Detecting wet insulation in stud bays

I’m looking at a wall I know is leaking, and has moldy wet cellulose in two stud bays. It’s definitely mold, the smell is very strong.

I have three tools available: a pin moisture meter, a non-contact moisture meter, and an IR camera (a low end Flir One). I’m unable to detect much of any difference between the wet stud bays and the dry ones.

Possibly this is because the cellulose holds a lot of water, but is inconsistently wet. I’m finding the first inch or so against the wet sheathing is soaking wet, but the stuff near the wall is pretty dry. The exterior is stucco.

Or… is there a way to use the tools for this task?

What are trying to accomplish?
Hard coat stucco over W/F?

How do you know the insulation is wet, are the walls opened?

A pin probe meter will give you fairly accurate results, but the water or moisture has to migrate to wherever surface you’re probing.

Learn the limitations of an IR scanner to know why you’re unhappy with the results.


If the interior is dry you likely would not be able too image it. On the outside you may be able to see something though. A flir 1 would not see much though. A moisture meter is you’re best bet in this case.

You need more aggressive tools.

You already know its leaking.

A deep probe attachment on your meter (from the inside) is best for that situation. Slightly invasive but easily repaired.

Call a Stucco Inspection company. You don’t have the right tools apparently. Is your contract set up for invasive inspections? Stucco inspection insurance?