When a vinyl floor bubbles or an adhesive turns to soup, the finger usually points at the installer. In our experience the real culprit was in the slab the whole time, and a two hundred dollar test would have caught it.
What we actually measure
We use in-slab relative humidity probes to ASTM F2170 rather than surface calcium chloride tests alone. Probes read the moisture deep in the slab, which is what will eventually reach the adhesive, and they keep reading as the slab dries.
For older buildings we add a simple plastic sheet test and a look underneath wherever access allows. Groundwater, missing vapour barriers, and failed perimeter drainage are common in buildings poured before the 1990s.
What the numbers mean
Most resilient flooring manufacturers cap installation at 75 to 85 percent internal RH. Go above that and you void the warranty, whatever the adhesive salesman says. New slabs need roughly thirty days of drying per inch of thickness in good conditions, and a rainy Lower Mainland winter is not good conditions.
Fixing a wet slab
You have three options: wait, mitigate, or change the system. Waiting is free but rarely available. Mitigation means an epoxy moisture barrier primer, which adds cost but carries its own warranty. Changing the system means choosing a breathable or moisture-tolerant floor instead.
We put the test results and the recommendation in writing before any material is ordered. It makes the conversation with your insurer much shorter if something ever does go wrong.