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MMS- Are some unreliable with high RH?

#21
Quote:JD, your comments in post #11, would I be close if I parahprased them, in below-layman's terms, thus: MVER tests show how much moisture may emit through the top of the slab.RH testing show what actually will, when floor coverings are applied.

Pat, you got it backwards. Because of so many variables there is no way you can say what you see in a slab is going to come out the top, although it may.

Like my friend Bob Higgins asks, "How many good floors have you tested where the slab is reading high rh?"

I take it you read the thread I started over at Linkedin?
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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#22
No worries. Perhaps I should have used more general wording, i.e. "what is most likely to affect a flooring installation", rather than "what will come out the top". I was also responding to JD's quote of:

Quote:Believing that the MVER calculated under wildly varying conditions and then believing that the MVER of a concrete slab indicates the suitability for moisture sensitive flooring is flawed reasoning. We know better than that now.

This is why observing these debates on the most applicable and relevant method of testing in relation to floor coverings (and the accuracy on the figures they produce) is invaluable to me. I'm not suggesting I know what is right.

Yep, been on and commented on your Linkedin thread "testing after the app". Like I said at the top of this thread, I respect a manufacturer who actually insists that the performance of their product be tested by the contractor.

Immediately after I posted this, I went downstairs where there is a new batch of that very manufacturer's product and lo, they now have stickers on it saying "STOP! Have you moisture tested the slab?! You should do so before and after application". Whaddayaknow!
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#23
Pat,
There are some instances where I do no testing before or after. If the slab is on grade and has no vapor retarder and the facility wants to install a moisture sensitive floor there is no reason to test the slab. It has already failed and is not up to the flooring manufacturer's specifications.

I have seen many, many floors fail that have a low MVER. A very hard troweled floor slab has a mechanically sealed surface that will impede vapor release. These floors can measure as low as 2lbs MVER and still fail miserably in a short amount of time. This proves MVER is not a reliable test, and is not an indicator of a slab's readiness for flooring.

Now the ASTM for F1869 has changed in an effort to show a higher MVER. In my mind it's too late, we have a new method of reading floors by using the Wagner Rapid RH. There are far too many variables with MVER that we don't see with RH testing.

Think of it this way. A slab's RH indicates the potential the slab has for failure. If the slab reads 98% it has a very high potential to fail. It is full of percolating hydration and alkalinity. A slab that reads 70% RH has a low potential for failure. It has completed hydration and is stable.
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#24
(11-09-2011, 07:28 PM)CC Solutions Wrote:  Pat,
There are some instances where I do no testing before or after. If the slab is on grade and has no vapor retarder and the facility wants to install a moisture sensitive floor there is no reason to test the slab. It has already failed and is not up to the flooring manufacturer's specifications.

I have seen many, many floors fail that have a low MVER. A very hard troweled floor slab has a mechanically sealed surface that will impede vapor release. These floors can measure as low as 2lbs MVER and still fail miserably in a short amount of time. This proves MVER is not a reliable test, and is not an indicator of a slab's readiness for flooring.

Now the ASTM for F1869 has changed in an effort to show a higher MVER. In my mind it's too late, we have a new method of reading floors by using the Wagner Rapid RH. There are far too many variables with MVER that we don't see with RH testing.

Think of it this way. A slab's RH indicates the potential the slab has for failure. If the slab reads 98% it has a very high potential to fail. It is full of percolating hydration and alkalinity. A slab that reads 70% RH has a low potential for failure. It has completed hydration and is stable.

OMG here we go again! SadSad

Jd, that first statement is funny because I go over slabs all the time with wood and just a urethane adhesive like Bostik's Best, that have read in the high 70's with no MMS system underneath and no vapor retarder under the slab. I think it is more about the design, grading, run off from the roof, how large it is etc. Is wood not a moisture sensitive floor covering?

Then in your last statement you state the slab is stable if the rh reading is in the 70% range. So which is it?

I think the Wagner Rapid Rh is an invaluable tool and the best rh device out there but I don't strictly rely on it. Would I go over a slab thats testing in the 90 range without an MMS, most likely not.

Heck I am even leary of the newer one step adhesives that simply trowel on a double layer of adhesives. I did just use Bostik's new adhesive the Seal N Grip and the One Step on a stranded Bamboo but I did test first.
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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#25
I don't know the permeability of the wood flooring you use. My moisture sensitive flooring is solid rubber, which holds moisture better than most vapor retarders.

All the earth can be considered 100% RH when you put a slab over it. There is an unlimited supply of vapor ready to come into your slab. Without a vapor retarder under a slab, all sheet vinyl flooring, VCT, rubber flooring, linoleum and sports floors will not be approved for installation.

I would suspect that your wood flooring has a similar requirement.

When I say a slab is good at 70%, that is a slab that is isolated from moisture intrusion. Again, if there is a way for moisture to get into that slab and raise the RH, all bets are off and all adhesive warranties are invalid. That is something you should know when you are putting a floor down with any manufacturer's adhesive.

I checked with Bostik regarding the use of their Bostik's Best adhesive. They are pretty clear that it is NOT for concrete slabs without a proper vapor retarder. So any installation with their Best on a slab with no retarder would void the warranty.

