Why Epoxy Floors Bubble and How To Fix Them
There's nothing quite like the sleek, polished look of a new garage floor. It transforms a utilitarian space into a clean, professional-looking extension of your home. However, that satisfaction can quickly turn to frustration if you notice bubbles, blisters, or pinholes appearing on the surface.
This phenomenon, known as epoxy floor bubbling, is a common issue with traditional epoxy coatings, especially in Edmonton's climate. At Garage Floors 4 Less Edmonton, we believe in empowering homeowners with knowledge. Understanding why epoxy floors bubble is the first step toward a permanent solution.
The Primary Culprit: Moisture and Outgassing
The most common cause of bubbles in an epoxy floor is a process known as "outgassing." Concrete is a porous material, meaning it contains tiny air pockets and can hold moisture. When a thick, non-breathable layer of traditional epoxy is applied, changes in temperature and humidity can cause the air and moisture trapped within the concrete to expand and migrate to the surface. This escaping gas exerts pressure beneath the coating, causing bubbles, craters, or pinholes, which are exacerbated by Edmonton’s changing seasonal humidity.
Our climate puts stress on concrete slabs due to temperature fluctuations and moisture movement. If a garage floor isn't properly prepared and sealed, this moisture vapor transmission becomes a major problem for standard epoxy, which can turn brittle and fail, leading to widespread bubbling and peeling.

In Edmonton, seasonal freeze-thaw cycles are particularly aggressive, and even garages with controlled indoor temperatures can experience moisture migration from the surrounding soil. Homeowners often overlook that condensation from furnace vents or water heaters can cause epoxy bubbling, making a thorough assessment before application critical.
| Common Cause | Description | Prevention/Solution |
|---|---|---|
| Outgassing | Air and moisture escaping from the porous concrete slab, pushing up the coating | Proper surface preparation, using a moisture-mitigating primer |
| High Humidity | Applying epoxy in humid conditions or on a damp slab can cause a chemical reaction that leads to bubbles | Thorough moisture testing and ensuring the slab is completely dry before application |
| Porous Concrete | The concrete absorbs the primer unevenly, leaving areas for air to escape | Applying multiple coats of a high-quality, penetrating primer to fully seal the slab |
| Improper Mixing | Mixing the epoxy resin and hardener too quickly can introduce air into the mixture, which then gets trapped during application | Slow, controlled mixing at a low RPM to ensure a smooth, air-free consistency |
How To Fix Bubbling Epoxy Floors
Fixing a bubbling epoxy floor can be a challenging process. For small, isolated bubbles, the solution might involve sanding down the affected area, patching it, and reapplying the topcoat. However, this often results in a visible patch that doesn't quite match the rest of the floor. If the bubbling is widespread, which is common when the issue is related to moisture or improper preparation, the only real solution is to mechanically grind the entire coating off and start from scratch. This is a labour-intensive and costly undertaking.

This is why professional preparation is non-negotiable. Before any coating is applied, the concrete must be thoroughly profiled, typically through diamond grinding, to open up the pores and create a surface the coating can grip. Crucially, moisture testing must be performed to determine if a moisture-mitigating primer is needed. Skipping these steps is a recipe for failure.
Prevent Bubbling and Damage With the Right System
This is where we differentiate ourselves. We often say, "The best epoxy for your garage isn't epoxy," because traditional epoxy systems simply aren't engineered to handle the unique challenges of Edmonton's climate. We use an advanced Floor X2 Fusion + Nano system instead, a polyaspartic coating that delivers superior flexibility, durability, and adhesion.
Our system is specifically designed to combat the root causes of bubbling. It includes a formidable moisture-mitigating primer that penetrates deep into the concrete, creating an unbreakable barrier against outgassing and moisture vapor transmission. Unlike epoxy, our polyaspartic system remains flexible in extreme temperatures, preventing brittleness and cracking. This is why we can confidently offer a 15-year all-inclusive warranty against peeling and moisture damage.
If you're dealing with a failing epoxy floor or want to ensure your new floor is done right the first time, don't leave it to chance. Our comprehensive
concrete repair and resurfacing services can address underlying issues before we apply our superior coatings. As a family-owned Edmonton business, we pride ourselves on our expertise and commitment to quality. Learn more
about us and
our garage floor coatings, and when you're ready for a floor that lasts,
contact usfor a free quote.