Could improper nail down of the sub-flooring be a problem?

Q: I had a pine wood floor with 5 inch planks installed in my home on May 22nd. The first problem I encountered was that the installer brought the wood into my home and installed it the same day.

I keep the temperature of my home around 68-70 degrees. Within 2-3 days I had gaps wide enough to fix 3 to 4 quarters in them.

The installer agreed to come in and take up the flooring and replace it. They removed the flooring (except for the Master Bedroom Closets) and left the sub-flooring they installed. They dropped off the new wood this time and I made them leave the wood in the home spread out among 4 rooms for 16 days. After that they installed the new floor and came back 6 days later and sanded, stained, and put two coats of water base finisher on the floor.

Now is where the problem occurred. Within two days after the water base finisher was applied, the floors cupped in the two Master Bedroom Closets and the small hallway between them. When tested, the floor moisture was 65%. The rest of the room was around 6%. What could have caused this other than a plumbing leak? The closets back up to the bathroom and are opposite sinks…. (more details included in email)… When I bounce up and down on the flooring by the threshold that was removed, you can see the sub-flooring move up and down about an 1/8″. Could improper nail down of the sub-flooring be a problem?

A: Improper nailing won’t cause cupping of the boards. The only thing that will do so is excessive moisture causing the wood to swell and press against the boards beside it. It does not surprise me that the closet is near the washroom, and I think that must be where the cause will be found.

It was certainly a mistake to bring the wood in initially and install it the same day without allowing for acclimation. Did they also test the moisture of the sub floor to make sure it is dry before installing?

It sounds to me you have a leak or you have moisture coming through ceramic tiles in the bathroom…. something of that nature.