Concrete Floor Repair & Prep for Epoxy Coatings | Knoxville TN

Crack chasing, spall patching, pitting fill, joint repair, and full diamond-grind surface preparation — the unglamorous work that determines whether your new epoxy or polyaspartic floor still looks good five years from now. Most coating failures we see across East Tennessee trace back to skipped or cheaped-out prep, not bad product.

What this service is — and what it isn’t

We do cosmetic and coating-prep concrete repair: the surface-level work needed to turn a damaged garage, shop, or basement floor into a sound substrate for an epoxy or polyaspartic coating. That covers cracks, spalls, pop-outs, pitting, joint damage, and surface roughness — the 90 percent of concrete damage that actually walks through our quote process.

We do not do structural concrete work. If your slab is sinking, you have a foundation crack from settling, you need a driveway leveled, or a section of floor needs to be poured fresh, that’s a different trade and we’ll tell you so on the site walk. We can refer you to a structural concrete or mudjacking contractor in East Tennessee who handles that work. There’s nothing more wasteful than coating over an unresolved structural problem — the coating will telegraph every movement of the slab underneath and fail in months.

The page below covers what we actually fix, what it costs, and the diamond-grind prep we run on every coating job regardless of how good the concrete looks.

Damage types we repair before coating

These are the conditions we run into most often on Knoxville garage and shop floors, in rough order of frequency:

Hairline and narrow cracks (under 1/8 inch)

The most common condition in residential garages — thin shrinkage cracks that have been there since the slab cured. We chase each crack with a diamond crack-chaser blade to open it to a uniform width (about 1/4 inch), then fill with a polyurea joint filler. The filler cures rubbery, flexes with slab movement, and the coating bridges over it cleanly. Done right, these cracks vanish under the finished floor and don’t telegraph back through.

Wider cracks and active cracks (1/8 to 1/2 inch)

Wider cracks get the same treatment — chase, clean, fill with polyurea — but we also check whether the crack is “active” (still moving with seasonal temperature changes) by comparing width at the slab edges to width at the middle. Active cracks get a slightly more flexible filler and sometimes a fiberglass reinforcing mesh tape under the coating in that zone. Cracks over a half inch wide with vertical displacement (one side higher than the other) usually indicate structural movement and get flagged for a different contractor.

Spalling, pop-outs, and surface flaking

Spalling is where the top quarter to half inch of concrete is flaking off in patches — usually caused by salt damage, freeze-thaw cycles, or a poor original pour. East Tennessee garages see a lot of this from road salt tracked in over winters. We grind the spalled area back to sound concrete, apply a bonding primer, and patch with a fiber-reinforced polymer cement mortar. The patch cures in 24 hours and gets ground flush before coating.

Pitting and surface roughness

Pitted floors with small craters and pop-outs across the surface are repaired with a thickened epoxy mortar troweled into the pits and scraped flush. For floors with heavy pitting across more than 20 percent of the area, we skim-coat the whole slab with a self-leveling polymer cement before grinding — costs more but produces a noticeably flatter finished floor.

Failed control joints and saw cuts

Most garage slabs in East Tennessee have intentional saw-cut control joints to direct where the concrete cracks as it cures. By 15 to 20 years in, those joints often spall along the edges or fill with debris. We clean them out with a joint-cleaning blade, re-square the edges, and fill with polyurea — same product as the crack fill. The coating runs continuously across the filled joint, but the joint is still doing its job underneath.

Oil stains, paint overspray, and old coatings

Surface contamination doesn’t structurally damage the slab but it does prevent a coating from bonding. Oil stains get treated with a degreaser plus mechanical scrubbing; deeper oil penetration gets ground out completely. Old paint and prior failed coatings are removed by shot-blasting or aggressive grinding — there’s no shortcut and no coating that “bonds through” a failing paint layer.

What we won’t coat (honest scope)

Some conditions can’t be solved by surface repair and we’ll tell you so on the walk:

Sinking or settling slabs. If sections of your floor are visibly lower than others, the slab needs to be lifted (mudjacking or polyurethane foam) before any coating goes on. We’ll refer you to a Knoxville-area concrete lifting contractor.
Active foundation cracks. A crack that runs from a wall into the floor and is still moving is a structural issue, not a flatwork issue. Same referral.
Slabs with unresolved moisture intrusion from below. If groundwater is wicking up through the slab (visible as efflorescence, dark damp patches, or repeated moisture-meter spikes), no coating will hold long-term until the moisture source is addressed.
Concrete poured within the last 28 days. New concrete is still curing and gases out moisture. Anything coated before full cure delaminates inside the first year.

