Deep wall probe for cavities and insulation
A two-pin probe with long insulated 608 pins, for checking moisture inside a wall cavity, behind render or cladding, or under roofing without opening the structure up.
Why the insulation matters here
On the way to the insulation the pins pass through plasterboard, an air gap and whatever else is in the cavity. An uninsulated pin would report the wettest of all of it and you would not know which. The 608 pins are bare only at the tip, so the reading belongs to the depth the tip has reached.
Fitment
Specifications
| Model |
21-E |
| Pins |
608, Teflon insulated except at the tip |
| Maximum penetration |
3 1/4 inches (82.6 mm) |
| Applications |
Insulation behind drywall, stucco, roofing materials |
Choosing between the variants
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21-E — 608 pins, 3 1/4 inch penetration. This listing.
-
21-ET — same pins, tapped handle so an extension pole can be fitted for high or awkward areas.
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21-E/001 and 21-ET/001 — fitted with the longer 608/001 pins for deeper cavities. Not listed here; ask us.
Frequently asked questions
Does it leave a hole?
Two small pin holes in the surface, which is the point — it is the least invasive way to find out what is happening in a cavity.
Can I read the moisture content of insulation itself?
Resistance meters are calibrated for wood. In insulation, treat the reading as comparative — wetter or drier than the reference area — rather than an absolute moisture content.
Will it reach through a double-layer wall?
Maximum penetration is 3 1/4 inches. For deeper cavities you need the /001 variant with the longer pins.
For every other Delmhorst pin and retainer, see the Delmhorst Contact Pins and Retainers Guide (PDF). For timber species corrections, see our Australian Timber Species Correction Tables and the general Correction Tables.
Not sure which part fits your meter or electrode? Send us the model and what you are testing, and we will confirm the correct part before you order.
