Epoxy floors bubble and blister because gas or moisture trapped under the coating pushes up through a film that is already starting to cure. That gas comes from three places: water vapour rising out of the concrete slab, air escaping the concrete as it warms, or solvent and air whipped into the resin during mixing. Fix the source before the coating goes down and the bubbles never form.
We have poured and repaired epoxy across Richmond for years, and the same three culprits show up on almost every bubbled floor we inspect - from Steveston garages to warehouse slabs near the Fraser. Below we break down each cause, how to spot it, and what it takes to fix it properly in 2026.
What actually causes epoxy to bubble and blister
Epoxy bubbling is a coating failure where trapped gas or water vapour lifts the cured film off the concrete, creating a raised dome that eventually cracks or peels. It is not a cosmetic quirk and it does not heal on its own.
Three conditions drive almost every case:
- Moisture vapour rising through an unsealed or damp slab.
- Outgassing - air and gas escaping concrete as it warms under the coating.
- Application error - too-thick pours, poor mixing, or coating a slab that is too hot or too cold.
Richmond sits on a lot of low-lying ground with a high water table, so moisture-related bubbles are more common here than in drier parts of BC. If your floor was poured in a home built before the 1990s, there is a good chance the slab has no vapour barrier under it at all.
Why does epoxy bubble on garage floors in Richmond?
Garage floors bubble more than any other surface because they combine the two worst conditions: a slab sitting directly on damp ground, and a surface that swings in temperature every time a car pulls in or the door opens.
A typical Richmond garage slab sits 100 to 150 mm above soil with no vapour barrier on older builds. When the ground is saturated - which is most of the fall and winter here - water vapour pushes up through the concrete at a steady rate. If the epoxy is not moisture-tolerant, that vapour collects under the film and lifts it into blisters within weeks.
Add a warm car parked on a cold floor and you get the second problem: the slab heats up, air inside the concrete expands, and it has nowhere to go but up through the coating. This is why we see the worst bubbling in the tire-track zones and near the garage door where temperature shifts hardest.
For most Richmond homes, the fix starts with proper Garage Floor Epoxy Coating in Richmond, British Columbia (BC) built on a moisture-tolerant primer and a slab that has been tested, not guessed at.
Moisture vapour: the number one culprit on the West Coast
Moisture vapour transmission, or MVT, is the rate at which water vapour moves up through a concrete slab. In Richmond it is the single biggest reason epoxy fails.
We test every slab before we quote a coating. The standard test is a calcium chloride kit or an in-situ relative humidity probe. Anything above 3 lbs/1000 sq ft/24 hr of vapour transmission, or above 75% internal slab humidity, means you need a moisture-mitigating primer before any epoxy goes down.
Signs your slab has a moisture problem:
- White, chalky powder on the concrete (efflorescence).
- Dark patches that never fully dry after rain.
- Existing paint or sealer peeling in sheets.
- A musty smell in the garage or basement, even in summer.
If you skip the test and coat anyway, the epoxy will blister from the bottom up. We have pulled up coatings that looked perfect for eight months and then lifted across an entire 400 sq ft garage in a single wet season.
Outgassing and the concrete that was never sealed
Outgassing is air and gas escaping from concrete as it warms or as the epoxy soaks in. It is different from moisture, but the result looks the same - small pinholes and blisters across the surface.
New concrete is the worst offender. Slabs poured within the last 28 days still hold a lot of free moisture and air. Even older slabs outgas when the surface is porous and has never been sealed.
The fix is straightforward: fill the pores before you coat. We use a thin primer coat rolled in and back-rolled so it soaks into the concrete and seals the surface. On very porous slabs we apply two primer coats and let the first one cure fully before the second.
Temperature matters here too. Coating a slab above 30°C accelerates cure so fast that trapped air cannot escape before the film skins over. Coating below 10°C slows the cure and lets moisture pool under the film. The sweet spot for most epoxy systems is 15°C to 25°C slab temperature, which is why we schedule most Richmond installs in late spring and early fall.
Application mistakes that trap air under the coating
Even with a dry, well-prepped slab, a sloppy application will still bubble. The most common mistakes we see:
- Mixing too fast with a drill paddle. High-speed mixing whips air into the resin. That air has to go somewhere, and it goes up through the film as bubbles.
- Pouring too thick. Most epoxy systems have a maximum wet-film thickness per coat - usually 250 to 400 microns. Go thicker and the cure generates heat faster than the film can release gas.
- Rolling in direct sun or on a hot slab. The surface skins over in minutes, trapping everything underneath.
- Skipping the primer. Bare concrete wicks resin out of the first coat, leaving pinholes that become blisters.
