Category mold & air quality

Flooring fails from below when a slab is too wet. Here are the three tests, what the numbers mean, and the thresholds manufacturers actually require.

A vapor barrier on the wrong side traps moisture inside the wall. Here is what perm ratings mean, where barriers belong, and why basements are the exception.

Target 45 to 50 percent. Above 60 percent mold becomes active, below 35 percent causes its own problems. Here is how to measure and hold the right number.

A dehumidifier removes water from air. It does nothing about water coming through your walls. Here is where the line is, plus sizing and running costs.

Summer sweating is condensation, not a leak. Here is the dew point physics behind it, why ventilating backfires, and the fixes that actually work.

Where to look, how to distinguish mold from efflorescence, when testing is worth it, and the 10 square foot line between a DIY job and a professional one.