Get a plumber with a moisture meter who is used to hunting leaks in a slab. If that’s it, it should be easy to find. If that’s not it, and it’s a standard humidity and concrete issue, then forget about it. That isn’t horrible, and with the furniture in the room, is likely barely noticeable. In 7-10 years when it’s time to do something else with the floors, do something else.

Thank you GreenDesign but if it is just naturally occurring moisture, couldn't mold grow under the floor? Honestly, the way it looks is of no concern to me BUT I do care very much about my health and well-being. Maybe Floridians hyper sensitive to mold and that scenario is unlikely?

If they used Bostiks MVP, "a flexible, rubber like consistency" they covered the bases for sure.

Forget a general contractor. They'll just hire others. Start with the flooring company. They should respond in good gesture and possibly offer good clues as to the cause(s)

Mold grows in dark and damp conditions. Very doubtful a plumber would have the proper moisture meters.

Uptown Floors, thanks, I feel a little better that they tried to take the right precautions even if it didn't work. I'll give them a call and see what they say. He did indeed use Bostik and if that product covers all the bases, then I'm surely concerned.

If a plumber doesn't have proper moisture meters, how/who determines if there's a leaky pipe under the slab?

" Since the likely culprit is moisture"

You're getting ahead of yourself. You have a floor that shouldn't be overly affected by moisture ("Exclusive to Floor & Decor, NuCore® is 100% waterproof flooring"), sitting atop Bostik MVP, an excellent moisture barrier product. Jumping to the conclusion that the likely culprit is moisture seems illogical.

If it's pretty uniform all over, it's unlikely to be caused by a broken pipe under the slab (and under the MVP). If it's from another unidentified leak on top of the slab, you should have other signs of moisture present. Since you don't mention any, I assume they don't exist.

Call your installer first. I don't know what your arrangement was in regards to who bought the flooring, but if it's a material issue, that party will have to pursue it with the supplier.

You'll likely need to hire an inspector if you want to get to the bottom of this. I'd start at: http://www.ifcii.org/ . They will likely ask questions about acclimation and whether you have proper transitions and expansion space.

Or you could do what Jan Moyer suggested, which could make sense since you didn't notice the issue until you moved the furniture. If you go that route it would be interesting to remove a plank in a closet to see if there's any evidence of moisture.

I'm going to throw my hat into the ring. The vinyl plank has a CORK BACKING. Cork is wood. Cork bark (not ground up stuff) is almost impervious to moisture...almost. But the GROUND UP stuff (the crumbly bit on the back of the planks) is not. I'm going to bet the moisture has reached the cork backing and the cork has expanded...every grain of cork has puffed by 1% or so...which mean it is now much BIGGER than the vinyl it is attached to. When the bottom of the plank puffs MORE than the TOP you get cupping....just like you see in your photos.

Just like normal wood, a cork-backed vinyl plank will show the direction of the moisture. If you imagine the centre of the plank as an arrow head, it will point you in the direction of the moisture. The centre of the plank is sitting lower than the edges...and therefore is pointing DOWN. The moisture is greater underneath.

I personally would pull up a small section (pick a room) and investigate the subfloor below. See if the moisture barrier is still in place....if it is peeling/bubbling, etc. These basic roll-on topical applications can be overwhelmed. Despite their claims of 100% vapour barrier, they may not be tough enough to be a MOISTURE barrier (vapour = airborne water: moisture = visible/running water).

The next thing I would check is the INTERIOR HUMIDITY levels. It is possible, the indoor air humidity is too high. You will need to maintain it around 35%. If the roll-on product is still intact it is possible you can correct this cupping by DROPPING the humidity levels.

Because cork is the only product on this plank that can expand in the presence of moisture, I'm putting my money on the cork being the culprit...but always check your expansion gaps and your transition strips through ALL doorways.

Where I live in southwest FLA, the humidity in the house is always high for the most part except in December and January. It's why I selected porcelain tile for the floor. If you have your doors and windows open any length of time you have to purchase outdoor ceiling fans for indoor rooms or your blades will sag

Someone that doesn’t think vinyl expands or contracts has no experience with vinyl.Look at a badly done vinyl sided house for primary facia evidence. Gaps everywhere in the winter, and buckles in the summer. It moves more than wood does due to temperature changes. It’s why you can’t have it in front of a big sunny window without it buckling.

Climate control with vinyl vinyl floors is more critical than it is with wood.

SJ, I think you're mostly right and I knew that already but sometimes when others concur it helps lead the way. I do disagree on a a few things though ... 35% indoor humidity is almost impossible to maintain in Florida. Even friends with brand new homes and far more modern HVAC systems experience higher than that. Surprisingly, for the age and its modesty, my condo is on the dry side because I never open windows or doors and run the AC virtually 24/7. Also, the barrier wasn't a roll-on but a trowel application and pretty thick. From what I've learned since, it is considered a better application. I was lead to believe it was the best option but like I said, this is not about blame. If it failed, I just want to know what won't. And when I bought the vinyl, they lauded the cork back as an anti-microbial which sold me on it.

