You might want to ask this question on the flooring forum too where flooring experts hang out.

Also what underlayment was used between the cement and the hardwood flooring?

I don't think that cupping reverses.

Cupping is caused by the wood drying out/absorbing moisture unevenly.

Do you know any of the installation details? The moisture readings of the floor should have been done BEFORE the flooring went in.

What sort of barrier do you have on the concrete floor? My understasnding is typically hardwood is NOT recommended over concrete, whereas engineered hardwood is recommended. This is because concrete, ESPECIALLY new concrete, continues to transmit and release moisture as it cures.

If they were to resand it flat, and restain/reseal it, you may still have the same issue - if the wood has uneven moisture levels top to bottom, it will dry unevenly and cup again.

Also, what width are your planks? The wider the plank, the more prone to cupping...it's one of the many reasons narrow plank was used in the past.

cpartist I did list this under design dilemma and flooring, hoping to get feedback from flooring professionals and anyone that may have actually had this condition correct itself.

Our crawlspace was built as what was referred to as a ' conditioned crawlspace' with a concrete floor, walls, and piers because we did not want moisture issues. Our subfloor is the typical construction with OSB, etc. and I did see a black paper or film of some sort being applied under the hardwood before it was completed and sanded.

loohintomyeyes83 I think I may have not been clear about our subfloor. See my above post. The subfloor is not on concrete. The crawl is sort of a mini basement encapsulated by concrete so no ground moisture is present. I do understand that the RH and moisture content of the wood need to be maintained at certain levels.

The planks are of varying, random widths and some of the wider planks do not show cupping.

The installer provided proof that the moisture content of the wood and the subfloor was within the acceptable range of around 6% when the flooring was installed. The floors are now at between 9-10%, which our installer said is due to lack of HVAC for over two months to remove moisture from the home.

I'm not a flooring expert, but in my previous new construction house that was built over an unconditioned crawl space, we had this problem in a very small area. When we moved in, our pre-finished hardwood floors looked fine. A year later, I installed central air conditioning. That's when a small portion of flooring in our kitchen started cupping. It really stressed me out but luckily, the builder's customer service rep had the flooring company owner stop by and check it out. They measured the moisture under the crawl space and in the house and they were "normal", whatever that means. They told me to wait until February (this was around April/May of the previous year) to call them if that area was still cupped. Sure enough, the cupping stayed throughout the summer but once winter came, the cupping disappeared. We lived there for another year or so and the cupping never came back.

Your builder’s failure to provide proper HVAC is the primary current offender. But the semi conditioned crawlspace could also be a major culprit if that was not created properly.

This goes beyond a “flooring issue” and into the design details of the home construction. Did your architect provide construction oversight services during the build? Someone independent of the builder and skilled in whole home systems design is what is needed here.

You’re looking for a simple answer and there isn’t one. Moisture in a home is a complex interaction involving a lot more than the end floor covering.

You need a local on site experienced Professional. I might start with an Energy Rater and testing to assess air leakage and moisture leakage into the home. After going back and assessing the details of the short basement issue. Once you have an idea of how moisture and air is moving through the home, you can address the symptom of the bigger problem. Which is your wood floors.

The crawlspace is where I would focus dehumidifier and humidity monitoring efforts. Good job on going unvented! You need to get a covering over the access and ensure the hvac system is conditioning the area close to the house conditions.

Ditto what Sophie said. Concrete by itself is generally not a moisture barrier. Airsealing at the masonry to wood transitions will help prevent unwanted moisture transport.

We are going to take readings daily and document our findings. I don't know how much time is needed to insure that conditions are proper and have stabilized within acceptable levels. What is an acceptable time frame for this?

If we see RH maintained between 30-40% and wood moisture go down and stay between 6-7% for a week or so, should we expect the cupping to reverse and stay flat as long as those conditions are maintained?

It can take months for wood to go back flat. Not weeks. But it never will if that short basement isn’t constructed properly.