We’d rather walk away from a job than coat a floor that’s going to fail. Refusing the wrong jobs is part of why the coatings we do install last.

Diamond-grind surface preparation

Every coating job we do starts with diamond grinding the entire floor, not just the damaged areas. This is the single most important step in the process and the one most often cheaped out by lower-end installers.

What diamond grinding does: a counter-rotating grinder fitted with diamond-segment tooling removes the laitance (the weak, dust-prone top layer of cured concrete), opens up the surface porosity, and creates a controlled mechanical profile that the coating physically anchors into. The industry-standard target profile for epoxy is CSP-2 to CSP-3 (Concrete Surface Profile per the International Concrete Repair Institute), roughly equivalent to the texture of 60- to 80-grit sandpaper.

Why we don’t acid etch: acid etching with muriatic acid is the budget shortcut competitors use. It creates a profile of CSP-1 at best, doesn’t remove surface contamination, leaves chloride residue that interferes with adhesion, and produces a waste stream that’s not safe to send down a storm drain. A coating over acid-etched concrete typically fails 3 to 5 years sooner than the same coating over a diamond-ground floor.

Dust extraction: we run HEPA-rated vacuum systems on every grinder. Diamond grinding without dust extraction fills a garage with silica dust at OSHA-actionable levels and coats every surface in white powder. Customer-friendly grinding means HEPA extraction at the grinder, period.

Moisture testing after grind: we run calcium chloride or relative humidity probes on slabs at risk for vapor transmission — most basements, any slab-on-grade in a humid East Tennessee summer, and any garage we don’t already have history on. Slabs above 5 pounds per 1,000 square feet per 24 hours get a vapor-mitigating primer before the coating goes down. Coating a wet slab is the second-most-common cause of failure after skipping the diamond grind.

What concrete repair and prep cost in Knoxville

Installed pricing for Knoxville and East Tennessee, separated out so you can see what the prep portion of a quote is actually costing:

Hairline and narrow crack repair (polyurea fill, chased): $3 to $6 per linear foot of crack
Wider crack repair with reinforcing: $6 to $12 per linear foot
Spalling and pop-out patching: $4 to $10 per square foot of damaged area
Pitting fill (epoxy mortar): $2 to $5 per square foot of pitted area
Full skim-coat for heavily pitted floors: $3 to $6 per square foot of total floor
Failed control joint cleanup and refill: $4 to $8 per linear foot
Diamond grinding (standard prep, included in every coating job): $1.50 to $3 per square foot — about 25 to 35 percent of the total installed coating price
Vapor-mitigating primer (when moisture test fails): $1.25 to $2.50 per square foot of treated area
Removal of failed existing coating before new install: $1.50 to $3.50 per square foot depending on coating thickness

On a typical 2-car Knoxville garage (about 450 square feet) with a handful of hairline cracks, a few small pop-outs, and one failed control joint, repair work usually lands in the $300 to $600 range on top of the coating price. Heavily damaged shop floors with widespread spalling and pitting can run $1,500 to $3,000 in repair before any coating goes down.

Why prep is what makes the coating last

When we see a 3-year-old failed epoxy floor in Knoxville, it’s almost never the product’s fault. Modern 100% solids epoxy and polyaspartic resins from real manufacturers (Penntek, Citadel, Elite Crete, ArmorPoxy, Roll-On Rock) are mature, well-tested chemistry — they don’t spontaneously fail. What fails is the bond between the resin and the concrete underneath. And that bond is determined by prep.

The three most common failure modes we replace, in order:

Coating delaminated in sheets. Almost always means the original installer acid-etched instead of diamond grinding, or didn’t remove a prior coating fully. The new coating bonded to the old coating instead of to the concrete, and the whole stack lifted together.
Coating bubbled or blistered after 6 to 18 months. Moisture transmission from below. The installer skipped moisture testing or skipped the vapor-mitigating primer.
Coating peeled along cracks and control joints. Joints and cracks weren’t properly filled with polyurea before coating, so the coating stretched and split as the slab moved seasonally.

All three failures cost more to remediate (rip-out plus reinstall) than a properly prepped job would have cost the first time. This is why we don’t cut corners on prep, and why the coatings we install carry their full manufacturer-backed warranties.

