You need to do a little more archeological digging still. You need to know the whole construction of the floor before you can decide how best to install something new. I'd take up that plywood piece in the kitchen and see what's under it. It's higher than the surrounding floor, so needs to go. You should also be able to see from there what subfloor is under the original kitchen hardwood. It's too bad the space under your entryway is finished, but I'd still do some exploring from below to see what's under there, and to figure out the fix to stop it from squeaking. Is it drywall below or a drop ceiling? I know it probably seems like a pain to tear out drywall, but if you cut out a clean patch, like 2' x the width of the joists, it'll be relatively simple to repair. Just make sure to cut it down the center of the joists so that there's room to screw the patch piece to it later. Cut the hole under the area that squeaks the most, if you can. Have someone walk on and watch the floor from below to see what's moving. It might be as simple as pounding in a couple shims from below, or face-nailing a loose board from above. You want to find out what's underneath the hardwood. It might be laid directly on the floor joists, or there might be 10" wide boards that the hardwood is nailed to. Another thought is to take out a board in the hallway, since that's not original and you want to replace it. See what the subfloor is there. I am a bit puzzled at why, when you've stripped the kitchen down to the original hardwood, it's still higher than the hallway floor. Is your current surface perhaps not the original kitchen hardwood? Peeling back the plywood area will help determine that. BTW, I haven't heard of that stop squeaking product you linked to, so can't offer any personal opinion. And don't pour self-leveling compound over top of hardwood. It needs to go over plywood.

My brother is to the stage that their house built in the mid century is now ready for new wood floors. They live in the Los Angeles area, and a TV movie was filmed in their house. (They had to move out and were put up free in a hotel with lots of room service.) The house was painted and then all the downstairs was refinished for them to move back in. When the production crew sanded the floors to revarnish them, they noted that they were now sanding down to the nails in the flooring. So they knew that the next floor redo would involve just installing new flooring. They are getting ready to do just that 15 years later. So if you can sand the floors and not find yourself exposing the nails, then you will be fine. I grew up in a 50 year old house and my dad had the oak floors refinished, and they looked great. Original to the house installed wood floors should last through several sandings.

I think it's a no brainer. Have the floor scraped and refinished. The new finishes they have these days are so tough, all you need to do is damp mop them to keep them clean. If, after you scrape the floor, you see a big difference in appearance between the periphery area that had been painted and the rest of the area, you can probably deal with that by staining the whole floor a very dark brown which will hide those differences. The other option, if the hardwood is thick enough (and in an older house like yours, it probably is) is to scrape some more to come to the "raw" wood. Scraping and refinishing is a messy job, and probably more expensive than painting. But it is much nicer looking and will last much longer and be easier to maintain, so will be cost effective in the end.

Hee hee! Who knows, with a whole upstairs of hardwood- I may just dance! But we have a three bedroom suite complete with kitchen downstairs, and we would like to keep our options open for future plans- perhaps a B & B, perhaps grown kids moving back for a while, maybe renting out to a student. But even just for house guests_ when I sleep in the basement at my sister's or my Mom's, it sounds like a herd of elephants when people wake up and walk around in the morning. Not a pleasant way to wake up! One of the boxes was crushed by the forklift, so we opened it and 'read the directions'. Amazing- told us NOT to open the boxes, how would you know unless you opened a box!!?!! Anyhow, in the instructions it does say to lay down roofing felt or tar paper for noise reduction and moisture control and for cleanliness. So, hubby is off to HD to buy another roll of tar paper, and I guess we'll leave it for the installers to lay down tomorrow morning. Almost 8:00pm, and we've just finished laying down subfloor for hallway and haven't had dinner yet. Thanks for the input. P.S. What you call roofing felt- is that the same thing as tar paper?