Pins measure between two points at a known depth. Pinless meters read a field over a volume.
What pins do better
They give a specific reading at a specific depth in a specific material, and the good ones carry calibrated scales for different wood and building material groups — one meter we compare has seven. They leave two small holes.
What pinless meters do better
They survey. A ball sensor reads to a stated 40 mm (1.57 in) without marking anything, which is the only option on a decorated wall where a survey means dozens of readings.
The pinless trade-off
The field does not discriminate. Forty millimeters of wall containing a metal conduit, a mesh or a foil-backed board will read wet whatever the moisture content. That is why the technique is many readings compared against each other rather than one absolute number.
What neither does
Diagnose. A high reading is consistent with rising damp, a leaking pipe, condensation and splash-back, and no meter separates them. Take a reference reading somewhere you believe is dry, compare, and hand the interpretation to someone qualified.
What gets asked here
Why do wood scales come in groups?
Because electrical resistance at a given moisture content varies by species. A meter with one scale is right for one wood and approximate for the rest.
Can I use a pin meter on a plastered wall?
You can, and it leaves two holes each time. For masonry surveys the pinless instruments exist precisely to avoid that.
Last reviewed 31 August 2026