Hardwood floors should be installed according to National Wood Flooring Association (NWFA) guidelines https://www.georgiaoakfloor.com/images/pdf/NWFA-Installation-Guidelines.pdf The HVAC system should be operational or a temporary system should be operated to mimic the same conditions produced by an installed system. The flooring should be acclimated prior to installation as per the guidelines.

The only option is to get hvac running, get the interior stabilized for a while, and re evaluate. They may flatten, they may not. Blaming the old contractor at this point is a bit of a reach by the current contractor since it’s been nearly a year and he’s been in charge since dry in. Ugh you must be exhausted.

As mentioned above, get the HVAC up and running, wait and see. If, it does not flatten out, then you have permanent damage that needs to be addressed by refinishing the floors. This should be warranteed by the GC.

Thank you all. It’s very hard to argue/discuss your side when you have no background in building.
May I ask one more question? The wood floor was sanded once already then sealed with Bona. If we have to sand it again that is going to take quite a bit off and most likely in an uneven fashion to plane out the bumps. When you are trying to sand out cups how will you know if the floor just needs to be replaced? Thank you all. Reading your responses really helps our anxiety levels.

You want your hardwood floors to be stable before doing anything. That could take a number of weeks after the HVAC is operational. You can revisit the cupping at that point. You didn't note whether the foundation is a basement or crawl space, but controlling the relative humidity of the environment below hardwood floors is important, too.

You can sand solid wood floors up to 5 to 7 times depending on flatness.

if, your main concern is the building aspect. tear it all out and start new. you will need to dry out the subfloor first before proceeding.

I am not a builder, just wood floor specialist.

I didn't really have to read the post, but did. The title says it all. Chas hits the spot.

"You didn't note whether the foundation is a basement or crawl space, but controlling the relative humidity of the environment below hardwood floors is important, too."

It's critical really.

"he says he has never had problems..." Yea right

Time may fix this. Time may not. But, getting that house's HVAC operational is the second step. The first step is controlling any other moisture that might enter the home.

All of homes we design and build are on conditioned crawl spaces or basements. That said, I have noticed that wider flooring widths are more susceptible to cupping or crowning and keeping indoor relative humidity around 45-50% is critical (I have some clients who want to keep the indoor temperature close to 80F in the most humid summer months and that's a recipe for problems.) The OP notes 4" wide floors. I recommend to my clients they choose engineered flooring for widths over 3"

It is a crawl space. Partially sealed on the walls but needs the final plastic sheeting. It has been open all this time(2 crawlspace doors and all the vents open to the inside- we could see the ground from the vents in the inside) The HVAC guys just started connecting the vents underneath in the last 2 weeks.

Sounds like timing was more critical than doing the job right.

Since, it is on a crawl space was any moisture proofing done to the top of subfloor? what type of subfloor do you have - planks or panels?

"It has been open all this time(2 crawlspace doors and all the vents open to the inside- we could see the ground from the vents in the inside)"

G & S Floor Service

Wow, can see the ground from the inside. Floor needs to be removed and subfloor redone. This is a building issue not flooring.

After you address the crawl space issue. The subfloor needs to be sealed from the top, including all expansion gaps between the panels and perimeters.

"refinish the board humps when the humidity level drops in a month, or 2 weeks minimum."

It's unlikely that cupping would be resolved in 2 weeks or a month and generally the cupping will lessen or disappear when the moisture level in the wood reaches equilibrium. When the floor has finish on it, acclimation can take a very long time. I would recommend waiting a year to see how the seasonal changes affect the profile and have the builder commit to backing it.

That said, I'd highly recommend a professional inspection to gauge levels of moisture in the tops and bottoms of each board and in the subfloor, to determine the source of the moisture and eliminate potential causes that might not be obvious.

There's fairly high probability that if this isn't done right, it will never be right, like forgetting to put sugar in your cookie batter, then pouring a bunch on top of the finished cookies as a remedy.

"We asked the advice of a local contractor who said the floors should have been installed AFTER the HVAC and then finished."

Correct.

"Our GC said he did not budget for this and was not planning to refinish our floors."

You get budget surprises when you're stupid.

"we could see the ground from the vents in the inside"

"Wow, can see the ground from the inside."

I'm pretty sure this is the HVAC vents that come through the floor where one could see the ground before the ducts were installed.

Thank you to each and every one for the input. It has helped tremendously.

May I ask one more question? How much cupping is normal?

The GC says wood floors are a natural product and are going to cup and he's not worried about the amount present on our new floors. If I run my hands over the floors I feel small speed bumps over where the boards join. We did not have this in old house at all. Thank you all in advance.

Visible cupping is not acceptable. Post a picture.

A bit curious where in NC you are building and who your GC is (and was).

I would be consulting a lawyer if I were you unless you have a large hold back.

Just a comparable tale. I was having floors installed in Nov/Dec. Engineered which are more stable. On a slab protected by foam and vapor barrier (although I forget the exact details). My installer had a humidistat on the subfloors and the house was closed up. We had a small leak in the powder room and I had to wait until about a month after closing (maybe not that long...) because the installer wouldn't touch it until his humidistat (specific for subfloor testing) reported 14% or some low teen number.

That hardwoods don't like humdity variations is something everyone should know. The plan of installing hardwoods in April on an open house and finishing in August is not "standard of care".

