After I finished nailing the third row, which is actually the first hidden nailed row, I stepped on it. It was good. But after I finished the 4th row and stepped it again, 2 short solid wood planks of 3rd row squeaked. The sound was obviously from tongue and groove. I'm wondering how does that happen and how to prevent squeak in installation. To fix squeak, can I add couple face nails to those two short planks?