We are installing on a porch that we converted to 4 season. My husband wants to put insulation board underneath. What is the recommended thickness?

Hello Hwhit - thank you for your inquiry. Installing the Style Selections English Grove Oak is suitable in a 4-seasons room. However, please keep a few things in mind. The site conditions during installation must be kept between 60° - 80°. The optimal temperature for the room to be maintained is between 40° - 90°. Expansion gaps must be increased to 1/2" around the perimeter. You must also use window treatments on any windows. And a transition molding piece must be used between the 4-season room and the connecting room. We don't have a recommendation on the thickness of the insulation board - other than to use something with the highest r-rating as possible. Again, the temperature in the 4-seasons room is critical once the flooring is installed. Hope this helps with the 4-seasons room preparation. Good luck with the project. Thank You -