You are focused on the symptom and not the problem.

We will of course look closely at the crawl. We do not want a repeat problem. There was minimal oversight on the build, which is approaching 13 months, but I am hoping there is no issue there. My questions are posed with the assumption that the crawl conditions are okay and that all conditions related to moisture are reversed and managed.

IF there is good reason to believe this issue will reverse over months given proper and constant conditions, then we would be inclined to move in. We did not want to demand the floors be replaced if every condition has been met and the consensus is that it will remedy itself. We DO NOT however, feel that we should accept these floors or have to have them sanded in several months to resolve this issue. None of this is our fault. Our builder is liable. We have not closed on the home yet. We just want to be fair and reasonable but get what we paid for which is perfect hardwood!

It may or may not resolve. Even fully insulated basements can emit enough moisture to cause this, well after the humidity above is prefect and stable. Frankly, I'd have used an ENGINEERED floor in this situation. Sealed crawl space or not. Even that should sit for a couple weeks in the conditions that represent an installed state, before installing.

I recently had a client who would not listen and delay flooring to post paint in a big reno. Her painters ( idiotic!!!!!!) practice of sealing every inch of the house in prep, and my warning went unheeded. MOST ridiculous thing i have seen and had to be 6k in blue tape and plastic to prep. Every window, every light switch. Hot outside and no AC on, it was like a greenhouse. ! He SPRAYS. Yes, sprays. What's in paint? Water!! LOTS of water Her much agonized over, sand on site floors still have not completely flattened, though they are far better and she decided not to focus on it. They are far better on the second flor than the first floor, so what does that say? This despite monstrous de humidifiers running full time.

Yours may, and may not. It IS complex. Be prepared to wait, it won't resolve by move in.

"Minimal oversight on the build"??? This may be the LEAST of your problems my dear. Where were you or the designated person in charge of "oversight"?

We had a cupping problem with our new install floors and we had a full basement and a sophisticated heating/cooling/humidistat system. We live in a very moist area, year ‘round.

I should have chosen engineered floors and not hardwood. But, I didn’t know any better. The floors did settle down once the house was up and running, but I never opened my windows if humidity was even low.

Jan Moyer our production manager, foreman, lead man......whatever you want to call him laughed in my face when I said that we had expected him or someone from his company to be on our site daily or nearly daily to insure subs were there working, installing the correct products, securing the sight, performing quality work, and cleaning up at the end of the day. He said that was impossible and would never happen. I have been there several days a week to catch many mistakes. So many things have had to be done over.

We went in the crawl today and took a very close look. Everything is dry and sealed. The walls are insulated with styrofoam although some are coming unglued. The sump pump is not sealed and no crawl hatch door is installed. We tested the moisture of the main beams and subfloor which measured 10-12%. The moisture content of the floors is averaging around 8.3% so it is slowly drying out.

We have talked to the owner of the company and he says that he is committed to resolving problems to our complete satisfaction. We'll see. I appreciate all of the input here and hope it not only benefits us, but others as well.

If the floor was installed in the wrong conditions, sanded in the wrong conditions, and finished in the wrong conditions, then it is unlikely that they will lie down, unfortunately. Have you considered getting in touch with an actual NWFA inspector to come look at the floor? Could you share photos?

Your contractor should have had the HVAC installed and working before and the wood in the heated/cooled house for at least two weeks before installing the floor.

This may not be the best pic, if you can zoom it shows a bit better. All floors in every room are cupped. We will involve an inspector if needed, but there seems to be little doubt where the responsibility lies. We are meeting with our builder this afternoon on other issues as well. As much as we hate to, we are leaning towards replacement. Makes me sick.

Replace it and don't let them talk you into anything less than that. Back in early marriage when I was watching This Old House, I learned that show that you had to let wood flooring acclimate before it was laid.

