pinless moisture meters with drywall

September 10, 2009 2:18 PM

How accurate are the pinless moisture meters when used on drywall?

We are contemplating buying an older house (1900's) in the Pacific Northwest with a finished basement. We realize moisture could be a problem and would like to purchase a moisture meter to keep an eye on it.

The meters with pins seem to work really well, but if we want to test the moisture in the basement often, then we would end up with little holes all over the drywall.

From google, it seems the more common use of moisture meters is for wood, not drywall, so it wasn't clear (to me), if a pinless one would give accurate results with drywall.

Does anyone have any first-hand experience using the pin meters vs pinless meters? How accurate are they in general? With drywall? Why wouldn't you purchase a pinless one vs. one with pins if they were equivalent?

Any other information about monitoring moisture inside of a finished basement would be greatly appreciated!

posted by j to home & garden (6 comments total)

I've generally heard that the inexpensive meters aren't very good. Here's a little discussion at toolmonger.
posted by electroboy at 2:50 PM on September 10

Some additional discussion here. The jist of it is, if you get a reading, is it accurate? If so, do you know what is an unacceptably high reading?

This indicates you'd want < 12% Relative Humidity, but the source documentation isn't really clear.
posted by electroboy at 2:59 PM on September 10

Thanks, electroboy.
We are probably going to buy one of the more pricey ones (worth it for peace of mind!).
And that's what I was struggling with -- how accurate are the readings? Does it really matter if there is +/-5% accuracy if the relative numbers are at least correct? But, are the relative numbers even correct?
I'll continue my google search...
posted by j at 7:54 AM on September 11

You may not have to buy one. There are a lot of companies that rent test equipment, mostly to engineers and inspectors, but they'll rent to the general public as well. Example here. Try googling for environmental equipment rental, industrial hygiene rental, along those lines. An additional benefit is that they usually have someone on staff that can instruct you on usage and can give you an idea of the accuracy.
posted by electroboy at 8:31 AM on September 11

Also, if you find a good deal online, most rental companies will ship equipment to you. Just keep in mind that the rental time usually includes the time in transit.
posted by electroboy at 8:45 AM on September 11

Thanks again, electroboy. I'll look into that as well.
posted by j at 10:01 AM on September 12