Beverly, you're right. I should have gotten tile but I'm so sick of it and it's so permanent. It took me a few weeks to drill it off the original floors (so the moisture level certainly wasn't affecting it) but since the vinyl floor was installed, the stairs have also been renovated (it's a fixer-upper) and I think a thick tile on the floor would adversely affect the incline/height of the first step so I feel that fixing/understanding what is happening is best. Hindsight is 20/20, right?

I'm going to call the flooring company or a different one and see what is happening as soon as the drywall work is done -- the electrician left quite a wake! I don't like not knowing. I'm not too worried about mold but it is something to always consider in Florida.

I'm actually very surprised by your comment Jan. You're not usually so laissez-faire but I do indeed, hope you're right!!

Thank you all.

Laissez - faire and reality are very different. : ) It's ALL over , not a huge issue in one spot. Buy a big de humidifier, or rent one. Bet me it goes to nearly flat.

As a really good contractor said to me: "We stick to tile on main floors here, or we make them sign their lives away.........."

I am wondering (for my own information) if expansion room is needed for your type of f!oor. It definitely is here in the midwest. Not enough room for expansion will cause cupping.

erinsean, thanks! When it was installed, they left a gap for expansion but those instructions are always right on the box for any flooring. I read the whole box when he indicated the natural moisture level was too high and told me I should apply the vapor barrier. I wanted to know for myself. If you're considering a specific flooring, read the box. I would imagine most people don't.

Good to know. Guess our installer knew what he was doing. You have a pretty floor.

You will need to talk to your floor installer. Ask them if, they prepared the subfloor before applying the MVP. Any contamination that was not removed would act as a bond breaker - causing adhesion issue. It is not something that would be noticed within the next day. It usually takes a few days of curing, before the products starts to become loose and pull away from the subfloor. Installation is usually completed by then.

It is the same type of issue with leveler, when sealers and contaminants are not sanded or grounded off. The product does not have a good bond and fails.

Is this a click together or a glue down floor?

And the installer used plastic sheeting (6mil or 10mil vapour barrier properly taped at the seams) underneath? And all TRANSITION strips used at ALL doorways? And expansion gaps at the walls/door jams are 1/2" or more?

MVP is rated for unlimited vapor protection. But your flooring indicates moisture issue. It is either the product or the installation. I would question the installation First. Was the slab grind And free of contamination? Was the trowel replace as needed to ensure proper coverage? Was the correct size trowel used? If, all these questions pass. Then you will need to contact bostik for tech support.

You know, it's funny you say that because the slab was prepped for the MVP as I originally hired the flooring company to only prep the floor for installation and I was going to install the floor myself but after drilling all the tile up and the discovery of the moisture, I let them do the whole thing. The installer took a photo of the new trowel with the bucket, my name on a card and I think the moisture reading and he used a new trowel with every bucket he opened and photographed those. I remember because I thought wow, I hope this works, he's really covering his butt.

And here we are! ;-)

Transition strips are required for ALL floating flooring....not just LVP with cork backing. All floating floors need to have the ability to 'move'. A hardwood floating floor needs them. A cork floating floor needs them. A laminate floating floor needs them. A linoleum floating floor needs them and a vinyl floating floor needs them. The question becomes HOW OFTEN do you need them.

I have a massive problem with the Floor & Decor website with the installation suggestions. They state that you can install up to 6400sf without transitions. I have to call BS on this one. The reason: cork.

Cork is EXTREMELY dynamic. It REALLY LIKES to stretch its legs. In fact a cork floating floor can expand as much as 1" over 25 linear feet. That is HUGE! MASSIVE! Almost unheard of. So...are the transition strips "really necessary"? With cork, yes. With vinyl, no. With cork+vinyl, yes.

Floor & Decor has used the "click edge" documents (the fastening system) without taking into consideration the dynamic nature of cork. The 6400sf of continuous install is fine with an SPC core and the edge system. But the technical data becomes useless as soon as you add in vinyl and cork together.

I would pop off a baseboard (somewhere) and look to see if your expansion gap has been maintained (I want to see 5/8" or more). If the floor has pushed itself up to the drywall, then you know you have a problem that can be fixed with transition strips.

The easiest fix *might be to cut the floor at all door jams and drop in a low-profile t-moulding. As annoying as this is, it could the be the simplest fix. But first the moisture source needs to be addressed.

I still think the Bostik has been overwhelmed and I think the cork has grabbed the moisture and pushed everything to the absolute limits (ie. the walls).

Our flooring did that after less than a year. The manufacturer refused to address it. We used underlayment/moisture barrier. The problem is that when it cups, the edges become brittle and break off in strips, resulting in sharp edges. We laid rugs where we could but some places are not appropriate for rugs. We are riding it out until we save enough to have a poured floor or ceramic installed. Yes, we used a professional flooring installer. Normally we would have done it ourselves but because we were under a time crunch we hired the work out.

Hi Joe;

I have a similar experience, a difficult retailer and a case in small claims. JOE: Did you ever find out the ultimate cause behind the cupping?

If, it's vynil flooring. You may want to keep a look out for expansion between seasons. Then make your fixes. Heat will cause vynil to expand.