We live in an early 20's craftsman built with varying degrees of quality. One of the things the builders skimped on was a decent subfloor. We want to replace the existing hardwood in the dining room which has been repaired/refinnished too many times to be salvaged. The subfloor consists of only 1x6 planks running perpendicular to the joists with about 1/2 inch spacing between them. The hardwood is laid directly on top of this. I have looked from the underside and the joists all look good but there is some slight surface molding on the joists and underside of the planks. The floor also currently squeaks quite horribly just about everywhere. My current thought is to rip everything up down to the floor joists, have a termite guy inspect and spray the joists to kill the mold, screw+glue down a new plywood subfloor, and then laydown a floating engineered plank floor. Seem reasonable?

A friend recommended 5/8-inch tounge and groove plywood (PDX I think he called it) for the subfloor. I may actually need to use 1-inch or two layers to get it close to the old floor height. Sound reasonable?

Is there any structural risks in ripping up the entire subfloor in a given room, like the floor joists possibly shifting? or anything severe like that?

The walls are all lathe and plaster and I would rather not have to rip all the walls out and refinnish them too so I would like to keep the existing 1x10 baseboards in place. The baseboards are fairly well stuck into place with the plaster and removing them causes the plaster to start to crumble up the wall. Sound feasible? I realize I might have to add some cross joists for support at the edge walls if there is no exposed joist at the walls parallel to the joists.

How do I cut out the old subfloor flush to the wall/baseboard? My best thought so far is my sawsall/reciprocating saw with something held flush to the baseboard to prevent damage.

JAson