Epoxy coating vs garage floor paint

Behr, KILZ and Rust-Oleum all sell one-can garage floor paint with "epoxy" in the name. Their own data sheets list the resin as acrylic/epoxy or modified acrylic, at about 32% to 36% solids by volume. Solids are the part that stays on the floor once the water and solvents evaporate.^{[1- to 3]}

Rust-Oleum's own buying guide says garage floor paint is typically an acrylic paint, sometimes called a one-part coating, and that a 2-part epoxy coating gives greater protection.^[28]

Porch and floor enamel is a different product again. Sherwin-Williams, PPG and California Paints each say not to use their porch and floor paint where cars drive or park. California Paints gives the reason: hot tires or the weight of a vehicle can make it lose adhesion.^{[29- to 31]}

A true epoxy has two parts, a resin and a hardener. Once mixed, they react and harden into a solid coating. Paint dries as its water evaporates. A 100% solids epoxy cures by that chemical reaction instead.^{[4, 32]}

Many DIY 2-part kits are water-based. Rust-Oleum's EPOXYShield kit is about 53% solids and H&C Shield-Crete about 41%. The water leaves as the coat dries, so the film shrinks. Sherwin-Williams gives the example of a 7 mil wet coat drying to about 3 to 3.5 mils.^{[6, 11, 32]}

Professional base coats such as Simiron's 1100SL are 100% solids. With no water or solvent to leave, what goes down wet stays on the floor. The 1100SL goes on at 10 to 30 mils per coat.^{[12, 32]}

It is also harder to handle. Simiron says to mix no more than you can apply in 10 to 15 minutes, and Sika labels its epoxy for professional use only by experienced applicators. Rust-Oleum's water-based kit must be used within 1 to 2 hours of mixing, and H&C lists a pot life of 5.5 hours at 77°F.^{[6, 11, 12, 16]}

Rust-Oleum's RockSolid kit sits in between. Its data sheet lists a blend of epoxy, urethane and polyurea at 96% solids. It is still a DIY product, and each mixing pouch covers up to 200 to 250 sq ft.^[13]

The word "Professional" on a box does not make it a pro system. Rust-Oleum's solvent-based EPOXYShield Professional coating is about 69% to 72% solids and goes on at 3.5 to 5 mils per coat.^[33]

A mil is one thousandth of an inch. Here is how thick each option goes on, from the makers' data sheets.

• Garage floor paint: about 1.0 to 1.6 dry mils per coat (Behr and KILZ). Rust-Oleum's 1-part EPOXYShield paint sheet lists 3.0 to 3.5, though its own wet thickness and solids work out to about 2 to 2.5 by our arithmetic.^{[1- to 3]}
• Water-based 2-part kit: about 3.0 to 3.5 dry mils in one coat (EPOXYShield).^[6]
• Solvent-based kit: 3.5 to 5 mils per coat (EPOXYShield Professional).^[33]
• Pro epoxy base coat: about 8 to 12 mils, with a primer under it and a topcoat over the chips (Simiron SimFlake SB).^[5]
• Finished pro flake floor: about 60 mils nominal (Simiron) or 1/16 inch, about 62 mils (Sherwin-Williams), including the chip layer.^{[5, 7]}

So paint and a water-based kit both stay thin, a few mils a coat. The big jump in thickness comes with a 100% solids pro system.^{[1- to 3, 5, 6]}

Chips tell the same story. Rust-Oleum's 1 lb bag of decorative chips for its DIY coatings covers 125 to 250 sq ft. Pro systems broadcast chips over the whole wet floor at about 5 to 7 sq ft per lb. By our arithmetic, that is roughly 18 to 50 times more chip per square foot.^{[5, 17, 34]}

Hot tire pickup is when a coating stains, marks or lifts where warm tires sit. Sherwin-Williams describes two causes. Plasticizers move out of the rubber into the coating and stain it. Heat from quick stops and starts can also soften the coating and mark it for good.^[35]

Paint makers say their 1-part paints resist hot tire pickup. The same Behr data sheet says an annual touch-up may be needed in areas with tire traffic, and the label says cardboard can go under tires after 72 hours if needed.^{[1, 14, 15]}

