My vote is to sand and refinish the existing floor, but we may be getting brand new hardwood, which I believe means I need to tear up the old hardwood floor. I just wanted to see if anyone knows why I have these two complete floors, and if there's anything I need to be concerned about or be cautious of when potentially ripping up the old floor.
I have PICTURES and questions that relate to them. If the URL's below aren't links you can click on, just copy/paste the URL into your browser.
The above is a picture looking into the cold air return. As you can see, the Sub Floor is coming in from the wall diagonally, running across the seams of the top hardwood floor. HOWEVER, look at the following picture in the SAME cold air return:
In this picture, you see that the same sub floor that is diagonal pieces coming in from the wall is actually STRAIGHT pieces after only a couple inches in from the wall. The surface you see under the subflkoor is just some plank that's covering something, I don't know what yet. Look at the right of the pic; those pieces run diagonally, you can see from the seams between pieces. Now look at the top of the air return hole; those pieces run parallel with the top hardwood pieces! Does this indicate that the subfloor USED to be diagonal, but then someone cut it all up and replaced it with straight subfloor, leaving the diagonal pieces jutting out a little from the sides?
Now here's the view from the basement steps, looking back up towards the top; it shows the level of the floor upstairs, and then the joists that you can see in the basement (you can see from the distance between upstairs' floor and the ceiling joists in the basement that the basement joists are not the same ones seen through the cold air return upstairs):
Now, in the last pic, I'm looking up at the ceiling in the basement. You can see the cold air return duct on the left, the diagonal pieces that make the ceiling (NOT the subfloor of the upstairs), and the joists that can be seen from the basement:
So, does anyone know why I have two sets of joists and subfloor, one on top of the other? I've been to look at 3 old houses around town, and they just have a floor, subfloor, and joists, and the joists are the same ones you see in the basement. In my house, I have a floor, subfloor, joists, then more floor, then more joists. The house was built in 1929, and is plaster walls/ceilings, if that helps anything.
So, to sum up:
1) Why do I see diagonal subfloor pieces that stop and are replaced with straight-running subfloor pieces upstairs? And does this add serious complications to the idea of tearing up the top hardwood floor?
2) Why do I have a "double" floor, like a set of two complete floor assemblies (subfloor and joists on top of subfloor and joists)?
3) Does anything described and seen in the pics mean that I'm in for a world of hurt in terms of tearing up hardwood and putting in new?
Thanks, everyone, for reading, for your input and thoughts, advice, cautions, etc.