Spec notes · 2026-09-30

Two garage floor epoxy quotes that don't match, compared line by line

You measured the garage once, called two installers, and got two written numbers back that look like they were priced for different houses. Same slab in Cape or Jackson, same two cars, same flake color on the sample chip. Our cost page gives the short version of what to do about it: “Compare quotes line by line: surface prep method, solids content of the epoxy, film thickness in mils, and what the top coat is.” This is the longer version, from your side of the kitchen table with both estimates in front of you.

Why do two epoxy quotes for the same garage come in so far apart?

Usually because they are pricing two different jobs. A garage floor epoxy quote bundles prep, repairs, a moisture answer, the base coat, the flake and the top coat into one number, and two installers can leave different pieces out. The widest gap nearly always lives in the prep line.

So before comparing totals, lay the two estimates side by side and look for the same words on each. Where one quote names a step and the other is silent, you have probably found the difference. Circle those spots on both pages. The sections below take the lines in roughly the order most estimates list them.

What prep is each quote actually pricing?

Three words show up on garage floor quotes around here, and they promise very different amounts of work. “Grind” means a diamond grinder cuts the top skin off the slab so the primer has sound concrete to bite into. “Etch” means an acid wash that roughens the surface without removing the old sealer, oil, or chalky top layer an older slab carries. “Clean” or “degrease” on its own means the floor gets washed and the coating goes on over whatever was there.

A quote that says only “surface prep” has told you nothing. Ask which of the three it is. If the answer is etch or clean, the lower number makes sense, and you are comparing a two-day job against a one-day job. Why the grind is worth paying for on an older Cape slab is its own article, and the prep walk-through covers grinding versus acid etching step by step.

Does the quote include a moisture reading?

Look for a number. A quote written after someone metered the slab will either show the reading or name the primer the reading called for. A quote with no mention of moisture was written without knowing, and on a river-valley slab that can sit over wet Southeast Missouri clay, not knowing is the most expensive gap two estimates can have.

A floor coated over high vapor drive blisters from underneath. A high reading changes one thing on a garage estimate. The standard primer gets swapped for a vapor-mitigation primer that goes down first and holds the moisture under it, and that line adds cost. If one quote carries it and the other does not, ask whether the second installer tested at all. Basements run into this more often than garages, and how a damp basement slab changes the system is covered on the basement page.

What do 100% solids and a mil number on a quote tell you?

“100% solids” means everything rolled onto the floor stays on the floor. Lower-solids products carry water or solvent that evaporates as they cure, so the film you end up with is thinner than the coat that went down. Two quotes can list the same number of coats and leave very different floors behind if one product is 100% solids and the other never says.

Thickness is where quotes get slippery. Epoxy floor thickness is measured in mils, thousandths of an inch, and a quote can state it two ways. A per-coat number tells you what each layer builds. A total number tells you what the finished floor measures from concrete to clear. A quote showing only a single per-coat figure for the base can look thinner than a quote showing the total, when the finished floors would measure about the same. Ask each installer for the same thing, the total film thickness of the finished system, and compare those.

Our garage page lays out the full layer stack we build, base coat thickness included, so you have one complete example to hold the other quote against. If one of your numbers came in close to kit pricing, the DIY kit comparison shows what thin film does on a garage floor in a Missouri summer.

Which top coat is on each quote, and why does it matter at the door line?

Find the last layer on each estimate. A polyaspartic or other aliphatic top coat stays clear in sunlight. An epoxy clear coat ambers where UV hits it, and in a garage that means the strip inside the overhead door where the afternoon sun lands every time the door is up.

That band also takes the hottest tires, straight off Kingshighway or I-55 in July. Two quotes that match on every other line can split here, because polyaspartic costs more per coat. If a quote only says “clear coat,” ask which chemistry. The polyaspartic floor coating page explains what that top layer does and why we put it on garage floors.

Which repairs are in the number, and which get priced on the day?

A quote only covers the repairs someone saw. Most garages here have a crack or two, some spalling along the door line where road salt and freeze-thaw have popped the top skin, and pitting in the tire paths. An installer who walked the slab and wrote those down can price them into the estimate. An installer who quoted from square footage over the phone cannot, so those repairs turn up on the morning of the job as a change order.

Read each quote for the word repair and for what it covers. Our published ranges already include standard crack and spall repair, because the measure happens before the number is written. Heavier damage is a separate line, and so is an old coating that has to come off first, and a failed kit takes longer to grind away than bare concrete does. If a previous coating is peeling, the repair article sorts out whether it can be recoated or has to be removed, and either answer belongs on the quote before you sign it, not after the grinder is in the driveway.

What should a full-flake two-car garage quote land at around Cape Girardeau?

Our published range for full-flake epoxy under a polyaspartic top coat is $6 to $9 per square foot, which puts a 400 square foot two-car garage at $2,400 to $3,600. That range already assumes the slab gets ground and the usual cracks and spalls get fixed. A quote well under it is usually missing a line from the sections above. One well over it should name the reason somewhere on the page.

Three things push an honest quote past the top of that range. The one-day full polyaspartic system runs $3,000 to $4,400 on the same garage, because every coat in it is the pricier material. Heavy slab repair or removing an old coating adds prep hours. A high moisture reading adds the mitigation primer. Each of those should appear on the page by name, and the full table by system shows what a two-car garage floor costs here across solid color, flake, metallic and one-day systems.