Acclimation is an incredibly important step when installing your expensive new floors. Carolina Kitchen & Bath is correct, you should definitely hold them accountable for rushing your installation. They knew the risks. There is no excuse to ever install flooring until the house has been appropriately heated and cooled for a week or two. In most situations, the floors should be the absolutely last thing done before moving in, paint included.

http://www.shannonwaterman.com/blog-headlines/blogart20

Our movein was moved up about 2 weeks while the flooring people waited for the wood flooring to acclimate. They tested it every couple of days until the moisture in the wood was at the correct percent. We have been in over 2 years and the wood floor is still perfect.

SEE UPDATED POST FURTHER DOWN........Well, as painful as it is to delay moving in even longer, we have decided to have the flooring replaced. It's really the only option that's fair to us. In the meantime we will have time to make sure there are no leaks, etc. before the new floors go in. Thank you all so very much for taking the time to offer your opinions, experience, and advice. When a good friend asked the question " Ask your builder if he would accept this for his family" , I knew he was right. If it's not good enough for your family, it shouldn't be good enough for your client. Thanks again and Merry Christmas.

Sorry you're having to go through this but it's the right thing to do and you'll be glad you did in the long run.

You're ripping anyway. Might be worth a go at a total RE SAND asap. Let it sit a week. UNFINISHED and raw.. Come back and see. .......might cut the time in half., and not much to lose in the attempt? At this point, what have you got to lose? And a nice big credit to boot for the inconvenience and the delay. Sorry for your plight.

Jan, my last post was premature. My builder is now refusing to replace the floors and expects us to take the ' wait and see' approach. He says they will lie down in a few months, and if they don't he will have them re-sanded and stained. The installer said that if the floors were sanded too quickly, then the reverse condition would occur. The wood needs to get back down to the 6-7% range. It currently is 8-9 %.They have added more insulation to the crawl, and are adding ductwork to the crawl ( this was the original agreement.....conditioned crawlspace) sealing the sump, and adding a dehumidifier. The main beam measured 17% moisture a few days ago. He claims it is a moisture issue that they are addressing. He fails to accept that regardless, it was their negligence. I am sick at heart and feel caught up in a no win situation.

Oh woe is me. I'll tell ya' this: I'd be ready to rip my hair, would lay down a moisture barrier and go get a really great engineered floor. I don't care what they do . A crawl space is that. : ) And a floor is just one aspect in a home. Above it are rugs and furniture and all the rest lol. I feel "bad mojo".......and more to come

Get construction attorney. Don't wave it in his face, but have someone advising you on how to navigate this. You will NEED to put it in writing - whatever happens.

If the wait and see fixes it - then that's cool -but if it doesn't.... you'll want the builder to pay for: furniture removal and storage, lodging for your family while you are displaced due to reinstallation and refinishing, any damage incurred as a result, painting / shoe mold as a result, etc.

You'll also want a timeline and a time is of the essence clause, etc.

If the builder wants to wait and see (kick the can down the road) then he needs to be prepared to pay for the additional expense that an unsatisfactory resolution causes by using this method. Usually, the delay tactic is one of simply wearing you down - and then if you are still unhappy, you'll realize how costly and disruptive it will be and you'll live with it.

I've worked in the building industry for 24 years and I've never seen a piece of wood go from flat to cupped to flat again. Never. I was on a job where the contractor put the floor down without letting the hardwood acclimate, it shrank and gaps showed up in between the planks. If you can, get an attorney and fight this.

I spoke with a NWFA inspector today and gave him the details. He said there is a 50/50 chance the floors could lay down. He said that by law we must give the contractor the opportunity to correct it and that we should make a document spelling out the details of what should take place to satisfy us with signatures and dates. It looks like at this point all can do is move in and ' wait and see'. He said we should know in 3 to 4 months. The builder is adding insulation at his cost, and a dehumidifier. There should have been ductwork installed in the crawl per our plan from the beginning, which will be installed. Water laid in the crawl for weeks coming from testing the plumbing and the sump pit before the sump was installed and running. I think that may have contributed to the moisture issue too. None of this was our fault and I feel that certainly things were not installed in the proper order. I blame our production manager for this. We simply can't wait 4 months to move in as we continue to pay rent and an interest only construction loan after 13 months already. I will let you all know what transpires in the way of resolution.

