I'm going to install a basement subfloor. I want to follow option 3 from this site: http://homerenovations.about.com/od/additions/a/BasementSubfloor.htm.
A nice option because the foam insulation provides an excellent thermal break between concrete and flooring. Finish flooring. Plywood screwed down through the layer below. Rigid foam insulation - 1 1/2" thick. Concrete basement floor.
For the rigid foam insulation I wanted to use XPS foam. My question is, do I need sleepers for this? I saw on YouTube someone using a similar solution but they used sleepers under the plywood and filled the space between the sleepers with foam.