This is the traditional method and the only way a solid floor should be installed. When you have a solid floor installed in your house this usually means you have a 3/4 inch thick and a 1”- 5” width. When installing a solid floor the floor must by acclimated to the humidity and moisture content of your home, this should be done before every installation. A solid floor will expand with every season so be sure there is a ¼ inch expansion minimum everywhere in the floor or this will cause problems later on as your floor needs to breath with the seasonal changes. If you are installing over a crawl space, you should open a vent in the crawl to help keep a more consistent temperature and to rid of the moisture so your hardwood floor won’t suck it up, this will cause gaping and cupping in your flooring. This should be installed with a 2” staple or cleat with a layer in between the plywood and Hardwood flooring to stop the wood on wood contact. By following easy steps you will have a flawless installation on your solid floor, be sure to hire a professional installer to get the job done right, we can offer this to you so you can have a clear conscience that your floor is perfect.