I am replacing a couple sections of subflooring for a bathroom project. The original subfloor is OK -- it's the 1/2" subflooring sitting on top of the original that I am replacing. My questions: 1. What type of fasteners would be the best? screws, nails, staples? 2. Do I need to add adhesive between the 1/2" subfloor and the original subfloor? e.g. Liquidnails 3. What is the recommended spacing for the fasteners? Thanks.