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JD's ref: RH and MVER conversion explanation

I occasionally do testing for IFTI they require MVER, RH testing, PH and surface scan. Never could figure out why MVER until I read JD's post.

Also the last job I did for them was a 35,000 sf space that had been empty for a long time. Well we had a downpour, rare in El Paso, that lasted 45 minutes.
It was then that in the rear an incredible amount of water leaked onto the floor in the back section. Not near where I had 3 sites.

So I now see why they have me do them all now. RH for deep and MVER in case the top has moisture not evident deeper down. Boy, I am getting an education here!

I am not a big fan of doing RH and MVER since it's possible to have an acceptable MVER but high RH. The decision makers then base the installation approval on the low MVER only to experience a failure when the RH builds within the slab. I only do MVERs if it's insisted because the floor covering or coating manufacturer doesn't recognize RH for their product.
JK Nixon
Concrete Restoration Services, LLC
Pittsburgh, PA

The two tests are not related as they quantify two different principles. The MVER test tells you what is happening with the top 1/4" of concrete, the RH test tells you what conditions are inside the slab.

99% of the time the top of the slab is an open book and you don't need to test it to install flooring. I should say that was true about the old 1869, I haven't done any revelationalistic testing utilizing the new MVER standard. ( I make up words as I need them Tongue )

The only reason I would feel the need to test for MVER is if a slab was recently wetted or was not climate controlled previously. Adhesive bond strength can be adversely affected by high levels of surface moisture. This moisture doesn't allow the adhesive to absorb, the carrier water to dissipate and the adhesive bond to occur as it should. This results in a lower tensile strength bond which can fail under stress.
JD Grafton
Concrete Answers for Flooring Problems

Everyone should be reading the last two issues of Concrete Construction. Lee from IFTI did an article on CC testing. This month they had some others do a kinda softball counter argument. I'm QUITE surprised there wasn't a more significant article on RH. But perhaps that is coming with the silicate article they better produce after this year's ... bitchfest ... online after the WOC lunch discussion.

I personally use IFTI some times. However, I have discovered some of their testers trying to side sell work on these projects. Not appreciated since I'm the one that sent em there. And then I put a note in the database and said bye bye to that region for IFTI testing.

I also thought that last article was WAAAYYY to soft. I was disappointed.
JD Grafton
Concrete Answers for Flooring Problems

Wagner did take advertising out next to the article, I hope cc magazine does something more. I think the point of the current article was to show the variance in cc testing not to promote another type.

They have to walk a fine line. As people realize that the experts have financial interests in the corps that make testing devices and solutions you have significant conflicts in interest. I believe some have interests in Wagner and others have interests in stego as a big proponent of airidus.

It is hard. It is a small industry and people need to make money. And the industry (concrete moisture) isn't big enough to let people be experts in knowledge and make a good living.

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