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Bad, Bad Testing

#21
Frustrating isn't it Jim? Tongue

It's a wonder how anything stays down sometimes.

I had a job once that just about every conceivable installation failure happened. Improper prep, WAY too wet slab, improper trowel size, improper patch mixing, improper glue set times, improper temperature during install, I couldn't find anything that seemed to be done right, yet for the most part the floor was holding.

It held for quite a few years! Then when it let go, what a mess.

Oh, and not to be picky, but we are on a site dedicated to concrete moisture issues, so here goes:

You started off saying "Question 1 what was the mc of the concrete?" and that would be difficult to assess and require lab testing... Blush

I think you meant to say "what is the relative humidity of the concrete".

Correct me if I'm wrong. We could have a looonnnggg discussion on the difference between moisture content and relative humidity and even moisture emission. In fact sometimes we do! Tongue
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#22
Using a tramex concrete moisture meter which reads in moisture content 4.5% = 75% Relative Humidity. My Lignomat Versa Tec reads surface scans in relative humidity also. But I forget to adjust accordingly.
If surface scans show 2% to 3% mc we proceed in El Paso due to extreme dryness. If it gets near 75%, pretty rare here usually 2% to 2.5% then definitively utilized insuti testing. For wood RH 75% or less is acceptable.
I got started testing with IFTI which required insuti testing, CC, PH and surface scans in each test area.
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#23
Where do you find the certification from Tramex (or anyone as far as that goes) that 4.5% = 75% RH?? Huh

Electrical impedance meters are easily fooled by composition, steel reinforcement and other factors. Do you have any manufacturers that honor EI readings?
JD Grafton
Concrete Answers for Flooring Problems
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#24
Ok to clarify mc and rh see tramex attachment top shows h2o or mc bottom shows RH lining them up 4 1/2% mc = 75% rh.
Hoadley's book defines it quite well RH controls MC and MC controls dimension. So if I get 4.5% mc on my meter it took a prolonged period of time at 20% relative humidity to that to happen and typically the wood wood have some slight gapping with solid wood. That is the other chart from the NWFA that depicts all of this. I know it is confusing took me a long time to get my head around it.

JD your right what was I thinking. It has no lineal correlation strickly for comparative or qualitative scale only. See attachment. So much too keep straight.

Correct tramex instruction sheet.


Attached Files
.jpg   Tramex meter with RH comparatives for forum.jpg (Size: 85.35 KB / Downloads: 5)
.jpg   Moisture Content of Wood Table.JPG (Size: 408.31 KB / Downloads: 2)
.jpg   Tramex meter with RH comparatives for forum.jpg (Size: 85.35 KB / Downloads: 4)
.pdf   tramex.pdf (Size: 108.05 KB / Downloads: 3)
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#25
I was gonna say!

I never noticed that scale on the old MC Meter. Well, that answers that question. It's not RH%! Back to where we started.

Remember JD way back when I first waddled into this forum, with my nappies and training wheels, we were all using MC Meters down under and some spec sheets still call for the ubiquitous old 5.5% maximum threshold of MC, up to which everything is great, slap down a floor.

Indeed some installers still tell me "it's okay, I tested the concrete it was under 5.5%.".

Now the new resilient standard and many spec sheets tell you to forget MC, but don't throw your meters away just yet- they're good for mapping out where you should do further RH testing.
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#26
Thanks Jim, I was gonna blow a fuse if someone was telling you that somehow moisture content correlates to RH. We've had discussions on this forum for years regarding that very issue.
And besides, the Tramex should always be used as a qualitative measuring tool, never a quantitative one. Wink

Yes Pat, that seems like many moons ago when you first came to us, all bright and shiny and ready to add your input. What a great contributor you have been!! Cool

How are things on the flip side of the planet? What do you guys think about Iran and Israel and all the world news? We're going to war soon... are you in? Exclamation
JD Grafton
Concrete Answers for Flooring Problems
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#27
Yep. I actually know stuff now, I does... Lightbulb

Current events? You shouldn't have opened that can o' worms, I will rabbit on until Jason kicks us off for getting too political on a moisture meter forum. (AND rightly so!!)

By strange coincidence, this very evening just gone (yesterday morning your time) I caught up with a Jewish friend who is very plugged in to his community here (apparently the largest outside Brooklyn). He reckoned you guys have lost the political will to go trying to punch-on with Iran.

But if you do decide to help take on the Persians and their nukes, then sure, why not...we'll tag along. Sure we can find some spare diggers and maybe some FA-18s. We'd have to pull 'em out of an airshow or something....

Hey, while we're talking about that, where the heck are the F 35's we ordered from you guys? We left a $1.3b deposit and you're not returning our calls!
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#28
I suppose we better stay on topic, Sorry... Tongue
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#29
(12-22-2012, 01:02 PM)CCR Wrote:  Just yesterday, I read the installation specs for a sheet flooring from a well known flooring manufaturer who actually stated in their literature to install based on the lower of the two test results Huh

Which company was that? I have seen some installation guides that talk about taking the worse of the two results. I have also seen manuals that give you a higher tolerance of cal chlor results if you have RH results of xx or higher, than if you perform only cal chlor, but what you described will be a new one to me. I hope it is not a product I use on a regular basis. Confused

(03-21-2013, 12:02 PM)CC Solutions Wrote:  Frustrating isn't it Jim? Tongue

It's a wonder how anything stays down sometimes.

I had a job once that just about every conceivable installation failure happened. Improper prep, WAY too wet slab, improper trowel size, improper patch mixing, improper glue set times, improper temperature during install, I couldn't find anything that seemed to be done right, yet for the most part the floor was holding.

My experience is limited, about 12 years, but it holds because the adhesives we use are not TOTAL junk. It will take at least a few years depending on circumstances for the adhesive to fail. Being a flooring subcontractor, and knowing my local competition, that is all that matters. Most of my competitors and the GC's I work for, all they care about are getting past our 1-2 year installation warranty. When GC's ask me why moisture has never been a problem until now, I answer with this... Moisture has always been a problem. Most people have just chosen to ignore it. Commercial floors only last for X number of years before it is not attractive anymore, and the owner wants to replace it anyway. Especially when owners ignore maintenance, like most do. Also, my competition, just needs to get past their warranty and they are out of the loop. Even the cheapest adhesives will stick for a year. It is very sad that the industry is like this. Especially in Atlanta, where there is SO much work.
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#30
Geez...that was 3 months ago.Huh I can't recall what I had for breakfast. Like many other other contributors, I shy away from making less than positive comments about particular manufacturers in this forum. Best advise it to just keep your eyes open to what's specified for the job being tested and proceed accordingly.
JK Nixon
Concrete Restoration Services, LLC
Pittsburgh, PA
http://www.rhtester.com
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