These floors are 1 x 10 reclaimed doug fir in 16' lengths, installed with copper nails, and we used an oil-based satin polyurethane on it. For best results, the wood should be kiln dried.

Kiln dried wood will have a moisture content of between 6-8% on average when removed from the kiln. This makes it "furniture grade" and ready to made into flooring. The lumber will gain several points while being made into flooring and eventually installed. Kiln dried lumber will be more stable than air dried lumber. :-) One more thing - Reclaimed lumber should also be heat treated to kill any bugs that may be hiding within the materials.