Our new floating floor for the kitchen needs to be on a solid and level sub-floor. After walking around & feeling sections give & squeak under his feet, our contractor recommended that we go all the way down to the floor joists & reinforce them. Opening up the floor also make it much easier for the plumber to extend the gas line to the far wall for the new location of the range and a little easier for the electricians to crawl under for that complete house rewire. So all in all, we took up 3 layers of vinyl & original linoleum, one layer of 3" wide pine tongue & groove sub-floor and the final layer of 8" diagonal cross beams. The kitchen looks so much smaller now that everything is gone.
(you can follow the link from this photo to Baubcat's 'Kitchen Renovation' Set on Flickr)