after you burst a pouch.
What I Would Put on a Slab That Passed
Reviews are by what the maker publishes, because that is the only thing I can check from here. There is no test slab behind this site.
For the best-documented listing in the category: Rust-Oleum EpoxyShield Clear Finish Floor Coating Kit. This is the only listing of fifty-six publishing a solids figure and two coverage figures against two named surface conditions in the same set of bullets — “One kit covers up to 500 sq ft on painted surfaces or 250 sq ft on bare concrete” — and the only one whose published numbers close against each other. A hundred per cent solids, a 2.5 to 5.0 mil dry film band on the sheet, and two coverage rates that are the two ends of that band.
The limitation is in the listing’s own words: “ENCLOSED GARAGES ONLY: Designed for enclosed garage use and not intended for areas exposed to direct sunlight.” That rules out the apron outside the door, a carport and a patio, which is most of where people assume a clear topcoat goes. It is also a topcoat and nothing else — no colour, no flake, no system under it — and its 60-minute pot life appears only on the data sheet.
For a one-coat colour finish where the maker’s document does the moisture work: Rust-Oleum RockSolid Garage Floor Coating Kit. Ninety-six per cent solids by volume, a 45-minute to one-hour pot life, 200 to 250 square feet per pouch, and the only data sheet in the category whose answer to a failed moisture test is to wait and test again rather than to sell you something. The seven-day recoat window without sanding is a genuine convenience on a job that takes a weekend to go wrong.
The limitation is the claim its listing leads with. “RESISTS CHEMICALS AND HOT TIRES” has nothing behind it on the maker’s own performance table, which reports flexibility, hardness, gloss and abrasion and is silent on tyres. The pouch is the other one: once burst it cannot be closed, so the 45 minutes is not a guideline.
For the one maker that publishes a moisture threshold with a number in it: Simiron 1100SL three-gallon kit. Of every document I read for this article, this is the only one that converts “make sure it is dry” into something you can pass or fail: the MVT rate “must not exceed three pounds per 1,000 square feet per 24 hours, as directed by ASTM F1869”, and the slab’s relative humidity “must not exceed 75%, as directed by ASTM F2170”. It also publishes the full work-time table, a 2:1 mix ratio, the 28-day cure minimum on new concrete, and a spread rate tied to a film thickness. That is the complete answer to this article’s question, and it is on a PDF rather than a pail.
Two limitations, and the first is sizeable. The same sheet describes 1100SL as a basecoat “designed to be used over sealed concrete” and recommends installing it over the maker’s own primer “to reduce outgassing on uncoated concrete floors” — so the kit you buy is not the whole system. The second is the LIMITATIONS box quoted earlier: “Tire marking may occur.” Its maintenance section then tells you to place “a small piece of nonporous material, such as sheet metal or plexiglass between the tires and floor to prevent tire marks”, which is a maker agreeing in writing that the film is the thing at risk.
Sold by the Square Foot With No Thickness Attached
Five groups came out of this without a link, and four of them share one failing: each is sold on the film and will not tell you how thick it is.
Gorilla’s two epoxy kits, which came closest to a fourth button. These are the only listings stating a gallon count and a coverage figure in the same bullet — “Covers up to 550 sq. ft.: Includes two gallons of premium material” — which makes the film arithmetic rather than inference, and both kit sizes land on the same 5.8 mils. What stopped the link is that the adjective is still doing the work the number should: the bullet promises “enough for a thick, long-lasting coat”, and the listing publishes no pot life, no mix ratio and no moisture requirement at all. A thicker film is also a bigger lid, so the coating that resists everything else is the one with the most vapour pressure stacked behind it.
Oycevila’s three-gallon clear epoxy kit, which fails its own arithmetic. It publishes “100% Solids”, “One thick coat up to 15 mils” and “This 3-gallon garage floor epoxy kit covers a full standard 1-car garage (250 sq.ft.)”. Those cannot all be true: three gallons of 100% solids over 250 square feet is 19.25 mils. It is the only listing that volunteers a film thickness and the only one whose own coverage figure refutes it. The same bullets assert that “1:1 kits are easy to package, not engineered for strength”, which is a claim about every competitor with nothing behind it.
ArmorPoxy, all fifteen listings. The disclosure here is loud and empty. “10x Stronger Than Steel, Zero Shrinkage: Military-grade 100% solids epoxy” appears on nine of them, and ten times stronger than steel is not a specification — it does not name the property, and the four strength figures Simiron’s sheet publishes for a 100%-solids epoxy all sit between about 9,600 and 12,800 psi, a fraction of structural steel in any of them. I am not pinning those to individual rows, because that table extracts misaligned, but the direction is not close. Add the three-gallon clear kit’s 250 to 600 square feet, which is 8 to 19 mils of film, and no pot life anywhere across fifteen listings.
