Surface PreparationQuestion 9 of 100
What tool or method best confirms whether a concrete slab is dry enough to coat?
a.A visual glance at the surface color
b.A moisture test such as a calcium chloride test or a plastic-sheet (ASTM D4263) test
c.Touching the slab with a bare hand
d.Smelling the surface for dampness
Explanation
Concrete can look dry on the surface while retaining moisture that causes coating failure. A calcium chloride test measures moisture vapor emission rate, and a taped plastic-sheet test reveals trapped moisture as condensation. Coating a slab that is too wet leads to blistering and delamination.
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