- Not back-rolling. A roller alone leaves a thin, uneven film. Back-rolling with a spiked roller releases trapped air and evens the coat.
Every one of these is avoidable with a proper Concrete Floor Preparation in Richmond, British Columbia (BC) routine and a crew that has done it hundreds of times.
How to fix blistered epoxy without tearing out the whole floor
Small blisters - under 25 mm across and isolated to a few spots - can be repaired without recoating the whole floor. Here is the process we use:
- Grind out the blister down to bare concrete with a diamond cup wheel.
- Feather the edges of the surrounding coating so the repair sits flush.
- Test the exposed concrete for moisture. If it reads high, the whole floor is at risk and a patch will not hold.
- Prime the repair area with the same primer used on the original job.
- Re-coat and blend with the surrounding colour and topcoat.
If more than about 20% of the floor is blistered, or if blisters keep coming back after a patch, the whole coating has to come off. That means Epoxy Floor Removal in Richmond, British Columbia (BC) with a walk-behind grinder or shot blaster, followed by a fresh install on a properly tested slab.
Typical 2026 pricing in the Lower Mainland for a full garage strip-and-recoat runs $4.50 to $8.00 per square foot depending on the system and how much prep the slab needs. A spot repair is usually $300 to $800. Basement and commercial jobs price higher because of access and equipment.
Common mistakes we see on Richmond epoxy jobs
Most of the bubbled floors we are called to fix were installed by someone who skipped a step. The pattern is consistent:
- No moisture test. The single biggest cause of failure on Richmond slabs.
- Acid etching instead of grinding. Etching leaves a profile that looks fine but does not open the pores enough for a proper mechanical bond.
- Big-box DIY kits. Water-based epoxies sold at retail are thin, low-solids products that fail fast on a damp slab.
- Coating over a sealed or painted floor. The new epoxy bonds to the old coating, not the concrete, and lifts as soon as moisture builds.
- Ignoring slab temperature. Coating at 8°C in November because the schedule said so.
If you are planning a floor for a home or business in the area, working with a crew that does this every day is cheaper than fixing it twice. Our Epoxy Flooring in Richmond, British Columbia (BC) service starts with a slab test and a written scope, so you know exactly what you are getting before the first drum is opened.
When to call a professional
Call a pro if the blisters cover more than a small patch, if they came back after a repair, or if you have never had the slab moisture-tested. Those three signals mean the problem is in the concrete, not the coating, and no amount of patching will hold.
We also get called when a homeowner is about to coat a garage or basement for the first time and wants it done right. Our team at Richmond Elite Epoxy Flooring tests every slab, preps it properly, and installs a system rated for the moisture levels we actually see in Richmond. If you are weighing a DIY kit against a professional install, we are happy to walk you through the numbers.
Frequently Asked Questions
Can I fix epoxy bubbles myself?
Yes, if there are only a handful of small blisters under 25 mm. Grind them out, prime the bare concrete, and re-coat. If more than 20% of the floor is affected, or if the blisters return within a few months, the slab has a moisture problem and needs a full strip and re-coat.
How long does it take for epoxy to bubble after application?
Most bubbling shows up within 24 to 72 hours as the coating cures, especially on warm days. Moisture-driven blisters can appear weeks or months later, often after the first heavy rain or a seasonal temperature swing. If blisters show up months in, moisture is almost always the cause.
Does humidity in Richmond make epoxy bubbling worse?
Yes. Richmond averages 70% to 80% relative humidity through fall and winter, and the water table is high in low-lying areas like Steveston and East Richmond. That combination pushes more vapour through unsealed slabs, which is why a moisture-mitigating primer is standard on our installs here.
Will a topcoat stop epoxy from bubbling?
No. A topcoat sits above the epoxy and does nothing to stop vapour rising from below. The fix has to happen at the slab - either a moisture-tolerant primer or a full vapour barrier. A Clear Epoxy Topcoat in Richmond, British Columbia (BC) protects the surface from wear and UV, not from moisture underneath.
How much does it cost to fix a bubbled epoxy floor in Richmond?
Spot repairs run $300 to $800 in 2026. A full strip and re-coat on a standard two-car garage is $4.50 to $8.00 per square foot, so roughly $2,000 to $4,000. Basement and commercial jobs price higher because of access, equipment, and downtime.
Get help with Epoxy Flooring in Richmond
If your epoxy floor is bubbling, blistering, or peeling, we can tell you in one visit whether it is a patch job or a full re-coat. We test the slab, show you the numbers, and quote the fix upfront.
Call Richmond Elite Epoxy Flooring at +7742316666 to book a slab inspection and get a straight answer on what your floor needs.