Rust-Oleum’s seven water-based EpoxyShield garage kits, and this one is close. Credit first: these are the products whose data sheet carries the best moisture instruction in the category, the garbage-bag test under a heading that says do not paint. But the listings are the thinnest numerically. The maker publishes 52.6 to 52.8% solids by volume, a 3.0 to 3.5 mil dry film, a pot life that halves as the day warms up, and a mandatory induction period before the roller touches the floor. None of those four appears on any of the seven listings. On this article’s one criterion that is a fail, and the sheet being excellent is why it stings.
And the two listings that are not coatings. Both are legitimate products in their own aisle, and sending somebody with a bare bay to buy either would be a sale and a mistake at the same time. The flake box in particular looks like part of a system until you read what is in it.
One more thing I would recommend and cannot link you. The item that decides this whole purchase is a roll of clear polythene and a roll of duct tape. It publishes nothing about itself, it does not need to, and it sits a few aisles from the coating. If you want the number instead of the yes-or-no, the calcium chloride kits that run F1869 are sold as singles and as three-packs — three readings across a bay beats one, so the three-pack is the one to want, and it sits below the point where this page links anything. The in-situ sensors that run F2170 are there too, at trade rates, and nobody coating one bay needs a reading per location. Buy the plastic, run the test, then come back for the coating.
FAQ
How do I know if my garage floor is too damp to coat?
Tape a square of clear plastic to the bare slab, seal all four edges, and leave it for a day. Two manufacturers publish exactly that procedure — one specifies 4 mil plastic 18 inches square, the other a two-foot square or a one-gallon freezer bag — and the ASTM practice behind it, D4263, exists specifically “prior to the application of coatings on concrete”. Condensation underneath, or concrete gone visibly darker, is a fail. Put the square where the slab is slowest rather than where it is convenient.
What happens if I coat a slab that is still giving off moisture?
The vapour arrives at the underside of a cured film and has nowhere to go. ASTM’s relative humidity method lists the results as debonding, peaking, deterioration of the finish and microbial growth. In a garage that shows as a blister becoming a flake becoming a bald patch, weeks after the job looked finished, and the only honest repair is to take the coating off and start again.
Does a solids percentage tell me how thick the coating will be?
Only with a coverage rate beside it. A gallon spread one mil thick covers 1,604 square feet, so a 100%-solids product at 550 square feet per two gallons is about 5.8 mils, and a 52.7%-solids product at its maker’s recommended rate is about 3.25. Eighteen of the fifty-six listings publish a solids figure and all eighteen publish 100, which tells you the product has no solvent in it and nothing else. The thickness comes from the division.
Do garage floor coating kits resist hot tyre pickup?
Twenty-two of fifty-six listings say so and none publishes a test for it. The makers’ own performance tables measure hardness, gloss, flexibility and abrasion, and one maker’s limitations box says plainly that tyre marking may occur. A more crosslinked film genuinely resists it better than a loose acrylic does, which is the argument made in full on our tyre marks page, but the marketing promise and the published evidence are not the same size.
How long does a two-part floor coating stay usable after mixing?
Between about 12 minutes and two hours, depending on the chemistry and the temperature, and one listing in the census prints a figure. One maker publishes a pot life of 45 minutes to an hour; another publishes a chart that drops from two hours to one as the floor goes from 65 to 83 degrees Fahrenheit, and tells you to start before nine in the morning at the warm end. Work out how many mixes your bay needs before you open anything.
Do I need to etch or grind the floor first?
Every kit in the census that ships a prep product ships a citric-acid etch, and the makers’ documents are clear that preparation is where adhesion comes from — one specifies grinding to a stated surface profile for bare concrete rather than etching at all. What etching is not is a cleaning step: acid belongs to surface preparation and nowhere else on a slab. Do the cleaning, the degreasing and the water-handling first, which is the whole of cleaning garage floor concrete. And an old oil stain is its own job — a coating bonds to whatever it lands on, and over a chronic drip that is oil rather than cement paste.
The Bag Goes Down a Day Early
Fifty-six listings, nought mentions of a test, and two manufacturers who print the test in their own documents under a heading that says do not paint. The information exists. It has simply never made it onto the page where the money changes hands.
So the order of operations is backwards from how the shelf is arranged. Tape the plastic down on a Friday, on the coldest, darkest, least convenient corner of the bay. Look at it on Saturday. If it comes up dry you have a slab and a weekend, and the only questions left are how thick a film you want and whether you can cross the floor before the bucket goes off. If it comes up beaded, you have learned the one thing none of these kits would have told you, off a bin bag and a roll of tape — and the floor will still be there in a fortnight, when you can ask it again.
