Thread: Cupping floor

Forth floor of twelve story Chicago masonry condo built 1997. Year old floor measures 13-15% throughout. Flooring was laid over 3/4 plywood sub floor over concrete slab after "acclimating" on loading dock. Don't know what type of vapor barrier. Portions of the floor are cupping, other portions not displaying much cupping are lifting sufficiently to deform kitchen cabinets frames enough that drawers won't close, at other end end of unit entire floor in hallway is crowning sufficiently so that bedroom door won't close. There are cupping sections of flouring throughout. Wost areas are right in from of a ventless gas fireplace.

My question is this: I've never seen this happen to this extent without some sections of flooring visibly buckling, instead in this case the floor as a whole has remained reasonably flat, but individual planks appear to have expanded with such force that wood fibers or wood filler (can't tell which) are being forced out between them like toothpaste from a tube.

I realize that this needs to be deferred to a flooring contractor, but I'm curious for my own knowledge: what's happening here? Am I possibly looking at flooring adhered rather than nailed to the sub flooring, and sections of sub flooring crowning under the cabinets and doors, and taking the flooring along for the ride?

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Originally Posted by Michael Thomas

Flooring was laid over 3/4 plywood sub floor over concrete slab after "acclimating" on loading dock.

Looks like engineered wood with real wood top ply.

That stuff geeing squeezed out, does it look like 'glue' or 'wood filler'

Nailed/stapled down, glued down, or floating?

Don't know what type of vapor barrier.

Or if there even is one.

Portions of the floor are cupping, other portions not displaying much cupping are lifting sufficiently to deform kitchen cabinets frames enough that drawers won't close, at other end end of unit entire floor in hallway is crowning sufficiently so that bedroom door won't close. There are cupping sections of flouring throughout. Wost areas are right in from of a ventless gas fireplace.[/quote]

Insufficient gap left around the flooring at the perimeter base. The moisture (for the concrete slab or from inside the unit) has caused the floor to expand, pushing the flooring against the sides (at the base), causing the center areas to tent (like tile does when it tents).

My question is this: I've never seen this happen to this extent without some sections of flooring visibly buckling, instead in this case the floor as a whole has remained reasonably flat, but individual planks appear to have expanded with such force that wood fibers or wood filler (can't tell which) are being forced out between them like toothpaste from a tube.

Answers my question about what is being squeezed out - probably filler, the wood fibers would look different than "like toothpaste from a tube".

I realize that this needs to be deferred to a flooring contractor, but I'm curious for my own knowledge: what's happening here? Am I possibly looking at flooring adhered rather than nailed to the sub flooring, and sections of sub flooring crowning under the cabinets and doors, and taking the flooring along for the ride?

Short of removing the flooring and replacing it, you might (with that being a *big might*) be able to cover the flooring with plastic sheeting, tape the plastic sheeting down, insert the tube end of a dehumidifier into the plastic sheeting and see if you can 'suck the moisture out of the flooring'.

If it works, that has not solved the problem, only identified as to what happened, not why it happened.

Before doing that, though, I would remove a few sections of shoe molding and base, checking for the required gap - my guess is that you will not find a gap.

Might not even find a moisture barrier under it (that's what I'm suspecting), or at least one which was insufficient/inadequate, violated all over with holes, not taped at the joints, etc.,

Thanks,

Those are pretty much the issues I've discussed with the client.

When the flooring was left to acclimate at the loading dock, perhaps it acclimated just a wee bit much. The wood could have been overdried sitting out in the sunlight for who knows how long.
Once it was brought indoors and installed, like Jerry said, with tight edges, it once again began to suck moisture in, expanding.
Wood flooring laid over concrete, even with 3/4 ply sub-floor, will need a vapor barrier. There are special mastics for applying wood flooring directly to concrete surfaces that have a sealer in them in order to keep moisture from reaching the flooring.
I also wonder what the humidity factor is in the unit below that one.

Cupping is a sign of moisture from the underside.

Originally Posted by Scott Patterson

Cupping is a sign of moisture from the underside.

.

Looks like water damage ( with water trapped beneath the flooring & sud flooring. )

WH or other plumbing leak as the cause.

It all has to be removed.
.

Michael--
You state: "Year old floor measures 13-15% throughout. Flooring was laid over 3/4 plywood sub floor over concrete slab after "acclimating" on loading dock."

I have a question. Was the plywood in place PRIOR to the installation of the wood? I can't see why it would be there (over concrete) unless there was a previous flooring material that needed it. If the plywood is new, maybe it had ridiculous amounts of moisture in it prior to installation.

