Q: I just had a flooring contractor sand and stain a new oak floor. The floor surface is wavy, as if the sander was not operated correctly and dug in too deep in places.
Is there a way to achieve a flat finish? Will this require re-staining the floor?
A: It is likely that his sanding machine is out of adjustment. That would be up to a machine mechanic to diagnose. I had such wave appear recently on one of my jobs. Not very severe. The technician found a flat spot on my drum. As for cutting grooves, either his drum is out of adjustment or the floor and sub structure is not flat. This often happens along walls, and can make sanding this area very tricky.
It can also be very difficult to see initially and only really becomes visible after a couple of coats of finish are applied. The only way to get rid of all this is to do the job over. The floor would have to be cut on an angle first to remove the wave.
I don’t know the character of the flooring contractor who did the work. To be fair though, I have to say that these sorts of problems can happen to even the most conscientious worker who maintains his equipment. If he cares about what he is doing, probably nobody feels worse than he does when a job doesn’t turn out as well as his hard work deserved.