I found this on the Shaw flooring site.
Quote:
Do not install over nailed floors that exceed 3-1/4" in width. Wide width floors must be overlaid with plywood.
When installing over existing wood floors parallel with the flooring, install an additional 1/4" layer of plywood to stabilize the flooring, or install the new wood floor perpendicularly.
I haven't decided on a final pattern yet but i will be adding a border around the perimeter of the room(s). The border will be running parallel to the existing 2x6s, so i'm hoping the 1/4" plywood will do.
I probably will have more questions as i get into this. I'm pretty handy, but have only installed laminates in the past.
thanks for both of your answers.