Could be two matters.

1- Bad material. How much was paid for it? Some stuff has it's limitations. IE: crooked boards that won't straighten out. Even shorts.

2- Bad starting point, not aligned or kept tight and square.

If the installer legitimately thinks there is a milling problem they need to stop installation right away and contact your dealer for replacement material or at least a consultation on the quality.

And WHY is this 'nail only'? These are 5" HICKORY planks. A wide plank floor (anything 5" or wider) must have glue assist during install. And hickory has a little bit more movement than oak...which means it needs a bit more stability (ie. glue assist) when installed.

The "American Spirit" brand is sold by Floor & Decor. Their installation instructions are...limited. Which means the installer has to have quite a bit of knowledge to know all these things. A guy with a hammer (or nail gun) will have little flooring knowledge.

At the price of $5.29/sf (as listed for a store in WA state) the chances of milling issues could be quite high. I think we have several issues going on here. As Oak & Broad suggests, start by CULLING all the boards that are BAD (this is what you are paying your installer to do...but he's not doing it so it falls to you to go for it) and then find out your TOTAL square footage of bad boards. Figure out if they are MORE than 5% (industry standard allows 5% waste for bad wood). If your culled footage is MORE than 5% you have a claim worthy of the paper it is written on.

And while you are culling your wood, have someone that is well versed in wide plank install come in and have a look at this install. I'm PRETTY sure you need glue assist on this one. A 5" solid hickory plank (3/4" thick) for LESS than $6/sf is going to need some help.

And please tell me that it was acclimated for several days/weeks. And please tell me your installer took moisture readings from random planks equal to 10% of the wood delivered to your home. And please tell me the boxes were opened and stacked PROPERLY while acclimating.

And good luck with Floor & Decor. It's my understanding they take quite a bit of time to get moving if there is a claim that they have to deal with. The sooner the better is what I've heard.

"And please tell me that it was acclimated for several days/weeks. And please tell me your installer took moisture readings from random planks equal to 10% of the wood delivered to your home. And please tell me the boxes were opened and stacked PROPERLY while acclimating."

Last pic from the OP pretty much should sum up all those questions SJ...........................

Thank you all for your input. The planks were in the garage for a month, but had not been acclimated in the AC room for a single day! I stopped the contractor after his first day’s work because I found out he started installation right after he pulled the planks into the house.

I am going to hire a inspector. Thanks again!

"I am going to hire a inspector."

The inspector will tell you the installer doesn't know what he is doing. There is much more as SJ alluded to then even just acclimation and none of those steps sound as if they were followed. Personally I would cut bait with this installer and find another.

Hi Milleorkman, yes, I bought the floor separatemy.

Thanks!

Thanks SJ McCarthy. I did not pay for the installation at all! I did pay them to fix the subfloor (insert another layer of .5” plywood). The work was good on that. But I realized today,they overcharged me for that. For 1000 sqt, they charge me $7,000 ( labor + material). I paid them $4,000 up until now.

Uh oh....and how long was the plywood in place BEFORE they installed the wood floor? If they were BOTH damp, you are going to have even more issues.

If we assume the 1/2" plywood is $1.50/sf and the install is $1.50/sf, then a total of $3/sf for the subfloor would be roughly where we should be. It is possible, with some issues happening, that $4/sf (labour + materials) for subfloor prep can occur. Asking for $7/sf for subfloor preparation is PRETTY high. It is very, very, very rare to see numbers this high. Something weird has to be going on for this number to be SOOOO high.

Is this plywood over concrete? Is this over wood joists? Were there issues with hills or valleys in the floor that required +++++extra work/materials to be used? How old is the house? What was the problem with the existing subfloor that required 1/2" plywood?

SJ McCathy, you are so helpful. they did not climate the plywood either. They did not check the moisture.

The original subfloor is not good. I believe it is called OSB board. It is old (40 years) spongy and not even. they told me they can‘t install hardwood floor on that. They did not remove the original sunfloor, but added another layer of pine wood plywood. I sort of knew the issue before I bought the house. Just did not realize this is going to affect hardwood floor. They told me after they pealed the carpet off. I did not look for 3rd party advice on this unexpected issue.

My my first project on hardwood floor. I am learning a lot and learning in a hardway.

Hmmmmm....laying new plywood over old spongy OSB is not normally something we recommend. Spongy can often mean 'wet' or damaged. The reason for the sponginess should have been investigated (you should have been informed, you should have been told the BEST way to deal with it is to find the REASON why there is a spongy surface and then to make the best possible decision based on the issues discovered by the investigation).

Did you hire a General Contractor (because there was other work to be done) or did you hire a Certified wood flooring installer with 10+ years in the business?

At this point, I would pull the plug on these guys (at least for the flooring segment). You have probably paid full market value for the services they have already performed (flooring stuff). I don't think you owe them anything.

I would get in a certified professional to come in a fix what needs fixing and to investigate why the old OSB was spongy (if it can be done). Old OSB can remain fully functional over time...that's not the issue. The issue is why it would turn spongy. Laying new over 'bad' is not the way to go about this...or it isn't the best way.

Sadly, I think you are out the $4K you have already spent on this floor. I'm going to guess most of the work is usable, I'm just afraid they covered up a massive problem that you will now be faced with a remove/fix and replace project not yet budgeted for.

Please bring in an NWFA certified pro and get them on the case. Ask some questions about how to go about cutting ties with the 'guys' you have already paid $4K. The pro might have some insight into how to go about this with the least amount of push back.