The surface of a slab does not tell its whole story. Before investing in a finish, understand the substrate’s moisture conditions and signs of water problems.
A reading must be interpreted in the context of the test method and selected system. A number without context cannot approve an installation.
Observe without jumping to conclusions
Efflorescence, persistent odours, previously detached coatings and stains after rain are useful clues. Record where and when they appear. A photograph taken in dry weather may not reveal the issue.
No visible stain does not prove there is no vapour. Testing and building history complete the assessment. An older slab can also differ from a recently repaired area.
Understand what a system can do
Some primers are designed to reduce vapour transmission under the conditions specified by their manufacturer. Their use depends on test results, preparation and compatibility with subsequent layers.
Active infiltration or water pressure calls for a separate approach. Applying a resin to the surface does not automatically solve causes related to drainage or the building envelope.
Share the relevant history
Report water damage, any known vapour barrier, drainage work and previous products. Do not hide stains before inspection: they may help explain the substrate.
Ask what checks are planned, which limits would require a different system and how work would change if the concrete is unsuitable. That discussion is more useful than a universal waterproofing promise.
Your checklist
- Water history shared
- Test method identified
- System limits checked
- Infiltration addressed before finishing
Recommendations must be adapted to the substrate and documentation for the installed system. This article does not replace a site assessment.
