Replies

1. 
   airfix | Apr 02, 2019 09:10am | #1

   I've thought about doing the same thing but I've not yet found a solution.

   Maybe some kind of Jimmy rig might work. Those pin type hygrometers work on electrical resistance. In theory you could "extend" the pins through your drywall using an electrical circuit. However it will surely affect your results but maybe with some calibration tests before install you could get relative results?

   I'm interested to see if anyone else here has done what you are looking to do.

   Steve

1. 
   lance_p | Apr 02, 2019 11:47am | #4

   I was wondering the same; could I just attach insulated wires to the back of the sheathing with small screws, run the wires inside, and use the moisture meter across the wires?

   I guess I could do a mock-up and see what the results say.

2. 
   Yupster | Apr 02, 2019 09:16am | #2

   Did you see this article? https://www.greenbuildingadvisor.com/article/extending-the-reach-of-a-moisture-meter

1. 
   lance_p | Apr 02, 2019 11:45am | #3

   Yes I read that a while back. If possible I want to avoid having to puncture my drywall and vapor retarder to get a reading.

   I was hoping to come up with something like they used for the BSC study, but that’s affordable:

   https://www.buildingscience.com/documents/bareports/ba-1501-monitor-double-stud-moisture-conditions-northeast/view

   As far as I can tell they don’t specify the equipment they’re using.

1. Expert Member
   BILL WICHERS | Apr 02, 2019 12:32pm | #5

   Page 10 of that document gives some detail as to what they used to make their measurements. Temperatures were measured with thermistors, which are very reliable when also very inexpensive. Humidity was measured by capacitive sensors which are pretty standard for this, but more complex to use (an interface usually converts the variable capacitance to a variable frequency which is how the sensor is read). There are also humidity sensors that have integrated interface electronics and provide a voltage output.

   The wood moisture content is measured with pins in the wood. This is pretty much how the standard moisture meters work. If you were to make a system like this to embed into a structure in some location that would be inaccessible after construction was completed, I’d use durable materials for the sensing elements. I would use stainless steel pins (titanium would probably be best, but it’s much more difficult to source), and I’d ideally use nickel plated copper wire with Teflon insulation. The easiest/cheapest DIY option would probably be stainless steel screws as probes, and a standard twisted pair wire to bring the signal out. I would use crimp lugs (good ones like Amp solistrand or PIDG terminals) to connect the wire to the stainless screws. Run the wire through the structure to wherever you want to connect your metering equipment.

   B and B electronics makes a lot of monitoring equipment that can read the data and provide a data interface for logging and long-term monitoring.

   Bill

3. 
   Peter Yost | Apr 02, 2019 02:10pm | #6

   OmniSense has moisture content sensors that can be located interstitially (inside framing cavities) and read/downloaded remotely:

   - https://www.omnisense.com/Store/wireless-sensor

   Peter