DIY kit pages go further, with lines like "No hot tire pick-up" and "Stops hot-tire pickup". None of the data sheets we read names a test behind these claims, so treat them as marketing, not measurements.^{[6, 11, 18, 19]}

Pro epoxy is not immune either. Simiron's 100% solids epoxy sheet says tire marking may occur and suggests sheet metal or plexiglass under parked tires. Its flake system guide, which uses a polyaspartic topcoat, carries the same warning. Westcoat recommends a polyaspartic topcoat where tire staining is a concern. Polyaspartic is a fast-curing coating related to polyurea, with good UV stability. Elite Crete also notes that some urethane topcoats resist hot tire pickup better than epoxy.^{[4, 5, 12, 20]}

Whatever you choose, wait the full time the label gives before you park on it. The waits are listed under "How long before you can park on it" below.

We found no source that puts a percentage on how many failures come from prep, so we won't give one. Manufacturers and the concrete repair standards body do agree that prep decides the result. Sherwin-Williams calls it "an extremely important factor", Rust-Oleum's kit sheet says "Preparation is critical to performance", and Diamond Vogel calls it the most difficult part of coating a floor.^{[6, 36- to 38]}

Paint and kits use a chemical etch. Behr's label calls for an etcher such as muriatic acid until the floor feels like 150 grit sandpaper. Rust-Oleum's EPOXYShield kit comes with a mild citric etch and says not to use muriatic acid. H&C allows an etch but says grinding gives the best performance.^{[6, 11, 15]}

Professional systems are ground with diamond tooling or shot blasted. Simiron, Sika and Elite Crete call for mechanical prep to a concrete surface profile (CSP) of about 3 or more. CSP is the industry's roughness scale, from CSP 1 (least rough) to CSP 10 (roughest).^{[12, 16, 17, 38]}

Why pros moved away from acid: Sherwin-Williams says it cannot remove curing compounds or oily deposits, can leave a residue that blocks bonding, and adds water to the slab. It also says acid etching tends to leave a CSP 1 to 2 profile, while today's thicker systems need CSP 3 or more. ICRI's chart puts acid etching at CSP 1 to 3 and plain grinding at CSP 1 to 2, so the grinding has to be aggressive, or the slab shot blasted, to reach CSP 3.^{[38- to 40]}

Garages add their own problem. H&C warns that tires leave chemicals in the driving lanes, which may show as dark brown stains, that can stop a coating from bonding.^[11]

Three checks you can do yourself

• Water drop test. Drip water on bare concrete. If it beads, a sealer is there and has to come off. Sherwin-Williams says by diamond grinding, shot blasting or another mechanical method.^{[6, 36]}
• Tape test on old paint. Cut an X through the coating with a razor, press duct tape over it and pull it off fast. Rust-Oleum says not to coat if more than 25% comes off. RockSolid's limit is 10%.^{[6, 13]}
• Plastic sheet test. Tape a 2 ft by 2 ft sheet of plastic to the floor for 24 hours and look for droplets or darker concrete. ASTM treats this as an indicator only, and Sherwin-Williams says it only tells you whether more testing is needed.^{[6, 36, 41]}

Pro systems set measured moisture limits. A calcium chloride test (ASTM F1869) must typically show no more than 3 lb per 1,000 sq ft per 24 hours. An in-slab humidity probe (ASTM F2170) must read 75% to 85% or lower, depending on the product. ASTM notes a reading only describes the slab at that time and place, and Simiron warns that slabs with no vapor barrier can go over the limit later with the seasons.^{[12, 16, 36, 42]}

If water pushes up through the slab, paint is not the fix either. Behr and KILZ both say not to use their paint on areas subject to hydrostatic pressure.^{[1, 2]}

The steps vary by product, but the system guides we read follow this order.^{[5, 17]}

1. Moisture testing, with measured tests on slabs on grade.^{[12, 36]}
2. Diamond grinding or shot blasting to about CSP 3. This also takes off sealers and old non-epoxy coatings.^{[5, 12, 36]}
3. Cracks and holes filled with an epoxy filler and scraped flush.^{[5, 21]}
4. Joints designed to move are honored rather than buried under the coating, or they can show through the floor.^[12]
5. A thin epoxy primer.^[5]
6. A 100% solids base coat tinted to match the chips, spread with a notched squeegee and back-rolled at about 8 to 12 mils.^[5]
7. Chips tossed up so they fall evenly into the wet base, until the whole floor looks dry.^{[5, 17]}
8. Once cured, loose chips removed, the floor scraped, and vacuumed again.^{[5, 17]}
9. A clear topcoat. Simiron's system uses a polyaspartic topcoat, and urethane is another option over epoxy.^{[4, 5]}

