Contact your builder.

Cupping may be caused by humidity. Purchase several hygrometers and a moisture meter, measure the room humidity and floor moisture.

Sometimes, the flooring requires specific environmental conditions.

Control the moisture from below or tear out the flooring and upgrade the moisture retarder under the floor and install engineered planks.

Planks and wide planks need an upgraded moisture retarder such as Aquabar, roll-on products or the use of a silane base full spread glue to allow movement. Aquabar is the cheapest upgrade compared to the other two.

Cupping (when the long edges of the planks are HIGHER than the centres) indicates the moisture is too high BELOW the planks. Crowning (when the centre is higher than the edges) is when the moisture is too high ABOVE the planks (as in the air humidity is very high).

Which one do you have? Do you have photos? How old is the house? What type of foundation is the wood sitting on (wood over a basement/crawlspace or cement slab)?

Whomsoever installed the flooring is responsible for it. Call them to bring them in for immediate inspection. While you wait for them to get back to you, feel free to up load some photos for us.

Definitely cupping . You can see the heat vent lifting off the floor over a seam in the wood planks. I’ve been in the house 10 months.

Yes...but how old is the house? Please take photos of the floor from a distance. The photo shows nothing but a floor vent sitting 'up'. We can't see the wood itself.

If you take a photo of the floor with 'back lighting' (as in the sunlight pouring in and it HIGHLIGHTS the ripples in the floor) then we will have a better understanding of what is going on.

And we still need to know what type of SUBSTRATE you have (concrete or wood)? Do you have a basement?

The house is brand new. 1700 sq ft ranch. There is a full unfinished basement and the subfloor looks like particle board.

Another view

Too much moisture is moving up through the basement. What have you set your whole-home dehumidifier at? Do you have one?

You are going to test the moisture levels in the basement (RH = Relative Humidity = moisture in the air) as well in the rest of the home. Someone with a wood moisture metre will have to test the wood flooring AND the wood subfloor.

How long ago did the floors start to cup? When did you contact your builder? And what was their response?

If, you can't find any leaks in the basement. You will need to run 3-4 dehumidifier units to control the humidity in the basement. Buy units with automatic settings, this way it is not always running.

I have neither a humidifier or a dehumidifier. The builder sent the floor contractor out to see it. The floor guy told me to run a dehumidifier in the house. But Izvestia got my heat on now so I don’t see how that will help. All of this started in the summer. But there was an area in the sitting room that was cupped when I moved in and I let the builder know immediately. Nothing has been addressed directly by the builder yet.

There are no leaks in the basement.

Is is the responsibility of the builder to do all this testing of the wood and subfloor. I wouldn’t have a clue where to begin.

Will running the dehumidifiers in the basement “fix” the cupping or just prevent it from getting worse.

It should fix it, unless there are permanent damage like crushed edges. And yes, this is the GC's responsibility to handle it with their flooring contractor.

Thanks for all your help. You’ve all been amazing!

@Cheryl can you keep us all in the loop as the dehumidifiers do their work?

Hygrometers and moisture meters are available for ~$25 each. They are also available for rent.

Summer is the 'wet' time of the year (high air borne moisture = high RH) whereas winter is the 'dry time' because the heat is on. Heat dries out the air (that's why our driers run HOT = remove moisture from clothes). The drier winter air *should reduce the appearance of cupping.

It *should fix the problem...for the WINTER months. What it will not do = fix it forever. A basement dehumidifier will need to be run during the summer months and probably the A/C unit will have to be run from spring until fall to keep the humidity levels down during the summer.

These are considered temporary fixes. A permanent fix would be a whole home dehumidifier/humidifier. The HVAC company that produced the heating/cooling system in your home would be the one's to contact should you wish to upgrade your system.

But at this point in time, it is the Building Contractor who needs to be dealt with right now. Do NOT let them off the hook. Keep pushing. If you must, go ahead and have the floors inspected by an NWFA Certified Wood Flooring Inspector (www.nwfa.org). Someone like a certified flooring inspector will show the Builder you mean business and that they will NOT get away with a poorly conditioned/built house.

