I plan to float a bamboo floor over top of our kitchen's existing linoleum (or vinyl, not really sure which). The problem is that the floor has a couple of high joists that make it pretty uneven along the width of the room. The height difference reaches half an inch in the worst spot. How can I smooth out the floor?
Floor details: The kitchen sits above a partially unfinished basement (meaning we have access to some of the problem joists). The subfloor* is 3/4" OSB. On top of that is the "linoleum", which is backed by wood so that it's about 1/4" in total thickness.
** Room details:** The room is a U-shape about 18' wide that opens to the rest of the house after a length of 20'. The cabinets line the "curve" of the U, with the bad joists cutting "across" the U, just past where the cabinets end. At one end of the bad joists, there is a sliding door that we intend to replace.
We installed the cabinets on top of a 1/2" spacer (to fit the bamboo) directly on top of the floor, and adjusting those is more or less not an option. So while we aren't opposed to cutting into the linoleum if necessary, we will need to match its height somehow so that the cabinets are at the appropriate height.
There's a cabinet about 20" from the worst joist, which is also where two OSB boards meet. So we can't remove the entire board, but we could potentially cut it back to the previous joist and path that spot somehow. I'm not sure if there are structural issues to worry about here.
One thought we had was to cut out a wide strip of the linoleum along the bad joists, then fill the now-pits to level with the rest of the floor. Self-leveling products sound handy, but my research tells me that there aren't any that work properly on OSB. Plus, I'm not sure if that even makes sense for use in a narrow strip like that. Some sort of thicker, manually-leveled putty also makes sense, but I don't know if anything would work for that purpose.
So I have a good understanding of where the problem areas are and what the result should look like. What I'm looking for is: what combination of steps can we take to level the floor, while keeping the cabinets where they are, the subfloor stable, and not raising or lowing the overall floor height?
*As a side note, we have a spot where we cut out the linoleum to get to a spot where the subfloor has some wood rot. We intend to patch the subfloor here, and so I'd like to handle that in a compatible manner. If you have any insight here, I'd love to here that as well.