"For substrates that have an MVER of greater than 12 lbs or an RH greater than 82% or for substrates where a vapor barrier is not
used or is not functioning below slab
, use Bostik Ultra-Set SingleStepor Bostik MVP4/Bostik Adhesive System. "
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#26
Quote:Then in your last statement you state the slab is stable if the rh reading is in the 70% range. So which is it?

I think he actually said "A slab that reads 70% RH", not a range. Blush excuse my pedantry...

I've never heard of Bostik Best. We use Ultraset or the low-foaming rigid (AV525 I think it's called).

Quote:If the slab is on grade and has no vapor retarder and the facility wants to install a moisture sensitive floor there is no reason to test the slab.

Funny story- friends just "renovated" their house, i.e. built a new house around the old one. It was all ultra-modern and swanky, the old house forming the downstairs level, which the couple hardly use. A year after the reno, we christened the downstairs ensuite by billeting some travellers for a weekend. A year after that, the new timber floors in the downstairs hallway cupped and lifted badly.

Turned out that the downstairs ensuite's plumbing had not been completed (the plumber died halfway through the reno- that's not the funny bit, obviously...) and the bathroom seeped everything into the soil under the slab.

Heck of a way to find out that the old house didn't have a retarder under the slab. They would be the perfect guinea-pig for some moisture testing practice, but I advised them that the slab may never fully dry.

Quote:I don't know the permeability of the wood flooring you use.

For interest's sake the timber in the above case was spotted gum, which has a high jenka rating, so I presume it is one of the "less permeable" timbers, yet it went crazy with the moisture. You guys have a lot of oaks, yes? Not quite as hard, I believe.

But then hardness and permeability might be a whole different thing for another thread....but ALL timber flooring is moisture-hyper-sensitive... Tongue

The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#27
Quote: I checked with Bostik regarding the use of their Bostik's Best adhesive. They are pretty clear that it is NOT for concrete slabs without a proper vapor retarder. So any installation with their Best on a slab with no retarder would void the warranty.

"For substrates that have an MVER of greater than 12 lbs or an RH greater than 82% or for substrates where a vapor barrier is not
used or is not functioning below slab, use Bostik Ultra-Set SingleStepor Bostik MVP4/Bostik Adhesive System. "

Or...or and or. But what if I test and my readings are under the prescribed limit?


The MVP4 is my fav, I like having a film that is totally set up to glue over verses the new one step products.

Hey, here is one of the leading underlayments for the industry as far as floating laminate and hardwood floors go. They claim it is 700 + percent more effective that other underlayments as far as moisture concerns go. See what test they require. Check it out;

http://www.floormuffler.com/ultraseal/installationinstructions.html
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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#28
Saw an add in Floor Covering Installer this month (came today) for Halex's Versashild and it claims to go to 95% RH. Going to circle that for info....
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#29
(11-10-2011, 05:13 PM)Ernesto Wrote:  Or...or and or. But what if I test and my readings are under the prescribed limit?


If your readings are under the manufacturer's upper limit and you meet all the rest of the requirements, you will have a warranty. Other requirements are a functioning and proper vapor retarder and a porous surface that has a profile to it, as Bostik says, 'not smooth but like a broom finish', as well as many other requirements.

If you miss just one required parameter the manufacturer has a way out, and for good reason! They know the floor moisture could skyrocket with no vapor retarder.


(11-10-2011, 05:13 PM)Ernesto Wrote:  Hey, here is one of the leading underlayments for the industry as far as floating laminate and hardwood floors go. They claim it is 700 + percent more effective that other underlayments as far as moisture concerns go. See what test they require. Check it out;

http://www.floormuffler.com/ultraseal/installationinstructions.html

How is this a good vapor mitigation system? The instructions are " If installing over concrete, the concrete must be dry with moisture emission rates that do not exceed 3 lbs. per 1000 square feet per 24 hours as measured by the Anhydrous Calcium Chloride Test."

Sounds like it has to be dry before you even start! Tongue
(11-10-2011, 05:16 PM)eaadams Wrote:  Saw an add in Floor Covering Installer this month (came today) for Halex's Versashild and it claims to go to 95% RH. Going to circle that for info....

There are hundreds of products that claim to 'go to 95%' or more. Why not stick with the three or four that actually work? Huh
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#30
(11-10-2011, 07:08 PM)CC Solutions Wrote:  If your readings are under the manufacturer's upper limit and you meet all the rest of the requirements, you will have a warranty.

Nope, I've never seen a flooring manufacturer warrant a floor based on initial testing. If you have a failure and at failure time there is higher moisture than specs allow, the manufacturer walks. Needless to say, if you look at anything hard enough you can always find something to void a warranty.

(11-10-2011, 07:08 PM)CC Solutions Wrote:  There are hundreds of products that claim to 'go to 95%' or more. Why not stick with the three or four that actually work? Huh

Yep I agree. I was looking at the products specs, only ok for tile, not resilient. So it is ... kinda a joke. I'll stick with the four products I know to work but the issue is always that I have to make sure subs don't use products like that.
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