The Indiana painter says its garage floor jobs typically take three to four days because of cure times between coats.^[21]

• Garage floor paint: 7 days (Behr, KILZ, Rust-Oleum EPOXYShield 1-part) or 5 days (Rust-Oleum Concrete and Garage Floor Paint). Behr and KILZ also say to wait 30 days before washing the floor.^{[1- to 3, 14]}
• Water-based 2-part kit: 3 days (EPOXYShield). H&C lists heavy traffic at 72 hours and full cure at 7 days.^{[6, 11]}
• RockSolid: 24 to 36 hours, depending on temperature and humidity.^[13]
• Pro 100% solids epoxy: Simiron lists heavy traffic at 2 days and full cure at 5 days. Sika lists light traffic at about 2 days and full cure at about 7 days at 68°F. Your installer's product sheet decides.^{[12, 16]}

These times assume mild weather. Rust-Oleum says to allow more time when it is cooler.^[6]

These are prices that retailers and installers publish on their own sites, read on the day we checked. We left out lead-generation sites and market averages. Prices change and vary by region, so use them as a starting point.

Doing it yourself (materials)

• Paint: one retailer listed Rust-Oleum Concrete & Garage Floor Paint & Primer at $57.99 a gallon, with 400 sq ft of coverage. That is about 15 cents a square foot per coat, by our arithmetic.^[8]
• 2-part kit: another retailer listed Rust-Oleum's EPOXYShield 2.5-car kit at $189.88, covering 450 to 500 sq ft. That is about 38 to 42 cents a square foot for one coat, by our arithmetic. The etch and decorative chips are in the box. The listing suggests a separate clear topcoat for best results, which costs extra.^[23]
• Budget too for degreaser, rollers, tape and, if you follow one installer's DIY advice, a grinder rental.^{[6, 43]}

Hiring it out

• Painted floor: The Indiana Painting Company lists prices from $1.50 a sq ft for an emptied garage, about $1,250 for a two-car garage. That covers a scrubber clean, cracks filled with caulk and two coats of epoxy paint, guaranteed for 2 years against coming loose. Chips and a clear coat add from about $1 a sq ft. Grinding is part of its pricier system below.^[21]
• Painted floor: Klappenberger & Son, a Maryland painter, prices epoxy paint at about 50 cents a sq ft per coat for labor and materials, on a two-coat job. It adds about $300 to $450 to clean a two-car garage and $300 to etch it.^[22]
• Ground and fully coated by a painter: the same Indiana company grinds off old coatings, fills cracks, and applies a primer, two coats of a 2-part urethane and a clear topcoat. It lists $4.50 a sq ft, about $3,400 for a two-car garage, with a 5-year warranty against coming loose.^[21]
• Pro flake floor, Dallas area: Dallas Epoxy Guys list flake systems at $5.50 to $7.00 a sq ft, with a $2,500 minimum for home jobs up to 400 sq ft.^[9]
• Pro epoxy, Toronto: GLI Epoxy Flooring says its two-car jobs of about 400 sq ft typically run $2,400 to $4,800 all in. The page does not state a currency or whether tax is included.^[10]

The gap pays for grinding, crack repair, several coats and a full chip layer. Dallas Epoxy Guys put it simply: kits cost less because they usually use thinner materials, limited prep and fewer layers, and they last less.^{[5, 9, 21]}

No data sheet we read gives a lifespan in years. Paint makers tell you to expect touch-ups. Sherwin-Williams says older water-based coatings suit lighter duty with more frequent recoating, and that good 100% solids epoxy over prepared concrete can last many years. Westcoat, which makes pro epoxy systems, suggests recoating the topcoat at about 5 years, depending on use.^{[1, 3, 20, 32]}

Installers do give numbers, and they don't all agree.

