Garage Flooring and The Vapor Problem You Didn’t Know You Had

Before: A Garage Floor That Looked Great—Until It Didn’t

In Pennsylvania, a new garage flooring installation might look perfect at first—but a year or two in, things change. Peeling edges. Bubbles in the middle. A dull, stained finish that no longer holds up. Most homeowners assume it’s just age or poor materials—but that’s usually not the case.

The culprit is often moisture rising from the slab itself.

During: Understanding Moisture-Vapor Transmission (MVT)

Concrete slabs are far from solid—they’re full of microscopic pores that absorb and release moisture. Water in the soil beneath your garage travels upward through these pores in vapor form. This process is called moisture-vapor transmission (MVT).

In the Northeast, where rain and humidity are high, MVT is a constant threat. And in winter, when vapor trapped inside the slab freezes and expands, that pressure can stress coatings or even contribute to cracking. If the coating system doesn’t create a proper vapor barrier, that moisture can create:

• Blistering and delamination
• Salt and mineral buildup (efflorescence)
• Premature surface wear and damage

1-day garage flooring systems do little to stop this. They rely on quick-curing polyurea or polyaspartic coatings for both the base (primer) coat and top coat. As great as these coatings are as top coats, they’re lousy base coats. They simply cure too quickly to soak deeply into concrete and can only be applied thinly. They just don’t provide adequate moisture control and are more susceptible to high hydrostatic pressures.