River Falls, WI · East Twin Cities Metro Mon–Fri 8a–5p · Sat by appt Owner-operated · Veteran-friendly

Surface Prep & Repair · River Falls, WI · Est. 2003

Concrete diamond grinding, crack repair, and surface prep — the real reason coatings last.

The most important step in any floor coating happens before the coating goes down. Surface preparation is the difference between a floor that lasts 15 years and one that peels in 15 months. We use industrial diamond grinding on every install — never acid etch, never shortcut. Diamond grinding is included in every coating job we do. Standalone prep work is also available for contractors and homeowners with damaged slabs that need to be made coating-ready.

Text Dave · (715) 307-8302 See Pricing
100% Diamond grind On every coating install
0 Acid etch Ever, on any job
20+ Years experience Surface prep since 2003
Always Included Not an upsell line item

What we install

Three coating systems for surface prep & repair, all built on polyurea + polyaspartic.

Same diamond-ground prep on every job. Same 15-year written warranty. The difference is the resin chemistry, finish, and price point — picked to match how the floor will be used.

Standard

Included With Every Coating

Diamond grind + crack repair on every garage, basement, patio, or commercial install.

Every floor coating we install starts with full diamond grinding, crack and joint repair, and spalling patch as needed. It's not a line item, not an upsell, not optional — it's the minimum required for a coating that lasts. The reason our 15-year warranty is real is that the prep underneath it is real.
  • Industrial diamond grinding
  • Crack & joint repair
  • Spalling patch + smoothing
  • HEPA-vacuum dust collection

Included in coating price

Sub-Contract

Standalone Prep Service

Damaged slab restoration for someone else's coating.

If another contractor has lined up a coating job and your slab needs serious prep first — old paint removal, deep crack repair, spalling restoration, surface profiling — we'll do the prep work as a standalone service. Diamond grinding only, or full prep including crack repair and patching. Coordinate with the coating contractor on timing and finished surface profile.
  • Diamond grinding only or full prep
  • Coordinate with coating contractor
  • Documented surface profile
  • Per-sq-ft pricing or bid

$2–4 / sq ft

Repair-Only

Repair-Only Service

Concrete crack repair + spalling without a coating.

Cracked or spalled concrete that you want fixed but not coated. Polyurea joint filler for cracks, polymer-modified compound for spalled areas. Restores function and appearance without committing to a full coating. Often a stopgap before a future coating install — when you're ready, the prep is already done.
  • Crack filling (flexible polyurea)
  • Spall + pit repair
  • Joint maintenance
  • Bid based on linear feet + square footage

Bid by scope

Why we don't install epoxy

Why diamond grinding is the only acceptable surface prep — and acid etching is not.

Surface prep is where cheap coating installs get cheap. Acid etching takes 30 minutes with a $40 jug of muriatic acid; diamond grinding takes hours with $30,000 worth of equipment. The cost difference is why some installers acid etch — and the bond difference is why those floors peel. Here's the head-to-head:

Acid Etching What cheap installers do
  • Doesn't open the slab uniformly. Acid reacts with the calcium in concrete unevenly — areas with more cement react more, areas with more aggregate react less. The surface profile after acid is inconsistent.
  • Leaves chemical residue. Muriatic acid leaves chloride ions in the concrete pores. Coatings bonded over chloride residue have a weak chemical bond that fails sooner.
  • Produces a chemical bond, not mechanical. The coating is essentially "glued" to the surface. Mechanical bonds (where the coating fuses into open pores) are dramatically stronger.
  • Doesn't remove existing coatings. Old paint, sealers, or coatings have to come off some other way. Acid won't dissolve them. Many installers acid-etch over partial old coatings — guaranteed failure.
  • Health + environmental concerns. Strong acid in residential garages and basements is unpleasant. The runoff has to go somewhere. Local code is increasingly restrictive on residential acid use.
Diamond Grinding What we use
  • Uniform surface profile. Diamond-tooled grinders cut the same depth across the entire slab regardless of cement-to-aggregate ratio. The surface profile after grinding meets ICRI CSP-3 to CSP-4 standards for coating bond.
  • Removes contamination + weak top layer. Grinding cuts through the laitance (the weak, dust-prone top layer of cured concrete) and any surface contamination — oil, paint, sealers, coatings — in one pass. Clean substrate for the bond.
  • Mechanical bond. The coating fuses into the open concrete pores, locking in. Mechanical bonds resist 4-10× the pull-off force of chemical bonds in published lab tests.
  • Removes any existing coating. Old paint, epoxy, or sealer comes off cleanly. We grind down to bare concrete on every job.
  • HEPA-vacuum dust collection. Industrial grinders with attached HEPA vacuums make zero dust mess in residential interiors. Garage, basement, mudroom — we can grind without making the rest of the house unlivable.

