Can I put those peel and stick linoleum tiles over wood sub-floor?

Question

It's not hardwood flooring it's just the plywood on the upstairs floor under the carpet.

Answer 1

Depends on the quality of the plywood surface. Any imperfections in the surface will eventually show though. Best thing is to lay down 1/4 lauan ply over the subfloor. Either glue it or countersink screws and fill. Also fill any imperfect seams.

Answer 2

The lines in the floor will show through. Use a "Level set" to off shoot this pattern. It will give you a better job.