A complete polyurea + polyaspartic system runs 15-25 mils thick total (basecoat + flake + topcoat). That's about 10x thicker than a DIY kit (1-3 mils) and 2-3x thicker than many cheap contractor jobs. Thickness matters for wear life, chemical resistance, and the ability of the coating to absorb impact and abrasion without wearing through to concrete.
But thicker isn't automatically better. Here's what the 15-25 mil number actually means and why our system hits that range.
What does "mil" mean?
A mil is one one-thousandth of an inch (0.001"). It's the standard unit for coating thickness. For reference:
- A sheet of printer paper: about 4 mils
- A credit card: about 30 mils
- Latex paint: 1-2 mils dry
- DIY epoxy kit: 1-3 mils
- Thin contractor epoxy: 4-8 mils
- Our Valence system: 15-25 mils
So we're about the thickness of a credit card, applied as a continuous layer over the whole floor. That's substantial — it has real presence under your hand, not paint-thin. You can actually see the depth if you look at an edge where the coating meets unfinished concrete.
Why 15-25 mils and not thicker?
Diminishing returns. Once you get past about 25 mils on a residential garage floor, you're adding cost and cure time without adding meaningful performance. The system hits its full bond strength, flexibility, and abrasion resistance at 15-25 mils. Going to 40 or 50 mils is overkill for residential use and actually introduces problems — thicker films can trap moisture, cure unevenly, or crack internally.
Industrial flooring for forklifts and heavy equipment can run thicker, 60-125 mils, because the impact and abrasion loads are dramatically higher. For a car, a truck, tools, and foot traffic, 15-25 mils is the right number. It's the sweet spot where performance, cost, and cure time all line up.
Why are DIY kits so thin?
They're priced for the box store. A kit that covers a 400 sqft garage at $300 has to be thin — there's not enough material in the bucket to apply a thick coat. Manufacturers know this, and they rely on the homeowner's expectation of a "paint-on" application.
The problem is that 1-3 mils of coating doesn't have enough material to survive normal wear. Tire traffic abrades through in a few years. Salt and moisture penetrate the thin film. Impact from dropped tools chips it. There's no reserve. I wrote more on this in why DIY epoxy failed.
How is 15-25 mils built up?
It's not one thick coat — it's layers. Here's the breakdown on a typical install:
- Polyurea basecoat: 8-12 mils. Rolled on over freshly ground, profiled concrete. This layer does the bonding and provides flexibility.
- Flake broadcast: variable. We throw colored vinyl flakes into the wet basecoat at 100% coverage. The flakes embed and build surface texture. Excess flakes are swept and vacuumed the next morning.
- Polyaspartic topcoat: 6-10 mils. Rolled over the cured, vacuumed flake layer. Seals the flakes in and provides UV, chemical, and abrasion resistance.
The thickness varies across the floor by a few mils depending on substrate profile, application rate, and flake density. 15-25 mils is a realistic range for typical installs.
Does thickness affect warranty?
Yes. The 15-year residential warranty assumes a system applied at rated film thickness with proper prep. Contractors who cut mil thickness to save material are outside the manufacturer's spec and have weaker warranty support if problems come up. I apply at spec or above, every job. It's not worth saving a half-gallon of material to risk the warranty and the install lifespan.
How do you measure it?
Wet film gauges during application and dry film gauges after cure. The wet film gauge is a little toothed blade we press into the wet coating to read depth. Dry film gauges use magnetic or eddy-current readings. For residential work I'm mostly measuring wet film during application to hit my spec — at our pricing I'm not going to shortchange material.
On commercial jobs with a written coating spec, dry film readings go on a report. Commercial work often requires documented film thickness.
Does thicker look different than thinner?
Yes, subtly. A thicker film has more depth to the finish — you can see "into" the flakes a bit more, and the gloss has more richness. A thin film looks flatter and the flakes look like they're stuck to the surface rather than embedded in it. Once you've seen them side by side, you can tell, though most homeowners wouldn't notice without a direct comparison.
More importantly, thicker feels different under the hand. Run your fingers across a 20-mil polyaspartic surface versus a 3-mil DIY kit — the thick one is smooth and solid, the thin one feels like painted concrete. The thick one also sounds different under foot — there's a slight dampening quality instead of the clap of thin paint on bare concrete.
What about the flake — does it add thickness?
A little. The flakes themselves are 1/4" vinyl chips, but they embed mostly into the basecoat and get covered by the topcoat. The effective added thickness from flake is maybe 2-4 mils on top of the basecoat once the excess is vacuumed off.
The bigger role the flake plays is surface texture, visual color, and hiding cracks or imperfections. More on color selection in choosing flake colors.
How does our thickness compare to competitors?
Most real contractor installs in the Twin Cities / western Wisconsin market run 10-15 mils on the low end and 20-30 mils on the high end. Ours is toward the top of that range. The cheap jobs you see advertised at $3-4 per square foot are usually 6-10 mils with skimpy prep — those are the ones that fail in 2-3 years and are why people get sour on floor coatings.
I cover what you should be asking contractors about this and more in questions before hiring a floor coating installer.
Is thicker always better?
No — better chemistry at the right thickness beats more thickness with bad chemistry. A 20-mil polyurea system outperforms a 40-mil epoxy system because the chemistry flexes, bonds, and wears better. I'd rather have 20 mils of Valence Covalent Flake than 50 mils of box-store epoxy any day.
Thickness is one metric, but it only means something when paired with the right product, right prep, and right installer. Ask any contractor about all three before you sign a contract.
Will the thickness feel different on my feet or under tires?
Subtly. You'll feel a hint of give — not softness exactly, but the coating isn't rock-rigid like bare concrete. It's easier on your back if you stand at a workbench for hours, and tires roll across it with a slightly different sound than bare concrete. Most people find the change comfortable. Nothing about it feels soft or spongy; it's just a little less harsh than raw slab.
Want to see how a real 15-25 mil system looks and feels? Check the gallery for recent installs, or get a free quote or call Dave at (715) 307-8302.