Thanks for your input SJ McCarthy. I’ve ordered a large dehumidifier for the basement with a pump. I will look into having a whole house dehumidifier installed .
I will get the GC to get over to the house today. Exactly what should I demand of my GC? Do you think I should ask to get the floor replaced. Or would getting them to install the proper HVAc dehumidifier be sufficient.
Hygrometer reading down the basement is 76% and 64% in the living area. Is this normal? And what should it be?

Hi Cheryl...sorry to take so long to answer. I didn't get an update for your post (oops).

A wood floor (anything wood actually...and any finish in the home including paint, drywall, cupboards, doors, trim, windows, etc) rely on indoor living conditions.

Believe it or not, there is an 'industry standard' for the definition for "indoor living conditions":

Temperature to be maintained between:

* 15 Celsius - 28 Celsius (59 F - 82 F)

Humidity to be maintained between:

* 35% - 65% Relative Humidity (air borne humidity)

When it comes to wood flooring, the floor (your pretty stuff that is cupping) needs to be within 3% of the moisture readings for the subfloor.

An example: Subfloor moisture reading: 11%

Wood Flooring moisture reading: 9%

This is an acceptable range for INSTALLATION. That is to say, the install is allowed to go ahead with readings such as these.

To be blunt, your indoor humidity readings are FAR TOO HIGH. The 12% difference between upstairs and downstairs is what is causing the cupping. The moisture in the air is trying to move down it's own concentration gradient (moving from wet areas to dry areas). It is doing this by moving THROUGH your floors.

This is why you need to get the builder in here ASAP!!

Their readings BEFORE the floors were installed (and with readings of subfloor AND wood flooring) and how LONG the wood was acclimated ON SITE and the SITE CONDITIONS at the time of install (was the HVAC up and running or was the builder saving money by keeping the heat off = not having to pay the electricity/gas bill while the house is being finished) are PARAMOUNT to their defense (against future liability).

If they do NOT have them = you win. But this could get ugly. So be prepared. I would question the HVAC mapping for your house. I would question the viability of installing hardwood with an HVAC system not properly 'tuned' (our sourced) specifically for humidity regulation.

I'm not an expert about what you can ask for. It depends on what the HOMEOWNER was allowed to choose versus what the BUILDER provided (what costs included basic systems vs. what upgrades should have been ordered to maintain homeowner choices).

For instance, the HVAC might have been a base model with no particular function other than heat and air movement. The LOCATION of the house and the SIZE of the house might not have been taken into account. The size of the basement and the amount of air exchanges might not have been calculated correctly. The issues could go on and on.

Or they could have been perfectly suited for the house but the homeowner might not have turned things 'on' due to personal/financial choice.

Whew. You can see how TWISTED this gets just by asking 'what can I ask for'.

See what is on offer. Get all the inspections you feel are necessary (wood flooring inspection with HVAC inspection/mapping/calculations) and then see where the 'foreseeable problems' SHOULD have been mitigated by a professional Construction Company licensed in your State.

SJ McCarthy,
Thank you so much for the very thoughtful and excellent response. I did contact the builder and they have been very responsive. They admitted there is definitely a problem with the floor. ( Unlike the floor guy who pretty much dismissed the problem). After I took the hygrometer readings they basically told me what you did about the humidity and floor. They are going to replace the area of floor that became wet ( due to a leaking door) immediately. They are also going to check for the water barrier between wood floor and subfloor when this replacement occurs. I bought a dehumidifier and the builder brought another one over, so now the basement is drying up nicely. They reassured me that they would definitely replace the floor if the cupping does not resolve, even after the “warranty “ period is over. I feel confident they will honor this as they are just starting this small street and don’t want a bad name.
The important thing is, with all the information you have given me, I was able to sound knowledgeable and well informed about the floor problem when talking to the builders. They definitely seemed to appreciate a well informed customer.
So thank you again. Your information was extremely valuable.
Cheryl