In any case, It is clearly a moisture issue. 13-15% !!!?? Sounds like about twice what it should be. Perhaps the owners mop with a really wet mop assuming that the floor is "waterproof" since it has a couple coats on it. Some people really are clueless...or their maids are. (Yeah, I've seen it.)

If the damage is not uniform across the entire floor, there may be some localized seepage, such as from the dishwasher. Since there is a concrete slab under this, any leaks would presumably hit the slab and spread laterally through the underlayment.

Maybe the automatic fire sprinklers went off at some point...

Originally Posted by Scott Patterson

Cupping is a sign of moisture from the underside.

Not necessarily.

The top of the flooring is finished, no moisture gets in or out (basically speaking).

The sides and bottom are not sealed at all.

Water (moisture) getting into the tongue and grooves, as well as water (moisture) getting in from underneath will all cause the same thing - the top surface tries to remain the same dimension and the bottom parts get bigger.

Doing what the Swiffer (spelling) commercials on TV show doing with a wood floor (wet mopping it) is the worst thing you can do to a wood floor. Using a 'dampened' mop works because you are only wiping across the surface with the 'dampened' mop, not actually dumping or squirting water onto the floor as they show in those commercials.

I would love for someone what did what they show to sue the Swiffer butts off - replace my floor, by the way, it is Brazilian mahogany with teak inlays. 25,000 square feet of it.

Jerry,

It's been a long time since we chatted. You helped my out with a metal roof concern once; thanks for that. I'm curious, you made this recommendation here "Short of removing the flooring and replacing it, you might (with that being a *big might*) be able to cover the flooring with plastic sheeting, tape the plastic sheeting down, insert the tube end of a dehumidifier into the plastic sheeting and see if you can 'suck the moisture out of the flooring'."

What type of dehumidifer are you refering to?

The possibility of a water leak is the reason I was there. I did not have access to the occupied units above or below this one, and I did not perform any destructive investigation beyond the insertion of the meter's pins. There was no evidence of a current or previously active leak in any of the likely locations served by supply or drain plumbing or at typical entry points from the exterior, or related to HVAC (central chiller system with air handler remote from the unit). It could be the case that there is an inaccessible leak, but if so it is is causing a very uniform level of moisture throughout the entire unit, and in every case where I've seen this kind of leak there is at least some moisture gradient between the source of the leak and locations remote from it.

-----------------

This condo's flooring has a rather complicated history. Per the unit owner:

1) Floor was laid.

2) Installer created leak in ice maker supply line, extensive floor damage to kitchen and living room on other side of wall behind refrigerator resulted.

3) The flooring in the kitchen and much of the rest of the unit was removed.

4) The installers the replacement flooring monitored the moisture level in the slab with some type of meter, and waited until the moisture level had stabilized.

5) The new flooring sat on an interior loading dock over a weekend, and was then installed without a further wait for acclimatization.

6) Over the next several months, progressive cupping of the floor was observed in several areas. (I did not measure significantly greater moisture content in the flooring that was cupping compared to flooring which was not).

---------------

Per the owner (an intelligent and observant woman) a vapor barrier composed of a black material rolled out onto the floor in strips was placed over the concrete floor slab, and what from her description appears to been 3/4" plywood subflooring (in this area at least that's a standard substrate for hardwood flooring instaled above grade when installed over six mill poly sheet):




was installed above the vapor barrier or waterproofing material. The client did not observe how the subflooring was attached to the concrete slab or whether the floor was stapled or nailed to the subflooring.

So at this point there are a lot of possible installation defects that could create the sort of defects I was observing without a point source leak to introduce moisture from within the unit itself.

Clearly, the next step is going to be to open up a portion of the floor and find out what's actually down there, this one looks like it's probably headed for court, so I'll be recommending that the destructive investigation be performed by a local guy who's a NOFMA certified wood flooring inspector, if I have a chance I'll try and run by this condo (it's close by) when he does the investigation, and I'll take some pictures of what's found post them.

Ironically, a buddy of mine who moved to Chicago had this same problem in a condo he had under contract. It was the 14th floor of a new high-rise, and before he even closed on the unit, he had issues with the hardwood floor cupping and buckling. He complained..the builder said it was "normal adjustment." I told him that was complete horse hockey. He pursued it, and it turned out that the builder hadn't run the condenstate drain line for the HVAC unit to any type of drain. It was just draining onto the slab.

