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Substrate Odor

#1
I was called upon to perform RH tests at an office last month. A full blown ASTM compliant test for size of space was not approved due to cost, so we agreed on placing 6 sensors in random locations including 1 location where a strong midew odor was present under the rubber backed carpet tile, bonded with an unknown brand of pressure sensitive adhesive.

The carpet was extremely well bonded in all test areas, and it even took 2 of us to pull up a couple of carpet tiles . There was also obvious old Dependable patch material under the mildew area and another location which I believe are causing the odor problem. Readings were 70% - 82%, with the highest at the mildew location.

The customer indicates that the carpet is cleaned every 6 weeks or so, and the water is all but fully extracted when complete.

I recommended that the effected areas (with gypsum) plus a 5-6' perimeter be shot blasted to remove all adhesive, remove all gypsum patch. skim as needed with Ardex FF and re-install the tiles. To me, this was a conservative approach compared to installing a moisture mitigation system when it may not be needed. Remember, bonding is not the issue - it's the smell in 2 areas.

I was called back this week to conduct follow up readings and found nothing had been done but replace the tiles with more adhesive. The worst mildew spot was not carpetd and still open. In that location, the RH jumped from 82% to 96%!!! Two other locations spiked 10% and 7%, yet have no odor issues.

The building engineers told me the French drain system below the worst area is so dry it has cob webs. So this makes me still go back to the gyp patch scenario. I should point out the concrete is about a CSP-3, and is about 15 years old. I should also point out that when carpet is replaced, they just slap down more pressure sensitive. Wonder if the build up is blocking moisture(?)

I would welcome any input.

Thanks!!!!!
JK Nixon
Concrete Restoration Services, LLC
Pittsburgh, PA
http://www.rhtester.com
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#2
Hmmm... Did they clean the area you opened and perhaps saturate the concrete?

Did your test somehow hit a crack in the lower horizon of the concrete? The ground has very high RH, so if somehow you were picking up some of that moisture..... Maybe your test landed over a cut or seam in the vapor retarder?
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#3
It's a 5" slab with no vapor retarder. They did not clean anything between readings. In fact, nothing was done in the area (office cubicle) where the highest reading and worst odor are. The cubicle is vacant. The employee refused to work in it. Frankly, I think this person is either the most odor sensitive person on earth, or an employee who likes to raise a stink Rolleyes (no pun intended). I had to get down on my knees to smell anything, and it wasn't that strong (and I have a good sniffer)
JK Nixon
Concrete Restoration Services, LLC
Pittsburgh, PA
http://www.rhtester.com
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#4
No vapor retarder? So the moisture levels in the concrete are at the mercy of Mother Nature.

If it were my client, I would explain that no moisture sensitive flooring is recommended over concrete without a functioning vapor retarder (for these very reasons) and maybe suggest a polished concrete floor or a mitigation system. Wink
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#5
I agree, and I did mention that the best potential solution was a MM system over the odor area, extending out a few feet beyond. Polished concrete is not feesible as this is a customer call center and carpet tile provides necessary sound deadening benefits. Again, the carpet tile is well bonded, and the adhesive is not breaking down. It's just the one stupid cubicle / location. My logic still drives me back to the gyp patch, which has possibly been affected for a long timem, and finally reached a point where it's giving off odor. I say, remove it, grind it, Ardex it, and see what happens before disrupting the operations of the business and expense with the installation of a MM system.

At this point, they have my recommendation. As they say, you can lead a horse to water, but you can't make 'em drink.
JK Nixon
Concrete Restoration Services, LLC
Pittsburgh, PA
http://www.rhtester.com
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#6
I agree the Dependable is not the product you want on a slab that has no vapor retarder, is on grade and has elevated moisture levels.

If you are willing to go so far as to remove the patch, at that point for about $200 worth of product, you can install the mitigation system and have at least one cubicle that is properly constructed.

The benefits to this plan are numerous.

The facility sees the mitigation as a cost effective and viable solution.

The mystery and reluctance to mitigate goes away. Most people just don't know how easy and inexpensive mitigating is!

The flooring and adhesive specifications are met (which they are not when installed on a slab with no vapor retarder).

The problem is solved permanently.

You become the hero and your credibility and trust factors go up a notch.

In situations like this I throw in the mitigation for free. The cost is minimal. The experience is priceless. And remember, if you remove all that patch and replace it with FF, you still won't have a warranty from Ardex, the flooring maker, or the adhesive manufacturer. So if the problem comes back, you're in the same boat with less money, and now they feel it's your fault.

I'd give them the $200 worth of epoxy and see how it goes. Wink
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#7
One word of caution on applying a moisture barrier to part of a concrete slab. You may create a larger problem. The moisture comes up through the slab, hits the barrier, and starts moving sideways until it finds the end of the barrier. You could create moisture problems for the surrounding cubicles.

Based on your description, the amount of moisture here sounds minimal, so it may not be a problem. But I would hate to see someone read this and think it would work anywhere. I am working with a clinic in South Florida that is replacing thousands of dollars of linoleum because the flooring contractor did exactly what you describe.

Good luck on your project!
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#8
(05-22-2012, 06:19 PM)Matt S Wrote:  One word of caution on applying a moisture barrier to part of a concrete slab. You may create a larger problem. The moisture comes up through the slab, hits the barrier, and starts moving sideways until it finds the end of the barrier. You could create moisture problems for the surrounding cubicles.

Based on your description, the amount of moisture here sounds minimal, so it may not be a problem. But I would hate to see someone read this and think it would work anywhere. I am working with a clinic in South Florida that is replacing thousands of dollars of linoleum because the flooring contractor did exactly what you describe.

Good luck on your project!

Moisture doesn't move laterally through concrete.
JD Grafton
Concrete Answers for Flooring Problems
[email protected]
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#9
I am intrigued by your response. Could you elaborate? What prevents moisture from moving laterally in a concrete slab?

Matt S
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#10
Compare MVE to a pot of boiling water... steam does not move sideways as it rises out of the pot. Same principal. Moisture vapor emissions move straight up, yet CAN migrate latteraly to some degree. Therefore, I was trained to add a foor or two to the perimeter of any MM system installation similar to mine.

Update: I provided an estimate yesterday to the customer covering the "conservative" fix, vs. installation of a MM system. For about $700 more, they get a warranted fix. I suspect they will go with the system and be done with this problem.
JK Nixon
Concrete Restoration Services, LLC
Pittsburgh, PA
http://www.rhtester.com
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