[JavaBrewer]

Depends on the wood product. Engineered wood floors are a glue down install. Solid hardwood floors are a nail down. Engineered has come a long way are are IMO the best product out there. They are pre-finished and many can be refinished down the road 2-3 times. Most newer (10 yrs or less) slabs in Cali are not prone to moisture problems (vapor barrier is put down before the pour) but still a test should be done. Prep is important - slab must be clean. After I demo'd the existing carpet and vinyl flooring I hired out guys using machines and strong chemicals to strip and buff the floor totally clean. Don't skimp on glue - Bostiks Best runs somewhere around $175/5 gal and is the product to use. Yes nasty to work with and figure on tossing all clothing worn by the installer. My floors have been in for years and are as solid as ever.