That was a good idea, to contact the NWFA. Please keep us posted.

You - "Jan, my last post was premature. My builder is now refusing to replace the floors and expects us to take the ' wait and see' approach. He says they will lie down in a few months, and if they don't he will have them re-sanded and stained."

I can't imagine being completely moved into a home, living there a few months and then sanding and re-staining the floors! Do you know how messy that's going to be?! (Of course you do.)

I did not mean move in. First Re SAND / , let acclimate even more, re do finish and when done move in.

However. Sometimes we stick square pegs into round holes. We have hearts set on something. I still believe the best solution is engineered over a moisture barrier. And ASAP

Jan, according to the installer the moisture content on the floors needs to return within 6-7% before any corrective measures should take place. They are now between 8-9%. He states that if they are sanded right now with this moisture level, then the reverse condition will happen when they dry out, creating just a different problem and not resolving one. We are in a no win situation here really. We plan to have an attorney generate a document stating our terms, that way there is no wiggle room for them. If the floors have to be resanded and stained but in doing so produce an inferior floor with gaps and such, then they should replace them. This is certainly not what we want to happen, but feel we should be legally protected because this is a significant amount of money. I hate feeling bitter and angry......that's not who I am. We can only live with the consequences of their negligence for the time being. We are so upset.

Your builder is betting that you won't tolerate the inconvenience of having the floors re-sanded after moving in. No way are you going to move out for a re-sand in 6 months. Not happening. He'll offer you a pittance then and you'll take it.

Sorry but hate crawl spaces for this application ...... Hate is mild :(

We built about 4 years ago and have hardwood in the majority of our home. The flooring company delivered our hardwood on one day and I tested with moisture meter and most was running about 9-11% humidity. The flooring installers arrived the next day and I refused to let them install flooring until it was at or under 8%....the had driven almost 50 miles one way to install but not my problem. I got them back about a week later and zero cupping.

We have a conditioned crawl space and the exterior concrete foundation walls have about 2 inches of closed cell foam insulation on them and the rim joist too...I went with a 3" concrete floor in the crawl and it has one hvac vent and stays dry and toasty and that is where our geothermal HVAC unit is.

Where is your contractor adding insulation? If you truly have a conditioned crawl space it is my understanding that the only area that needs insulation is the exterior wall and also there would be no vents in your foundation wall. One of the reasons we went with a conditioned crawl was because of all the hardwood in our home and we didn't want any moisture issues and cupping down the road.

bjjennings1954, the floors were installed before we had HVAC hooked up, no heat for 2 months, no duct in the crawl, no sump hook up or sealed sump, no crawl hatch door installed. The concrete walls are insulated with sheets of foam board, no vents in the exterior walls, no insulation between floor joists. He is proposing to add the ductwork ( as specified in our plan), add a dehumidifier to dry up the wood, and add insulation between the floor joists. The crawl hatch door was just installed yesterday. All of the things that should have been done BEFORE the floors were installed, apparently. He is attempting to get the moisture and humidity levels down and controlled. Too little too late for these floors I think. Guess we'll know in a few months. I see MAJOR inconvenience in our future. UGH.

Joseph, we will not accept a pittance. We will be FULLY compensated and have a legal document to back it up. I know what you mean though about him figuring we will not want to deal with it and just let it go.

bjpharr....sorry you had to go through this and hope all work is done to your satisfaction as it should be.

Wood will adsorb or desorb moisture depending on the environmental conditions (i.e., temperature and relative humidity.) Achieving an equilibrium is a process limited by diffusion--which means it's typically a slow one. As far as acclimating flooring goes, it may be fine to install flooring right off the delivery truck if the moisture content of the flooring is reasonably close to the moisture content of the subfloor over which it is to be installed. If not, it needs to approach the moisture content of the subfloor prior to installation.