If a coating contractor offers to "save you money on prep" by acid-etching, that's the moment to walk away. The prep is the foundation of the install — saving 30 minutes on prep guarantees a re-install in 18 months. Diamond grinding is the only surface prep we do, and it's included in every coating price.

Crack repair: flexible filler, not rigid patch.

Cracks in concrete come from slab movement — settlement, freeze-thaw expansion, or original control-joint design. The crack will keep moving for the life of the slab. We fill cracks with flexible polyurea joint filler that bonds to both sides of the crack and stretches with the movement. Rigid patch compounds (which is what most contractors use) crack along the same line within 1-2 winters because they don't accommodate movement. Polyurea filler doesn't.

Spalling repair: rebuilding the surface, not coating over it.

Spalling is when chunks of the concrete surface flake off, exposing aggregate or creating shallow craters. It's caused by salt damage, freeze-thaw, or original concrete that didn't hydrate properly. Coating over spalling without repair means the coating will conform to the craters and look terrible. We rebuild the surface with polymer-modified concrete repair compound first — it bonds to the existing concrete, hardens overnight, and creates a smooth substrate for the coating to go down on.

Old sealers, paint, and previous coatings.

Most older slabs have something on them — concrete sealer (from when the slab was new), garage paint (someone's DIY attempt), or a failed previous coating. All of it has to come off before a new coating can bond. Diamond grinding removes most of it cleanly in a single pass. Stubborn cases (heavy oil contamination, deeply penetrating sealers) get an extra grind pass or a chemical degrease before grinding. By the time the new coating goes down, the slab is bare concrete substrate.

Moisture testing for below-grade slabs.

Basement and below-grade slabs transmit ground moisture upward continuously. Before coating any below-grade surface, we run an MVER (moisture vapor emission rate) test — a calcium-chloride disc that measures water vapor coming up through the concrete over 60-72 hours. Readings under ~3 lbs / 1000 sq ft / 24 hr clear for a standard install. Higher readings get a moisture-mitigation primer first. Either way you know what your slab needs before the coating goes down.

Transparent Pricing

Surface prep pricing: included free with every coating, or $2–4 / sq ft standalone.

For a coating install, prep is included in the per-sq-ft coating price — never a separate line item, never an upsell. For standalone prep work (sub-contracting to another coating contractor or repair-only jobs), pricing depends on slab condition + scope.

With Coating Install

Included

any coating job

From $0 to extra
  • Diamond grinding
  • Crack & joint repair
  • Spalling patch as needed
  • Built into coating price
Get my number
Sub-Contract Prep

Standalone

any sq ft

From $2 to $4 / sq ft
  • Diamond grinding only or full prep
  • Coordinate with coating contractor
  • Documented surface profile
  • Larger jobs price lower per sq ft
Get my number
Repair-Only

Bid by scope

linear ft + sq ft

From Quote to by Dave
  • Crack filling (per linear foot)
  • Spall + pit repair (per sq ft)
  • No coating
  • Stopgap before future install
Get my number

Standalone prep is typically a contractor-to-contractor arrangement, but homeowners with damaged slabs sometimes commission repair-only work as a stopgap before a future coating install. Send photos + scope and Dave will quote.

The 6-step install

How we install your surface prep & repair, step by step.

Same checklist on every floor. The reason our coatings still look new at year ten when the cheap stuff peeled in year two.

  1. 01

    Assess slab condition

    On-site visit to evaluate slab condition: existing coatings, cracks, spalling, oil contamination, moisture indicators. Determines scope of prep work needed and which grind tooling to use (concrete hardness varies, tooling matches).
  2. 02

    Diamond grinding (full slab)

    Industrial diamond-tooled grinders, HEPA-vacuum dust collection, ICRI CSP-3 to CSP-4 surface profile. Wall-to-wall, edge-to-edge, including corners and tight spots. Removes existing coatings, contamination, and the weak laitance layer.
  3. 03

    Crack & joint repair

    Visible cracks filled with flexible polyurea joint filler that moves with the slab. Control joints either filled flush (smooth surface) or maintained as visible (homeowner preference). Edge cracks at the slab perimeter sealed.
  4. 04

    Spalling + pitting repair

    Spalled surface areas patched with polymer-modified concrete repair compound, troweled flat to match surrounding surface. Pits filled and smoothed. Compound cures overnight, ready for coating the next day.
  5. 05

    Surface clean + final inspection

    Full vacuum sweep + tack-cloth wipe to remove residual dust before coating goes down. Walk-through with homeowner to confirm prep is complete and sign off before basecoat.
  6. 06

    Documented + warrantied

    For standalone prep work, we document surface profile (CSP rating) and crack repair scope so the coating contractor has a record. For our own coating installs, the prep is integrated into the 15-year coating warranty — bond failure due to inadequate prep is on us, not you.

