Hi,

I have a room, roughly 16'x16' that we just installed with new prefinished 2-1/4"-wide red oak hardwood floor.

The new floor is unfortunately uneven. When we walk across planks, our feet can feel the highs and lows. What can we do to fix?

Hopefully you can see pictures here: https://photos.app.goo.gl/zH8vGK83xBE33wTX7

It is not the flooring. It looks like the floor was laid over an uneven sub-floor.
The problem may have been remedied with thick tarpaper in the low areas, after the high spots were sanded down with coarse sandpaper on an edger setting nails as necessary so as not to dull the paper.

Thanks, Pete.

Are you saying that this is something that could be remediated while laying out the floor?

Since the floor have been nailed down, what can I do to make it better? Is it possible to remove a few planks and re-do it? Fix it from crawl space?

Thanks again.

The time to fix the problem is before the flooring is laid. I don't know how you could fix the floor from underneath. It would be difficult to know how much filler to add under each row to get close to flat.

Unfortunately, the installer should have checked for flatness before starting. Take a 8 or 10ft straightedge to the space and check in all directions for flatness, the goal being to sand high spots or patch low spots and come out as close to 1/8th over 10ft as you can.

Once the floor is installed, the only way to fix it is to do it again. Depending on who signed off on the subfloor, you may be able to make a deal with your installer for the re-work.