In my personal home I've had problems with both a dishwasher and the ice maker line to the refrigerator which caused the hardwood flooring in the kitchen to cup. The cupping relaxed within a few months-- after the hardwood returned to equilibrium conditions. Bottom line: cupping of hardwood floors may be reversible depending on the conditions.

BJJennings1954 What has happened since your last post? We are in the same situation. I would appreciate any advise.

Curious as well. Similar situation. What was the outcome?

Also curious. We are in the same situation.

I can say that for ours they have not improved, or if they have, it's not been noticeable. Humidity is controlled at 50% or lower. An expert came to evaliate them about 8-10 months ago and confirmed that the subfloor contained more humidity than the finished floors. He said they'd need to be sanded, at which point we'd need to live with them unfinished until the moisture evaporates through the wood. They would then be tested to confirm that the humidity in the subfloor and hardwood are the same and then if so, refinished. We are not sure how to tackle this with high-risk family members living in the house combined with covid, not to mention the amount of dust, smell, etc., and living on unfinished floors while we wait for the evaporation to occur. But doing so during covid is the biggest obstacle.

I apologize in advance for tacking onto your post, but I needed to be with others who get this situation as I’m in a similar situation. When I moved in a year ago, my floors were fine.

But now they are not. The open area of my house looks like cupping, but it’s the groove edge that’s lifting. I, too, had an inspector from NWFA examine the floors. He said they weren’t acclimated at time of installation. There is no moisture problem. The builder said the floors can be sanded and stained. Inspector claims it may make the grooved edge bevel or split so they should all be replaced.

We have to let the builder try to fix them, but if it doesn’t work, he’ll replace them all which is fair, but oh what a mess.

I’m just so scared sanding and staining won’t work, and I dread then having to pull up all the boards, replace them and sand and stain again!

Here’s a photo of what they look like now. What would you do?

"When I moved in a year ago, my floors were fine.

But now they are not. The open area of my house looks like cupping, but it’s the groove edge that’s lifting".

That IS cupping. Rarely would that take nearly a year, all the seasons, to show up. Acclimated within the house or not.

If it is cupping, it looks pretty slight to me. Cupping--unless it's evident shortly after installation--is usually the result of moisture imbalances which are due to environmental conditions outside the contractor's control. Cupping is more evident the wider the flooring width which is why I recommend engineered hardwood for widths greater than 3"

As a point of calibration, the performance standard published in NAHB's Residential Construction Performance Guidelines for Professional Builders and Remodelers is:

"Cupping or crowning in hardwood floor boards will not exceed 1 /16 inch in height in a 3-inch maximum span measured perpendicular to the long axis of the board. Cupping or crowning appearing after installation may result from fluctuations in the moisture conditions in the house, causing a noticeable curvature in the face of the floor boards. Cupping or crowning caused by exposure to moisture beyond the contractor’s control is not the contractor’s responsibility."

If the OP wants to minimize cupping, they'll need to control the relative humidity in the living space as well as the space below the floor. If it's a basement or crawl space, moisture controls need to be in place and some amount of conditioning may be required.

No worries about tacking on....I understand your grief. I totally agree with the above paragraph. Our problem with cupping happened during the construction of our home due to negligence from our production manager. Because we are in a valley, surrounded by 100 year flood plain, very flat and about 250 feet from a creek, we had our home built on a conditioned crawlspace that has concrete floors, walls, and piers. We did not want to have moisture issues. Our cupping problem was pretty bad, so we wanted the floors replaced but the contractor refused. So after months of waiting for the floors to dry they were sanded and refinished.

It's been 5 years now and we have had no more issues with the flooring. So I agree that if there is no moisture control in the basement or crawlspace, there will always be some cupping and crowning with the flooring with humidity fluctuation.