Anyone who owns hardwood floors and has a house in NC should become well aware of this. There is a reason that you don't see hardwoods at the beach very often because of this. I did my steps in hardwood there - and I need to go replace 30% of them this winter despite a closed house. I can't keep the humidity consistently down there with renters.

I suspect your hardwoods need to be replaced. I don't think your subfloor is a problem as these are pretty stable and designed to handle humidity variations.

As an aside, might want to seal the crawlspace during the build process. A vented crawl in 2022 in NC - really bad idea. Your ducts and subfloor will be seeing the humidity swings forever with a vented crawl. Ever see insulation after a few years in a vented crawl?

Sorry but cupping is NOT NORMAL

Wood is a natural material and it will adsorb and desorb moisture depending on its environment. Cupping or crowning may occur. The National Association of Home Builders Residential Construction Performance Guidelines for Professional Builders and Remodelers gives an allowable tolerance for cupping--which is not to exceed 1/16" height in a 3" maximum span measured perpendicular to the long axis of the board.

Unfortunately, the NWFA standards for cupping are hidden behind a paywall. Way to further your industry.

TCNA handbook is behind a paywall too...

I am going take a picture in the am. i really appreciate everyone's input

Wood should have been in the home for several days/weeks with the HVAC running and low relative humidity prior to install. We've ALWAYS done it that way with both unfinished and prefinished. Because our new home is on a river and lots of foggy mornings and humidity, we chose to have our 7" prefinished white oak nailed and glued down to ensure no cupping or warping. Two years in and they are still perfect :)

That said, I had a refrigerator leak on our new floors in a previous house, which caused noticeable cupping. I was sick but, at the advice of our friend who is a flooring professional, we put a fan on it for a few days and waited. It took a month or so, but the wood finally went back into place.

The house is being built in Hillsborough NC. The sealed crawl space is underway. We added a dehumidifier to the HVAC and a humidifier will be added also to hopefully maintain a consistent level.
We are supposed to be done by October 15. I will post the names of both builders.

You don't necessarily need humidifiers and dehumidifiers to maintain consistent humidity levels in Hillsborough. What you need is a tight house and the sealed crawlspace helps for sure. I had a humidifier in my last house and my current house does not. There has been zero difference in humidity fluctuations. Beach and mountains - different story.

Right now is a particularly high humidity in my house at 55% - mostly because no HVAC at all. But not sure I would want a dehumidifier running now since the humidity will fall once the sun comes out I suspect.

The absolute only time humidity gets above 55% is when we cook a bunch and run the venthood for a while. Just making the point that infiltration drives humidity.

Similarly in the winter, running the venthood will drive it down. But I haven't seen below 40% and that is a pretty typical setting for a humidifier. So if we had one, it would never run.

I would personally wait on the humidifier and see what happens. Presumably in Hillsborough, your house is built fairly tight but no guarantees.

Work in Raleigh? or at least used to?

Yes. I think our paths may have crossed :)
We requested the dehumidifier before any of this floor business for the purpose of respiratory health. We discovered later it may assist the AC use in the summer.
I just found out that the HVAC is still not on a week before getting CO. He’s not even trying to get this right. He told us he has 17 other projects going. That might give you bragging rights for a social setting but not a customer who is already feeling neglected. I’m nervous about putting this floor on a punch list. Lucky us.

Mr Hallett, I hear you. I bought the $50 TCNA handbook. Our steam shower was installed by one of our GCs tile guys who had never done a steam shower. He used the “splotch technique” for the mortar and we had to demolish the whole thing and start over with another tile guy. I wanted a documented standard because the GC supported the tile subcontractor’s technique. I have another post in Houzz about the steam shower. This forum is so helpful and I appreciate everyone’s input.

I've been running a dehumidifier in the new house until the HVAC is done. Throughtout the summer - keeping humidity under 40% has made it comfortable to work in the house despite it being in the low to mid 80's.

We'll have dehumidifier for the whole house - but not a humidifer. While it does get dry in the winter - usually does not last that long.

(Wake Forest)

And anyone building in NC ought to know the biggest challenge is with moisture management. Rookie move by the builder.

Is Cindy Everett the same as Cindy Everett??

Hardwood floors will cup when exposed to dampness, humidity, water.

If your environment leads to moisture, as it does here on Cape Cod with ocean surrounding and high humidty in the summer, engineered hardwood is the only way to go. Your floors will dry out and it won't be as noticeable, but you always will see the tell tale signs.

From what information you have provided, your contractor should be held responsible.

The two Cindy Everett’s are the same. I had a problem with Google and switched to Firefox. Houzz didn’t recognize me so in trying to switch my password created the new account. I would like to merge the two. Just haven’t found the time.

I would like to post an update. I contacted a local member of the NWFA to assess our floors. By the time he came the floors were also separating to the point of being able to roll a quarter down the trench. The HVAC was in full swing. The results of the report revealed that the floor boards were at correct humidity inside and under the crawlspace. He gave us a 13 page report that also revealed missing areas of nails or staples used to secure the floor to the subfloor. He has a magnet to determine spacing of fasteners. His conclusion was that the floors cannot be repaired and should be replaced, unless we want to have someone insert putty between all the spaces, which would probably look worse than the spaces.

I'm sorry you had to go through all this. I might suggest that if you're planning on redoing the floors you instead look into using Engineered wood flooring for your area. My floors here in SW FL are engineered 5" wide white oak and in the 4 years we've been in the house, we've had no issues with it. And in our old condo, we had 5" wide Ipe floors for well over 8 years with no issues.