This same problem was impacting numerous other units in the building. My friend threatened a lawsuit and got out with this deposit. Thank goodness he didn't trust the builder and move in expecting the problem to fix itself.

Of course, this was a NEW unit and not several years old. Have no idea who the builder was, but makes me wonder if it's the same guy as these folks have.

Originally Posted by John Badger

What type of dehumidifier are you refering to?

John,

Essentially a 'portable ac unit'. Which is nothing but a dehumidifier using the cool air for conditioning.

Some portable ac units have supply grills and flexible duct which are placed out the windows, others have flexible ducts on both sides (or maybe the user at the places I've seen them made their own second duct set up for flexibility?). Place the flexible duct (the tube) into the sealed plastic sheeting area. It will suck moisture (dehumidify) the floor and the slab.

Originally Posted by Michael Thomas

The possibility of a water leak is the reason I was there.

Michael,

Ha-ha, now you tell us.

I see several thing wrong (not done correctly) in your description of what has gone on before.

First, most flooring is manufactured at 6%-9% moisture content. While 13%-15% is not high, it is double what it was manufactured at.

This condo's flooring has a rather complicated history. Per the unit owner:

4) The installers the replacement flooring monitored the moisture level in the slab with some type of meter, and waited until the moisture level had stabilized.

Sounds like they did not monitor the moisture content in the slab correctly. If they had done the 'tape plastic to the floor for two days and check for moisture test', she would have seen that and said so. That is the best way to check for moisture in a concrete slab.

5) The new flooring sat on an interior loading dock over a weekend, and was then installed without a further wait for acclimatization.

Not good.

That flooring should have been allowed to acclimate to the air within the unit it was being installed in. Years ago (with plank flooring) I remember the recommend acclimation time was 2 weeks. many solid pre-finished floors are now only 3 days, with engineered wood having been reduced to 2 days. You would need to check the installation instructions for those requirements - but they will likely be close to what I stated.

6) Over the next several months, progressive cupping of the floor was observed in several areas. (I did not measure significantly greater moisture content in the flooring that was cupping compared to flooring which was not).

Sounds like it started shortly after the flooring was installed, and kept getting worse.

Per the owner (an intelligent and observant woman) a vapor barrier composed of a black material rolled out onto the floor in strips was placed over the concrete floor slab,

I suspect that if it had been black plastic sheeting, she would have called it plastic sheeting. With her calling it a black material, I would guess it was only 15 or 30 pound felt. Felt is a vapor retarder, not a vapor barrier. Basically all the moisture in that slab is going to get through the felt eventually.

and what from her description appears to been 3/4" plywood subflooring

Okay, question: Was the plywood removed when the flooring was removed? If not, all the water which leaked out previously is now in the plywood, which is now in the wood. *ALL* the plywood would either have had to have been dried in some manner down to 14% or less moisture content or have been replaced. If not, then the moisture is on top of the moisture retarder (which should have been a moisture barrier).

(in this area at least that's a standard substrate for hardwood flooring installed above grade when installed over six mill poly sheet):

And all the repairing installer did was to roll out some type of black material - possibly 30# felt.

was installed above the vapor barrier or waterproofing material.

Or vapor retarder.

So at this point there are a lot of possible installation defects that could create the sort of defects I was observing without a point source leak to introduce moisture from within the unit itself.

Exactly.

Clearly, the next step is going to be to open up a portion of the floor and find out what's actually down there, this one looks like it's probably headed for court, so I'll be recommending that the destructive investigation be performed by a local guy who's a NOFMA certified wood flooring inspector,

Use caution in relying on those guys. I am working on one now (which has hollow areas under the wood, indicating unbonded areas - glued down floor on slab) in which the certified wood flooring inspector stated that the hollow area in the wood flooring "are well within the tolerance limits allowed by the manufacturer", so I call the manufacturer and they emphatically stated "If the sub floor meets our requirements for flatness, moisture content, and structural soundness; if the adhesive was applied properly as specified; and if the wood flooring was laid as specified - *there will be no hollow areas* ... thus *we do not have an allowed tolerance for* "hollow areas".

Sure shoots that NOFMA certified flooring inspector in the foot, doesn't it. He was hired by the supplier who installed the wood flooring for the builder. Think there was any pressure on him to outright lie and state it was okay?

Originally Posted by Jerry Peck

Not necessarily.

The top of the flooring is finished, no moisture gets in or out (basically speaking).

