Pros, is using my non-destructive moisture meter to measure concrete moisture sufficent testing, or should I think about performing calcium chloride tests as well?

Do you charge your clients to perform calcium chloride tests? I know the data is vital for successful floor performance, and it would be in my best interest to perform this test, but it's just that the test isn't exactly cheap (around $15 each) and it's much more time consuming than just reading my moisture meter. Also, if they show negative results for wood flooring installation and you won't even get the job.

Calcium Chloride tests are often mentioned by manufacturers as the preferred method of testing for moisture content in concrete slabs. Floorguy uses a Tramex Moisture Encounter that is also an accepted method of testing for moisture. Here's the thing about testing. The installer is responsible for determining if the substrate is appropriate for the floor covering he is installing. If that substrate is out of spec for whatever reason, he has the following options. Inform the owner of the problem and that the problem must be corrected (owner to pay ), decline to install the flooring or install and hope nothing bad happens. Too many installers choose option # 3 but what they don't realize is that by installing the flooring, they are basically saying the substrate is fine and the flooring will perform fine. If the floors do fail, the installer is on the hook, to a degree. Also, no matter which type of moisture test one does, it's a "snap shot" in time. Meaning, that is the MC at the time the test was done. It cannot say what the MC was 6 months ago or what the MC maybe in 6 months from now. So, often times, it is a good idea to inform the buyer of these facts and suggest a vapor/moisture, barrier/reducer as a form of insurance in case of future moisture problems. If they decline, then it's their choice. If you use a meter to test, I see no reason to charge for that if you are able to test during your first visit while you're estimating. A CC test should be charged for as it takes time and costs money, plus you typically need at least two of them. My opinion, for what it's worth.

Thanks Gary. I was thinking along the same lines, I just needed some reassurance.

I use my Tramex Concrete Moisture Encounter, to map the slab. I will place it down on about every sq.yard of the slab, to see if I can locate a "hot spot"

A CC test is what has always been accepted. It is outdated and can be compromised easily. You have to do 3 test sites per the first 1000 sq.ft.
So if it is a 300 sq.ft. room, you must place 3 tests, and then get an average from the 3, Now, I find this just like guess work. You have to make time for 3 days to do the test correctly. First you come and grind the concrete to clean the surface, then leave. The next day you come and place your teststs, making positive you have a really good seal with the concrete and the dome, then you leave. 72 hours after the dome is set, you return, to remove the domes and log the results.


Now the europeans have been testing concrete moisture by taking readings of the concretes internal humidity. They call it a 2071 test. It is actually the most accurate way of determining concrete moisture. Now, instead of a pounds per 1000 sq.ft., which is really what, how do you compute that to a moisture % since wood is measured in a moisture %. The 2071 is done by drilling a hole in the concrete, and leaving. Returning the next day, and placing and sealing the probe into the hole you drilled. 75% rH is the limit. If it is even close to 75%, corrective measures need to be taken.

Perry, a couple of questions.
When performing a CC test, why would you need to leave after the first day to come back a second day to place the test? I mean, clean the slab and set the test on the same trip. What's wrong with that?
Do the hardwood flooring manufacturers accept the European 2071 test procedure?

Because when you grind the surface of the concrete, it creates heat. Heat will alter the vapor emissions. High pressure/low pressure. Give it time to equalize. 12 hours is recommended, but a full day is better.

Why are we grinding the concrete to perform a CC test? Since most of the slabs I see are "finish" troweled but not EXTREMELY smooth ( like glass) and just need cleaning if dirty. I'll scrape of course and sometimes even wet mop and vac up the water. But I only grind high spots. If there aren't any, why grind? Keep in mind, I'm learning here too! I still do slabs on occasion and haven't had any problems with cupping and adhesive failures. Guess I'm fortunate.

It is to without a doubt, there are no sealers or contaminants that will alter the test. The big debate a couple of years ago, was did this grinding, create a chimney effect. Opening the concrete to allow only that space to breath vapors. I do not believe in CC testing. Not reliable, and certainly easy to contaminate.

Yes, CC tests cost money. I bill $100 for each test site placed. $300 minimum.

Compared to a quality meter like yours, the CC test seems antiquated. Why? Slow and expensive. I'd invest in that meter IF I did more slab jobs. But since I do so few, I typically either CC test or most often, recommend a vapor barrier/reducer. Sure would be great to be able to afford ALL the cool tools. I saw a device today called a racatac. It's been around awhile but this newer version got me to thinking about all the uses it could have for me on the job. So, I'm thinking about getting this model.

http://www.racatac.com/mrac.html