Why Do Epoxy Garage Floors Peel or Lift

Most people blame the coating when a garage floor peels, and almost never look at the slab underneath. The failures below repeat across Riverside, CA, and the breakdown sitting on epoxy floor installation riverside clytemnestra project lists them in order with the mechanical cause of each. Nearly all of them trace back to what happened on the concrete before any epoxy was mixed, or to what was left off the top of it.

Peeling and delamination

Peeling is a bond failure, and the bond is made or lost during surface preparation. Coating over smooth troweled concrete, sealed concrete or concrete with oil in the pores leaves nothing for the primer to grip. Diamond grinding opens the surface so the material can key in. Skipping it, or using acid etch alone, leaves a film sitting on top of the slab instead of locked into it.

Hot tire pickup

Tires heated by driving soften a thin or weakly bonded coating, and plasticizers from the rubber help lift it. The result is tire-shaped patches pulled off where the car parks. Long summer drives in the Inland Empire push tire temperatures higher, so a marginal system that survives a mild climate can fail here. Adequate film thickness and a hard urethane or polyaspartic topcoat reduce the risk.

Blisters, pinholes and craters

Moisture vapor pressure from below can push through the slab and form blisters, or break the bond across a whole area. Pinholes and craters usually come from outgassing. If the slab warms during application, air in the concrete rises through the wet base coat and leaves holes as it cures. Applying while the slab temperature is falling, and rolling the primer in thin, helps keep that air from escaping into the film.

Yellowing in sunlight

Epoxy is not UV stable. Where sun reaches a floor, such as the strip near an open garage door, an epoxy without a UV stable topcoat will amber over time. Pigment type does not prevent it. A polyaspartic or aliphatic urethane clear coat over the color, whether solid color, vinyl flake or metallic pigment, holds the original shade far longer.

Cracks and failed recoats

Cracks that move with the slab will usually reflect through the coating even after repair. Filling a crack with a semi-rigid repair material closes the gap, but the coating does not stop the slab from moving, and the line often returns. Recoats fail differently. Once the recoat window has passed, the cured surface is too hard for the next layer to bond to. Without abrading it, the top layer can peel from the layer beneath, sometimes in sheets, because the break is between coats rather than at the concrete.