The sides and bottom are not sealed at all.

Water (moisture) getting into the tongue and grooves, as well as water (moisture) getting in from underneath will all cause the same thing - the top surface tries to remain the same dimension and the bottom parts get bigger.

Doing what the Swiffer (spelling) commercials on TV show doing with a wood floor (wet mopping it) is the worst thing you can do to a wood floor. Using a 'dampened' mop works because you are only wiping across the surface with the 'dampened' mop, not actually dumping or squirting water onto the floor as they show in those commercials.

I would love for someone what did what they show to sue the Swiffer butts off - replace my floor, by the way, it is Brazilian mahogany with teak inlays. 25,000 square feet of it.

When you have moisture from the top as in mopping this will cause the wood to bow or bridge. I have seen this many, many times. moisture or Water from the underside will cause it to cup.

Yes, I'm sure it is possible that this is not always the case. But, when you are looking at a cupped wood floor the first thing you should look for is moisture under the flooring.

I agree that the top coat of finish does have some bearing on the way the wood react to moisture. I just have not seen wood flooring react that way in about 99% of the floors I have looked at.

Then we have the manufactured wood and the solid wood flooring product that both react differently.

Originally Posted by Scott Patterson

When you have moisture from the top as in mopping this will cause the wood to bow or bridge. I have seen this many, many times.

Scott,

I suspect you are referring to older floors where the finish is wearing.

On newer floors, the finish will puddle the water, not allowing the water to soak into the top, causing the water to run down over the sides of the wood flooring, creating the effect of moisture from below.

Yes, I agree with you, on older wood floors where the finish is not that of a manufactured finished or is wearing away, the water will penetrate down through the top, causing the bowing or bridging you are referring to. I have seen that too ... on older floors.

But this is basically an newer floor, with the newer manufactured finishes.

ventless gas fireplaces(illegal here) produce large amounts of moisture in the units?????

Originally Posted by Jerry Peck

Use caution in relying on those guys. I am working on one now (which has hollow areas under the wood, indicating unbonded areas - glued down floor on slab) in which the certified wood flooring inspector stated that the hollow area in the wood flooring "are well within the tolerance limits allowed by the manufacturer", so I call the manufacturer and they emphatically stated "It the sub floor meets our requirements for flatness, moisture content, and structural soundness; if the adhesive was applied properly as specified; and if the wood flooring was laid as specified - *there will be no hollow areas* ... thus *we do not have an allowed tolerance for* "hollow areas".

Sure shoots that NOFMA certified flooring inspector in the foot, doesn't it. He was hired by the supplier who installed the wood flooring for the builder. Think there was any pressure on him to outright lie and state it was okay?

I've not used the the local NOFMA certified flooring inspector (John Dailey, based out of Wheaton, IL ) before, but he has a good rep and seemed on the level during a phone discussion of this floor. We are going to coordinate our schedules so that I can attend his inspection, and I'll post my impressions.

----------

Speaking of water problems, we had around 7 inches of rain last weekend before last, found this little beauty this afternoon below a missing parapet flashing in three year old construction:

Originally Posted by Michael Thomas

I've not used the the local NOFMA certified flooring inspector (John Dailey, based out of Wheaton, IL ) before, but he has a good rep and seemed on the level during a phone discussion of this floor. We are going to coordinate our schedules so that I can attend his inspection, and I'll post my impressions.

----------

Speaking of water problems, we had around 7 inches of rain last weekend before last, found this little beauty this afternoon below a missing parapet flashing in three year old construction:

Those are great in a stir fry!

Here's what the local IH I recommend (Brian Bussy at Bussy Environmental Services, Bussey Environmental, Inc. Home Page) had to say about those pics:

"I have run into this exact occurance on multiple occations. Due to the missing parapet flashing above this location and the recent extreme rain events (ie Sept. 13 area experienced over 7 " of rain - 100 year rain event); this area above has become damp enought to support this type of mushroom growth. Looks like a wood ear type mushroom. The times in the past when I removed the ceiling In these areas of growth, these mushrooms generally have a long wood like stem that can travel several feet to where the soft wet wood is associated with the exterior defect that is allowing a locallized area of wood to become very wet and originate such growth. It usually looks more horifying than the area of soft and wet wood above and doesn't always relate to a large area of damage and can usually be restored if the roof defect is fixed, the area above the ceiling is accessed, cleaned and wet or rotted wood cleaned and dryed or replaced; drywall removed and affected insulation replaced and repaired. "