Moisture mitigation is the process of treating a concrete slab with a vapor barrier coating or membrane to block excess moisture vapor from reaching a floor covering or coating above it.
Understanding Moisture Mitigation in Concrete Flooring
Concrete is porous, and slabs on or below grade constantly pull moisture up from the ground through capillary action. Moisture mitigation systems, usually a two-part epoxy or specialized penetrating sealer, are applied directly to the slab to create a barrier that keeps that moisture vapor from reaching the flooring or coating installed above it.
What Determines If Moisture Mitigation Is Needed?
The decision usually comes down to testing. A calcium chloride test or relative humidity test measures how much moisture is moving through the slab, and most coating and flooring manufacturers publish a maximum acceptable reading in their technical data sheets. A slab that fails that threshold needs a mitigation system before any moisture-sensitive coating or flooring goes down.
Moisture Mitigation vs. a Vapor Barrier
A vapor barrier is typically a plastic sheet installed under a slab during construction to stop ground moisture before it ever enters the concrete. Moisture mitigation is applied after the fact, directly to the surface of an existing slab, which makes it the go-to fix for older buildings or slabs that were poured without a vapor barrier in the first place.
Practical Tips for Moisture Mitigation Projects
Always test before you coat rather than guessing, since a moisture problem that goes unaddressed will fail even the best topcoat. Follow the mitigation product’s own surface prep and recoat window closely, since these systems are often less forgiving than standard flooring epoxies. Budget extra time for mitigation work on renovation projects, since it adds a full application and cure step before the finish flooring can go in.
Also Called
Moisture Vapor Mitigation, Vapor Mitigation System
