Slab moisture test

Definition

The relative humidity read from inside a concrete slab before anything is glued to it.

Why It Matters

Moisture is the cause of most flooring failures over concrete, and the maker's warranty is written to require documented testing, so a shop that does not test carries the tear-out and the reinstallation itself. The in-situ probe method is the current one; the older surface method measures something different and is not interchangeable with it. Ask for the reports on the last twenty commercial jobs. A shop with none is carrying an unpriced warranty book that arrives with the company.