• Paint: The Indiana Painting Company guarantees its painted floors for 2 years against coming loose.^[21]
• DIY kits: Polished Floors, a Toronto installer, puts a water-based kit at 2 to 5 years. GLI says box-store kits start to peel within 1 to 3 years under car traffic.^{[10, 24]}
• Pro epoxy: Polished Floors gives 5 to 10 years for single-coat epoxy and 10 to 15 for a multi-coat flake system, with a fresh topcoat every 3 to 5 years. GLI says 7 to 12 years in a GTA garage.^{[24, 25]}
• The outlier: Southern Woods, which does not install epoxy, puts professional epoxy at 2 to 5 years in its cost guide and at 5 to 10 years on another page.^{[26, 27]}

Each installer is describing its own climate, its own products and the systems it sells. Southern Woods does not install epoxy, and GLI says most Ontario installers recommend polyaspartic by default. Use the ranges as a rough guide, not a promise.^{[25, 26]}

Read warranties closely. Simiron and Sika each warrant their material for one year and exclude labor, so a long floor warranty comes from the installer, not the resin maker. Ask what yours covers and for how long.^{[12, 16]}

• Light use. A storage room, workshop or garage you rarely park in. Cipkar Epoxy, an Ontario installer, says paint may be okay for a light-use storage room but is usually not the best choice for a busy garage.^[44]
• Outdoor slabs. Behr rates its 1-part paint for driveways, porches and pool decks. Rust-Oleum and H&C say their water-based epoxy kits are for indoor use only, and epoxy discolors in sunlight.^{[1, 11, 16, 18]}
• Easy upkeep. Paint goes over sound paint after you remove loose paint and scuff sand. Simiron's pro epoxy system calls for grinding off coatings that are not epoxy based first.^{[12, 45]}
• A tight budget or a short stay. A gallon of paint costs a small fraction of a pro floor.^{[8, 9]}

Skip paint if you park every day and want years without touch-ups, if water pushes up through the slab, or for heavy-duty use. KILZ labels its paint for residential use only.^{[1, 2]}

DIY kits have a place too. A kit costs far less than a pro job, and it is a true 2-part epoxy, though a water-based kit is not much thicker than paint. If you go that way, Precision Epoxy Flooring, an Ohio installer, suggests renting a real grinder, buying 100% solids material from a coatings supplier and planning a separate topcoat.^{[3, 6, 9, 23, 43]}

• Read the data sheet. A one-can product with acrylic in its resin type is paint. A pro epoxy base coat such as Simiron's 1100SL lists 100% solids. High solids alone don't make it pro: RockSolid, a DIY kit, is 96%.^{[1, 2, 12, 13]}
• Ask about prep. If the plan is an acid or citric etch, it is a kit-level job. Pro systems are ground or shot blasted to about CSP 3.^{[5, 6, 15, 17]}
• Count the layers. A kit is usually one rolled coat with scattered chips. A pro flake floor has a primer, base coat, full chip broadcast and clear topcoat.^{[5, 6]}
• Look at the chips. Rust-Oleum's DIY chips are decorative and spread thin, at 125 to 250 sq ft per pound. A pro broadcast covers the whole wet floor at about 5 to 7 sq ft per pound.^{[17, 34]}
• Ask how moisture is tested. A pro should measure it with ASTM F1869 or F2170, not only tape down plastic.^{[12, 36, 41]}
• Ignore the words on the box. "Professional" and "epoxy" don't tell you thickness or prep. Rust-Oleum's EPOXYShield Professional goes on at 3.5 to 5 mils per coat.^[33]
• Ask who backs the warranty. Simiron's and Sika's material warranties run one year and exclude labor, so the installer's warranty is the one that matters.^{[12, 16]}

Do the tape test first. If the old paint fails, it has to come off before anything new goes on. Precision Epoxy Flooring, Southern Woods and Dallas Epoxy Guys all say peeling coating must be removed first. Southern Woods puts it plainly: new coating over peeling coating will just peel again.^{[6, 9, 27, 43]}

Paint over sound paint is simple: Behr says to remove loose paint and scuff sand. A pro epoxy system needs more. Simiron calls for grinding with 30 grit metal diamonds to fully remove topcoats that are not epoxy based.^{[12, 45]}