Common Questions

Common questions about surface prep & repair.

Why does my floor coating keep peeling?
Almost always inadequate surface prep. The most common cause is acid etching instead of diamond grinding — the chemical bond is dramatically weaker and fails first under thermal cycling, moisture, or load. Other causes: coating applied over old coating without grinding it off, moisture transmission from below (untested), or hot-tire pickup damage on epoxy. If a previous floor coating peeled within a few years, the next one needs to be installed differently — start with full diamond grinding to remove whatever's left, then a polyurea (not epoxy) system on top.
What's the difference between diamond grinding and acid etching?
Diamond grinding mechanically cuts the concrete surface with diamond-tooled abrasives, opening the pores uniformly and creating a mechanical bond profile (ICRI CSP-3 to CSP-4). Acid etching uses muriatic acid to chemically react with the surface — uneven, leaves chloride residue in the pores, creates a weaker chemical bond. Lab pull-off tests show diamond-ground surfaces hold coatings at 4-10× the bond strength of acid-etched surfaces. We never acid etch.
Is surface prep included in the coating price?
Yes — diamond grinding, crack repair, and spalling patch are included in every coating install we do. It's not a separate line item or upsell. The 15-year warranty exists because the prep underneath it is right; charging extra for prep would be charging extra for the foundation of the install.
Do you do standalone surface prep without a coating?
Yes — for two cases: (1) sub-contracting to another coating contractor whose own crew doesn't have grinder equipment, and (2) repair-only work for homeowners with cracks or spalling that need fixing but who aren't ready for a full coating yet. Standalone prep runs $2-4 per square foot depending on slab condition and scope; repair-only is bid by scope.
How long does the diamond grinding take?
For a typical 2-car garage (~440 sq ft), grinding runs 2-3 hours including setup, wall-to-wall coverage, and cleanup. Larger spaces scale linearly. Crack repair adds 30-60 minutes depending on linear footage. Spalling repair adds 1-2 hours per 100 sq ft of repair area. The dust is contained by HEPA vacuum so the rest of your house stays livable during grinding.
Will the dust from grinding be a problem?
No — our grinders run with attached HEPA-vacuum dust collection. Effectively zero airborne dust escapes during grinding. We can grind in residential garages, basements, and mudrooms without affecting other parts of the house. After grinding we vacuum the slab a final time before any coating goes down.
What if my slab has cracks — can it still be coated?
Almost always yes. Cracks get filled with flexible polyurea joint filler before the coating goes down. The filler bonds to both sides of the crack and stretches with future movement, so the crack doesn't telegraph back through the coating. Exceptions: structural cracks (deep, through-slab, or growing) are signs of a foundation issue that should be addressed before coating. We'll tell you on-site.
What about old paint or sealer on the floor?
Diamond grinding removes most old paint, sealers, and coatings cleanly in one pass. Stubborn cases (heavy enamel paint, deeply penetrating sealers) get an extra grind pass or a chemical degrease step before grinding. By the time the new coating goes down, the slab is bare concrete substrate.
Do you handle severely spalled or damaged concrete?
Most spalling, pitting, and minor surface damage is repairable with polymer-modified concrete compound, troweled flat, and overcoated. Severely damaged concrete (large sections lifted from frost heave, structural cracks, deep through-slab damage) is sometimes beyond restoration — a coating over a structurally bad slab buys 1-2 years before the underlying problem reappears. We'll tell you straight if your slab needs replacement instead of restoration.
Why do you test for moisture before coating below-grade?
Below-grade slabs (basements, walk-outs, lower-level garages) transmit ground moisture upward through the concrete. High moisture causes coating delamination — the bond between coating and slab fails as moisture vapor builds up underneath. We run an MVER test before coating any below-grade surface; readings tell us whether the slab is dry enough for a standard install or needs a moisture-mitigation primer underneath. Avoids the most common cause of below-grade coating failure.

Where we work

Surface Prep & Repair across western Wisconsin and the east Twin Cities.

We do surface prep across western Wisconsin (River Falls, Hudson, Eau Claire, Menomonie) and the east Twin Cities metro (Woodbury, Stillwater, Hastings, Cottage Grove). Most prep work is part of our own coating installs; standalone sub-contract prep is available for coating contractors in the area whose own crews don't have grinder equipment.

Talk to Dave

Got a damaged slab that needs prep before coating?

Send Dave four photos of the slab and a description of what's wrong. We'll tell you whether it's restorable and what the prep scope looks like — same-day text response. For our own coating installs, prep is always included.

(715) 307-8302 Text Dave · Fastest reply
  • Free on-site measurement
  • Written 15-year warranty
  • No subcontractors, no upsells
FREE QUOTE

Tell Dave about your slab.

By submitting you agree to be contacted about your project. We don't sell your info, ever.

Text Dave (fastest) Call