Module 4 · Tools & Equipment
4.1 Moisture Meters: Pin & Pinless
8 min read
The moisture meter is the instrument most associated with damp surveying and the one most often misused. It does not measure moisture. It measures an electrical property that usually correlates with moisture, and sometimes correlates with something else entirely. This lesson covers both types, what each is genuinely good for, and how to use them so the numbers mean something.
Learning objectives
By the end of this lesson you will be able to:
- Explain what pin and pinless meters actually measure.
- Select the appropriate meter type for a given surface and question.
- Take readings that are comparable rather than isolated.
- State meter findings in terms the readings can actually support.
Key terms
- Pin (resistance) meter
- Measures electrical resistance between two pins pushed into the material. Lower resistance reads as higher moisture.
- Pinless (capacitance) meter
- Emits an electromagnetic field into the material and measures how it is affected. Non-invasive, typically 10–20mm deep.
- WME
- Wood moisture equivalent — the scale most pin meters report on, calibrated for timber and only indicative on masonry or plaster.
- Reference reading
- A reading taken on a comparable, unaffected area, so an affected reading has something to be compared against.
Read the rest of Tools & Equipment
Module 1 is open to everyone. The remaining six modules — building science, each damp mechanism in depth, meters and thermal imaging, the full inspection method, and report writing — are free too. We just ask for an email so you can pick up where you left off, and so we can send your certificate when you finish.