How to Do Moisture Testing for Epoxy Floors (Beginners Guide with Tools)
- Mar 2
- 2 min read
If you’re installing epoxy floors—whether in a garage, warehouse, or commercial space—proper moisture testing is one step you cannot skip. Moisture trapped beneath epoxy can lead to bubbling, peeling, and complete coating failure. This guide breaks down how beginners can run accurate moisture tests using affordable tools and proven methods.
Why Moisture Testing Matters
Concrete may look dry, but it naturally contains moisture that moves upward as vapor. When epoxy seals the surface, this vapor becomes trapped, creating pressure that breaks the bond. Industry experts and epoxy manufacturers frequently recommend moisture evaluation before any coating installation to avoid warranty issues and expensive failures. Testing ensures the concrete is dry enough for epoxy adhesion and long‑term durability.
Tools You Need for Moisture Testing
Beginners can confidently perform tests using these common tools:
A handheld concrete moisture meter gives quick surface readings. Although not the most precise method, it’s great for early evaluation and identifying problem areas.
2. Plastic Sheet Test (Basic Screening)
A plastic sheet taped to the slab for 24 hours can indicate visible condensation. While simple, it is not ASTM-compliant and should only be used for preliminary checks.
This widely recognized test measures the Moisture Vapor Emission Rate (MVER). You'll use:
Calcium chloride test kits
A sealed test dome
A digital scale
Most epoxy manufacturers specify an acceptable MVER limit in their instructions.
4. In‑Slab RH Test (ASTM F2170)
The most accurate method involves drilling small holes and using sensors to measure relative humidity inside the concrete slab, giving deeper insight into moisture conditions.
Step-by-Step Process
Clean the surface – Remove dust, grease, and coatings.
Choose your testing method – For beginners, start with a moisture meter or plastic sheet test.
Run the test following ASTM guidelines – This ensures results match professional standards.
Compare results with epoxy manufacturer requirements – Never apply epoxy if moisture is above recommended limits.
Fix moisture issues if needed – Options include dehumidifiers, vapor barriers, or moisture‑mitigating primers.
When to Get Professional Support
If results are borderline or the slab shows signs of hydrostatic pressure, a professional flooring contractor or moisture specialist can conduct more advanced testing.
Protect Your Epoxy Flooring Business
If you’re a contractor offering epoxy flooring services, proper moisture testing is not just best practice—it protects your business from liability. For tailored contractor insurance, visit Wexford Insurance to request a fast, no‑obligation quote.
