Garage Floor Epoxy in Allen, TX
Garage floor epoxy guides for Allen homeowners: hot tyre pickup, grinding, and realistic project timelines.
When a Garage Floor Coating Has Already Failed
Most writing about garage floor epoxy assumes a bare slab and a clean start. This site assumes the opposite. The floor is already coated, something has gone wrong with it, and the question is what actually happened and what can be salvaged. That is a different problem, and it is answered by looking at the floor in front of you rather than by reading a general list of things that can go wrong.
Reading the Failure Before Deciding Anything
A coating that has lifted is a piece of evidence. Peeling sheets that leave clean grey concrete behind say one thing. Flakes that come away with concrete stuck to the back of them say something completely different, and point at the slab rather than the coating. Small round blisters, tyre shaped patches in front of where the car parks, lifting that starts at the edges: each pattern has a short list of likely causes. The first article covers how to read those patterns, and how a simple tape check and a photograph of the underside of a lifted piece will usually settle the question in ten minutes.
Recoating What Is Already There
Sometimes the existing coating is sound and only the top layer is tired. In that case a recoat is genuinely the right answer, provided the old surface is tested first and then abraded so the new material has something to grip. Sometimes the existing coating is quietly failing across the whole bay, and adding to it buys a year at most. The second article covers how to tell those two situations apart, how spot repairs behave in a flake floor, and why colour and flake matching never comes out invisible.
Repairing the Concrete Underneath
In Allen and the wider North Texas area, the slab damage that shows up under a failed coating is usually surface level: spalling where the top few millimetres have flaked away, pop outs, or a weak troweled layer that never had much strength to begin with. De-icing salt tracked in during the handful of hard winter days each year does its share as well. The third article covers grinding back to sound concrete, choosing between a polymer modified cementitious patch and an epoxy mortar, and how to check a repair has actually bonded before anything is coated over it.
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Reading a Garage Floor That Has Started to Lift
The Failure Pattern Is the Diagnosis
When a coated garage floor starts coming up, the instinct is to work out what product was used or which contractor to blame. Neither answers the question. The pattern of the lifting does. A coating fails in a small number of recognisable ways, and each one leaves a signature you can read without a lab.
Peeling in Sheets With Clean Grey Concrete Underneath
If you lift a loose edge and it comes away in a continuous sheet, and the concrete revealed beneath it is clean, uniform grey with no coating residue stuck to it, the bond never formed properly. The coating cured into a sound film, it just never gripped. That points at preparation: a slab that was sealed or densified and not opened up, a floor that was acid etched and left with residue, oil or transmission fluid soaked into the concrete before coating, or a surface that was still damp when the primer went down. The coating itself is often perfectly good, which is why it peels as one piece rather than crumbling.
Lifting With Concrete Stuck to the Back
Turn a lifted flake over. If there is a thin grey skin of concrete adhered to the underside, the bond to the coating was fine. What failed was the concrete. Slabs poured with too much water at the surface, or over troweled so that fines and cement paste were drawn up into a weak laitance layer, end up with a top millimetre or two that has very little tensile strength. The coating held onto that layer, and that layer let go of everything below it. This is a substrate problem, and no change of coating product will fix it. The weak layer has to be ground off.
Small Round Blisters
Blisters between roughly 5mm and 40mm across, domed and often clustered, are usually either moisture or air. Moisture blisters come from vapour driving up through the slab and collecting under a film that will not let it through, which happens on slabs with no vapour barrier or where a driveway drains back toward the garage. Air blisters, sometimes called outgassing, form when the slab warms during cure and pushes air out of its own pores into the wet coating. If you slice a blister open and the concrete under it is darker or damp, it is moisture. If it is dry, it is air, and it is a cure day problem rather than an ongoing one.
Tyre Shaped Patches and Edge Lifting
Two roughly rectangular patches where the car sits, matching the tyre footprint, are hot tyre pickup. A hot tyre softens some coatings, especially thin single part products, and lifts them when the car cools and the rubber grips. In Allen, where a car can sit on a slab after a run in genuine summer heat, this shows up more often than people expect. Lifting that starts at the perimeter, the garage door threshold or a doorway is usually a termination detail: the coating was not carried into a saw cut or a chased edge, so water and traffic worked at an exposed film edge until it started to peel back.
Two Checks Worth Doing Yourself
- Tape check: press a strip of duct tape or packing tape firmly onto an intact area, then pull it off sharply at an angle. Coating that comes away with the tape is not bonded.
- Cross hatch: score a small grid through the coating to the concrete with a sharp blade, tape over the grid, pull. If squares lift out cleanly, the bond is marginal across that whole area, not just where you can see damage.
Photograph the Underside
Before you throw away a lifted flake, photograph its back in good light next to a ruler. That single image tells you whether you are looking at a bond failure or a concrete failure, how thick the film was, whether a primer coat is visible as a separate layer, and whether there is contamination on the reverse. It is the most useful piece of evidence in the whole diagnosis, and it is the one most people sweep up and bin before anyone qualified sees it.
Repairing Spalled and Damaged Concrete First
What Spalling Actually Is
Spalling is the loss of a slab's surface layer: the top few millimetres flake, chip or sheet away, leaving shallow craters with exposed aggregate. It is a surface condition, not a structural one, which is why a badly spalled garage floor can still be a sound slab underneath. Three causes cover most of it. Freeze thaw, where water in the surface pores expands as it freezes and pushes the top layer apart, which in Allen happens on the handful of hard freezes each winter. De-icing salt, carried in on tyres after a highway trip. And a weak surface from the pour itself: too much water in the mix, or troweling carried on after bleed water appeared, which pulls fines to the top and leaves a skin with little strength.
