A moisture meter is one of the most consequential tools in a home inspection. Used at the right locations, it confirms or rules out hidden water issues that visual inspection can only suspect. Two types exist: pin meters (which use small probes to read electrical resistance through the material) and pinless or capacitance meters (which read moisture in the top 20 to 40 mm of material non-invasively).
In a Calgary home inspection, the inspector uses a moisture meter at specific suspect locations rather than scanning every surface. Locations include: any visible staining on walls, ceilings, or floors; under all plumbing fixtures; at basement floor-wall joints, particularly after recent precipitation; around windows and exterior doors; at any thermal-imaging finding suggestive of moisture; and at known risk areas like below dishwashers, refrigerators, and washing machines.
Readings are interpreted relative to baseline. Drywall typically reads 0.5 to 1.0 per cent in equilibrium with normal interior conditions in Calgary; readings above 1.5 per cent in drywall suggest moisture issue. Wood framing typically reads 8 to 12 per cent in equilibrium; readings above 16 per cent indicate moisture, and above 20 per cent is a fungal-growth risk over time. Concrete reads on a different scale and requires interpretation against location and condition.
What moisture meters cannot do: distinguish between active and historical moisture, predict whether moisture is increasing or decreasing, or identify the source of moisture. A high reading documents a condition; root cause investigation is a separate step, often involving plumbing inspection, drainage review, or invasive opening of finishes.
For Calgary buyers, moisture meter findings should be addressed before condition removal. A confirmed elevated reading in a basement wall after a known wet spell may simply reflect drainage that needs attention. A confirmed reading under a kitchen sink suggests a current plumbing leak that the seller may not be aware of. The inspection report documents readings with context; further investigation by a plumber, restoration contractor, or exterior drainage contractor follows when warranted.
