I bought 1500 sq. ft of Kempas 4 and 3/4 inch solid wood plank 3/4 inch thick.

1. GLUE O0R NO GLUE?? - Instructions state use #15 felt paper and nail or staple. BUT I have had several installers state that I needed to use both staples and glue (and not use the felt). Installers were afraid of cupping. So the instructions are saying no glue, but two potential installers are saying all glue or bead one side with liquid nails and staple the other side with no liquid nails. HELP!! I called the distributor - no help - no call back yet.

2. HOW MUCH ROOM FOR EXPANSION AND CONTRACTION - Instructions are silent on expansion and contraction.

Gluing a floor down does not prevent cupping. If it did, then floors glued to concrete would never cup. Some installers get nervous about nailing down a plank floor without gluing it as well. I would feel confident about nailing only a four inch wide floor down, as long as existing subfloor was FLAT and STOUT, and there was no evidence of moisture. You can do both; nail only with the asphalt paper OR nail and glue with NO paper. A 1/2" expansion space is adequate in most circumstances.