We had prefinished hardwood flooring put in about 4 months ago. Gradually, over time, it is cupping. We have one place by the front door that it has actually buckled. The flooring acclimated in the house for at least a week before being installed. We had a company come out this week, and they said we have a humidity problem in our crawl space. He wants to incapsulate the crawl space and install a dehumidifier under the house. We have 2 more companies coming next week for a second opinion. We live in the Nashville area, where it is very humid. First question, could our installer have known that we would have this problem with the floors being installed early spring? 2nd question, why would the floors not be cupping underneath rugs. I did wait 30 days to put rugs down, as the installer suggested. Is the dehumidifier the best way to take care of this problem? Is there any chance that the cupping will go away after taking care of the moisture problem? Thanks for any help. I am sick about my floors.

Cupping is due a moisture problem beneath the flooring 99% of the time.

Acclimation has very little to do with thi s issue despite the technical info you may read.

The number one cause of cupping besides the obvious water damage/pipe break etc. is from an imbalance in subfloor moisture content to finish flooring moisture content.

The type of flooring, width, thickness will all be relevant.

Could a overly moist crawl space do it? it could.But it would have to be a significant change.

Could your installer know this? Not sure how to answer that for you.
Does he know this can happen.Probably?
should he assume it would happen in your home? Maybe?
If everything was fine at the time of install, how could he?


Cupping is tricky. I would start with the subfloors.

Buckling is always a direct water source, not just subtle humidity increases.

You are probably getting water under your front door or somewhere in the vicinity..

A simple moisture test will identify that.

I would agree w/ above - generally caused by water and/or moisture, and I would look for the source of this. Sometimes it's coming in from outside (and you mentioned worse by the door. Also, I would look to see if there are any appliances nearby. I've seen issues from refrigerators as well as laundry machines even though they were in another room and it has traveled thought the plywood beneath. Find the source and you should be able to solve.

The other note is that if this is solid hardwood, and it's 5" or more, it should have been nailed and glued. Also, there should have been sufficient space under baseboard/shoe molding. These items may have been done correctly, not sure.

Debbie Gartner aka The Flooring Girl
http://TheFlooringGirl.com
Westchester County, NY

Debbie and James,

Our flooring is pre-finished, 3/4" thick, and 3-1/4" wide planks. Debbie, what are you meaning when you say there should be sufficient space under shoe molding? Is there suppose to be a certain amount allowed for expansion? We don't thick we have any leaks, at least none we can see, and the cupping is everywhere. We also had flooring put in our upstairs hallway, and it seems to be ok. There could be water coming in at the front door, slightly, when raining. That's the only place that has buckled. One company that came this week said the RH in the crawlspace is about 80% and the RH inside the house is about 49%, and he did see some mold under the house. He thinks this is the cause. He wants to treat the mold, install a thicker vapor barrier, and install a crawlspace dehumidifier. Needless to say, it's a lot of money. Then, I guess we would see if the cupping corrected at all, and then see if we need to have the floors refinished. We're hoping the flooring company will help us with that...not really sure if they were at fault. Something else that the other company said is that the RH is higher coming out of our registers than it is going into the air return. He said it should be the opposite and he thought we should get our air conditioner checked out. The RH coming out of the registers was about 77% and the RH going into the air return was about 50%. We have 2 more companies coming out this week to give us a second opinion. Thanks, again, for any advice.

Thats 77% is almost as high as an evaporative cooler. First thing I'd do is check and see if your AC condensation line is clogged and leaking somewhere. I see this all the time out here in the southwest. Mine even does it (gets clogged with gunk). If it is you can simply hook up a shop ac to the overflow opening and suck it out, then reverse, blow it out see if that helps.

Im familiar with TN weather and I can tell you first hand that you have a poorly vented and or poor drainage (probably both) crawl space. Id also be willing to bet you live in a home with no front porch roof or awning with a uncovered little stoop leading to the front door. We had 20" of rain last month and have had more rain in three months than we normally do annually. Your floor's problem is the damp crawlspace keeps the floor wet on the bottom and your a/c is keeping it dry on top. Its the large difference of m/c above and below thats making the plank curl, the bottom is expanding faster than the top giving it a cupped appearance, balance it out (dry out the crawl space)and cross your fingers.

Update...we had the air conditioner guy out this week to look at our ac, and everything was ok. Kevin, you are right, describing our situation. Our front porch is not covered and we're sure a small amount of water has made the first tread going into the house buckle. We are looking into getting a storm door to correct that...need one anyway. You're also right about the rain. I'm not sure how many inches, but its been a lot. That being said, every company that has come to look at it, is surprised when it looks fairly dry under the house. There is no standing water, not even any on top of the plastic. When you pull back the plastic, there are a few areas where you can make a mud ball. The last guy that looked at it was really surprised about the floors. He did not feel good about telling us we needed anything done, because he said we had good drainage and he felt like it was not wet enough to warrant a dehumidifier...was afraid it would not correct the problem with the floors. Another company wants to put a curtain drain around 3 sides of our house(in the crawl space), that would drain out to the road. The 3rd company wants to encapsulate the crawl space and install a dehumidifier. We just want to make sure we do the right thing. Are any of you familiar with hiring a certified wood flooring inspector through the NWFA to find out what the problem? I think it would cost about $500. We just want to make sure we do the right thing the first time. Thanks for any advice. You guys are great!

One other thing I forgot to mention is that we also had flooring laid in our hallway upstairs, and we are not having any problems with it.

the floor upstairs isn't cupping because its a conditioned space above and below the floor keeping it balanced and flat. I personally would look up Wayne Lee with Cardinal Hardwood. He now works for Middle tn Lumber in Burns,Tn. He knows more about wood floor installations than most people in the country. He is also certified by the nwfa. ID say your about right on the fee, 500-600 is what I have paid in the past for certified inspections. He will know how to track down the source of the problem and give you actual readings of the moisture content of the floor, the subfloor both above and below. Without quantitative measurements you just playing a guessing game.

Kevin,

Thanks for the info about Wayne. Do you know how I can contact him? I tried calling Middle TN Lumber, but they were already closed. I also checked the NWFA website, and I don't see him listed on there. I may have to wait until Monday to call. Appreciate your help, Kevin!

There is only one definitive way to assess this and that is to have moisture readings of the top of the wood, the back of the wood and the subfloor. Recently inspected one in El Paso TX parquet down many year buckled all over the house. Removing a few pieces the rh readings of the concrete were 2% not unusual in El Paso. The wood was around 9% on average. Eliminating the subfloor that only left the RH of the rooms which were at 65% way too high and the only other thing that could have caused it. Parquet was installed using black mastic and only about 45% coverage. This floor had been down many years but the high levels of RH in the home was the only possible cause left after eliminating other possibilities. There are only three possibilities 1. excess moisture in the subfloor. 2. Excess moisture in the air. 3. Flooding the floor.