You may be able to spot moisture in your basement just by taking a look, but it takes a pro to tell you how long before you will need a whole new basement floor. Great engineering minds have come up with bunch of tests that can tell them how much moisture content or vapor is coming through your concrete slab. These include:
• The Plastic Mat Test (ASTM D-4263)
• The Calcium Chloride Test (ASTM F-1869)
• Gravimetric testing
• Radio Frequency testing
• Nuclear Density testing
• Electrical Capacitance testing (moisture content meter).
As luck would have it, only two of these are actually worth a plugged nickel. Only the Plastic Mat Test and the Calcium Chloride test give an accurate reading of moisture vapor transmission over time, which is what ruins most floor finishes.
The other test methods are like those old Polaroid cameras that give you a snapshot of moisture contained in a concrete slab at a particular moment. For example, a slab may be damp from rain and test with a high moisture content, but several days, after the water evaporates, vapor transmission levels will quickly return to normal levels, if there is no other source of moisture. So, it's a wash.