Pop Outs and Delaminated Laitance
Pop outs are small conical craters, typically 10mm to 50mm across, where a piece of aggregate near the surface absorbed water and blew the concrete above it off. They are localised and cosmetic. Delaminated laitance is more serious: a weak layer sitting on good concrete, still in place but no longer attached. Tap across the floor and listen for a hollow, papery note. It has to come off, because anything coated onto it is bonded to a layer already detached.
Grind Back to Sound Concrete
Every repair starts by removing what is not sound. Grind the damaged area until the tool runs on dense concrete with visible aggregate rather than paste, and keep going past the visible edge of the damage, because the weak zone extends further than the flaking does. Square up the perimeter of a deeper repair, since a patch that tapers to nothing chips under a tyre. Vacuum, and tap again before mixing anything.
Cementitious Patch or Epoxy Mortar
Two families of repair material cover almost every garage floor.
- Polymer modified cementitious patch. Cement based with a polymer added for adhesion and flexibility. It moves with the slab, tolerates a slightly damp substrate, feathers easily and takes a coating well. The right choice for broad shallow spalling and for resurfacing a whole bay.
- Epoxy mortar. Resin loaded with graded sand. Very high compressive and bond strength, cures fast, does not shrink, unaffected by moisture once mixed. The right choice for deep localised holes and for thresholds and edges that take impact. It is stiffer than the slab, so it is not a material to spread over a whole bay.
Depth usually decides. Localised and deep points at epoxy mortar. Wide and shallow points at a cementitious product.
Filling a Low Spot Versus Resurfacing
A low spot where water pools is a different job from spalling. Small depressions can be filled and feathered with a patching compound. Once you are filling more than a few dips, the honest answer is a resurfacer over the whole area, giving one continuous surface rather than a floor made of patches. A coating over many patches telegraphs every one, because each material takes gloss differently.
A Patch Must Be at Least as Strong as the Slab
This is the rule that governs everything above. If the repair is weaker than the concrete around it, the coating fails at the patch first and takes the patch with it. Check the stated compressive and bond strength against a residential slab, commonly around 3000 psi, and choose a product that exceeds it. Follow the mix ratio as stated, not by eye: over watering a cementitious patch is the most common way a good product ends up weak.
Prove the Repair Bonded Before You Coat
Once the patch has cured for the full time specified, tap across it and its edges with a hammer handle. It should ring the same as the surrounding slab, with no change in tone at the boundary. Check the perimeter for a hairline crack tracing the outline of the repair, which means it shrank away rather than bonded. For a firmer answer, glue a steel dolly to the patch and pull it: a break in the concrete below is a pass, a break at the patch to slab line is not. Coating over an unproven repair hides it until the tyre finds it.
Recoating Over a Floor That Already Has Epoxy
The Question Is Not Whether You Can, It Is Whether You Should
Epoxy will stick to epoxy. That part is easy. The real question is whether the coating already on the floor will stay attached to the concrete for the life of whatever you put on top of it. A new topcoat is only as good as the weakest layer beneath it, and adding material to a floor that is quietly letting go means the failure, when it arrives, is thicker and more expensive to remove.
Test What Is There Before You Add to It
Test the existing coating in several places, not one. Take a sharp blade and cross hatch a small grid through the coating to the concrete, tape over it, and pull. Do this at the door threshold, mid bay, where the car parks, and in a back corner that has never seen a tyre. If squares lift out anywhere, treat the whole floor as suspect. Also tap across the floor with a screwdriver handle and listen. A dull, hollow note means the coating and the concrete have separated even though nothing is visibly wrong yet, and hollow areas do not stop spreading because you painted them.
Abrasion Is Not Optional
A cured epoxy topcoat is a closed, glossy surface with almost nothing for a new coat to hold onto. It has to be abraded to give a mechanical key. In practice that means a diamond or silicon carbide screen on a floor machine, or a light pass with a fine resin diamond, taken far enough that the whole surface goes uniformly dull. Any glossy patch left is a future blister. Sanding by hand around edges and door reveals is part of the job, because the perimeter is where recoats start peeling.
Contamination Is the Other Half
A garage floor that has been in use for six or seven years carries residue that abrasion alone will not remove: carbon and plasticiser from tyres, silicone from tyre dressings, degreaser, and whatever household cleaner has been used on it. Silicone in particular causes fisheyes and pinholes at concentrations you cannot see. After grinding, vacuum thoroughly and wipe the floor with a solvent on clean rags, replacing the rag often. One rag dragged across the whole bay redistributes contamination instead of lifting it.
Spot Repairs and the Limits of Matching
If the failure is confined to one area and everything around it tests sound, a patch is reasonable. Cut back to firmly bonded coating with a grinder, then feather the edge so there is no step from old film to new. In a flake floor the flake hides a great deal, which is why flake systems are far more forgiving of a patch than a solid colour floor is. Be realistic about matching, though. The base colour will differ because pigment batches vary and the surrounding floor has aged, and even the same flake blend broadcast by a different hand lands at a different density. A patch in a flake floor is findable if you know where to look. A patch in a plain grey or tan floor is visible to everyone.
When It All Has to Come Off
Full removal is the honest answer when the tape checks fail broadly, when hollow areas are widespread, or when the failure pattern shows concrete coming away on the back of the coating. Removal is done by diamond grinding for smaller garages and by shot blasting where the area justifies bringing the machine in. Both leave a profiled, open surface, which is what the next coating wants anyway. In older Allen neighbourhoods a slab has often been coated once already by a previous owner, and grinding is what finally reveals what is under there.
The Cost of Coating Over a Failing Floor
A recoat over a failing system does not stop the failure. It adds mass and stiffness to a film already losing its grip, so when it releases it comes away in larger pieces and takes longer to remove. The second failure arrives faster than the first, because the original coating had a clean slab to hold and the new one is holding a coating that is already letting go.