Uneven subfloor causing floor to lift

Q: I recently installed a Bruce floating engineered wood floor. In one particular area I had an uneven subfloor that I attempted to fix with wood putty. I also added an extra layer of the roofing felt to help build up the area. Once I felt that it was even enough, I continued installation. After installing over that particular area, I have noticed that I still have some unevenness causing the floor to lift up on the high side.

I haven’t put down my quarter round yet. I hope that once I have the quarter round installed it will help hold the floor down. What would you do in this situation? Should I screw down the boards that are lifting up? Should the quarter round help prevent it from lifting? The area is in a foyer where there is lots of traffic.

A: Sounds to me you “filled” the low spot too much. One of the requirements of this sort of floor is that the sub state needs to be about perfectly flat. I would take the floor up to that point and fix the problem.