Our process

On-site walk. We come out, look at the concrete, photograph the damage, run a quick moisture-meter check, and ask about the floor’s history (when it was poured, prior coatings, water issues). Free, no obligation.
Written scope and quote. Repair work, prep work, and the coating system are itemized separately so you can see what each line costs. If we think the floor needs structural work first, we say so and refer you out.
Day 1, morning: repair. Crack chasing, spall patching, pitting fill, joint repair. Most residential garages get all repair work done in 2 to 4 hours.
Day 1, afternoon: cure window. Polyurea fillers cure in 30 to 60 minutes; epoxy mortar in 4 to 6 hours; cement-based patches in 24 hours.
Day 1 or Day 2: diamond grind. Full-floor grind to CSP-2 to CSP-3 profile with HEPA dust extraction. Moisture testing on at-risk slabs.
Coating install. Per the system spec in your written quote — see our garage floor epoxy, polyaspartic, metallic, or commercial & industrial pages for the system that fits your floor.

Get a concrete repair and prep quote in Knoxville → (865) 459-3144

Frequently asked questions

Can damaged concrete be coated, or does the slab need to be replaced first?

The honest answer: most damaged garage and shop floors in Knoxville can be coated successfully after repair — replacement is rare and usually unnecessary. What matters is the type of damage. Surface cracks, spalling, pop-outs, pitting, and minor unevenness all repair fine and disappear under the coating. Wider structural cracks (over a quarter inch with vertical displacement), slabs that are visibly sinking, or concrete with active moisture intrusion from below need to be addressed differently — sometimes by a structural concrete contractor before we even quote a coating. We tell you which category your floor is in during the on-site walk, not after we've sold you a job.

Can you coat over cracked concrete, or do you have to pour new concrete first?

We coat over cracked concrete routinely — pouring fresh concrete is almost never the right answer for a typical residential or commercial coating project. What we do instead: we chase the cracks with a saw or grinder, fill them with semi-rigid polyurea joint filler (the same product used in commercial warehouses), let it cure, then grind everything flush. The repair becomes a structural part of the slab and disappears under the coating. Fresh concrete actually creates a worse coating substrate than properly repaired old concrete because new concrete takes 28+ days to cure enough for coating, has higher moisture content during that window, and laitance (the weak surface layer) has to be removed anyway.

How much does it cost to repair cracks in a Knoxville garage floor before epoxy?

For residential garage floors in Knoxville, crack and spall repair runs about $0.75 to $2.50 per square foot of floor area on top of the coating price, depending on how much of the floor needs work. A typical 2-car garage with a handful of hairline cracks and a couple of small pop-outs is usually in the $300 to $600 range for repair work. A garage with deep cracking across most of the slab, significant pitting, and failed control joints can run $1,200 to $2,000. We quote the repair line-item separately from the coating so you can see what the prep is actually costing rather than burying it.

How do you repair spalling concrete?

Spalling — where the top quarter to half inch of concrete is flaking off in patches — is fixed by removing all the loose material first, grinding the spalled area back to sound concrete, applying a bonding agent, and patching with a polymer-modified concrete repair mortar. For shallow spall (under a quarter inch deep), we use a thin-set polymer cement; for deeper spall we use a fiber-reinforced repair mortar. After the patch cures (usually 24 hours), the entire floor gets diamond ground to a uniform profile so the repair vanishes under the coating. The key step most homeowners miss is the bonding agent — patching without one creates a repair that pops off within a year or two.

How do you repair pitted concrete in a garage floor?

Pitting — small craters, pop-outs, and surface holes in the concrete — is repaired with a self-leveling polymer-modified cement or with a thickened epoxy mortar applied with a flat trowel. For garage floors that will be coated, we usually use a thickened epoxy mortar because it cures faster (4 to 6 hours vs. 24+ for cement) and bonds chemically with the epoxy coating that goes on top. The mortar is troweled into the pits, scraped flush, allowed to cure, and then the whole floor is diamond ground. For severely pitted floors (more than 20 percent of the surface area), we sometimes use a full skim-coat instead of spot-filling — it costs more but produces a flatter finished floor.

What does floor prep cost on its own, separate from the coating?

For Knoxville residential garages, diamond grinding alone is typically priced at $1.50 to $3.00 per square foot if you bought just the prep service — but we generally don't sell prep separately, because grinding without a coating that goes on within 24 to 48 hours leaves bare ground concrete that immediately starts soaking up oil, water, and dust. When prep is included in a full coating quote, it's effectively rolled into the per-square-foot installed price you see for the coating. We list it as a separate line item on the written quote so you can see exactly what the prep portion costs — typically about 25 to 35 percent of the total installed coating price.

Areas we serve

We provide concrete floor repair and surface prep across Knoxville including West Knoxville, Farragut, Bearden, Sequoyah Hills, Fountain City, Powell, plus nearby Maryville, Oak Ridge, Alcoa, Lenoir City and surrounding East Tennessee. See our full service area →

Last updated: May 19, 2026

Concrete Floor Repair & Prep for Epoxy Coatings in Knoxville, TN