Yes. I have sanded and finished subflooring for customers. Really no different from any other flooring finish work, except that you have to consider the fact that it happens to be a single construction floor system and, therefore, you have to take steps to protect what is below the floor when you sand and then apply stains and finishes. Anything you do above to the floor surface can easily find its way down to the space below...dust, stain and finish. You have to sink any top nails below the surface of the wood before you sand and continue to punch them below when necessary. You probably can never remove all tar paper lines and staining, but that is OK, as the floor will have a great look all by itself. I have finished these natural and stained a few. I also colored one green once at a customer's request. That one was unique and beautiful.

This post has come to life again, so for anyone seeking it out because they have the same problem, I wanted to jump in with some personal experience. After the oak floors in our new-construction house began cupping and buckling (the builder had rushed the build, since he was trying to finish a spec house on the same deadline, but had since decamped to another state due to a sex scandal), we saved for a few years and replaced it with engineered cherry flooring. This probably would have been about the same time as the OP's post, which as of this comment is 13 years old; the manufacturer was a Swedish company called Kährs, and since our local distributor had just started carrying it, there were no red flags in terms of bad reviews or negative customer feedback. That cherry floor looked great--for about ten minutes. EVERYTHING scuffed and scratched it. A puppy just innocently living its life? Scratches galore. Someone dropping anything heavier or sharper than a pillow? A guaranteed ding. A kid running a toy car over it? A tell-tale track of scuffs. Anyone wearing shoes (and I'm not talking stilettos)? Scuffs, scratches, and dents. It was ridiculous, like, we couldn't believe how quickly and easily the floor accumulated damage. Whatever finish was on that cherry, it did absolutely NOTHING to protect against ordinary wear and tear. We tried everything to clean, protect, and rehabilitate that floor. Shoes, even slippers, became forbidden in the house. We had a network of rugs from one end of the house to the next. Every chair not only sat on a rug, it had felt floor protectors and ugly wool socks on its feet. We swiffered like mad. For ten years, all the measures we took were futile, and just ended up causing us added aggravation and frustration. Finally we gave up, realized we were going to have to bite the bullet and install our THIRD hardwood floor in fifteen years, and replaced every square foot of the cherry. This time, we went for a harder wood (hickory), though the major problem with the Kährs had obviously been the finish. We put in a fairly pricey but beautiful hand-scraped wide-plank floor (Baroque Flooring Bavarian XL) and it was FABULOUS--everything the Kährs wasn't. It was gorgeous, it was tough as nails (pets were no problem!), and it was easy to clean. The moral of this story: Sometimes there's just no way around a bad product, except to replace it. The sooner you can afford to do it, the happier you'll be.

Poly does not touch up at all well. The entire floor will need to be sanded and recoated, and you will still see the line where you stopped at the threshold. In addition, some of these paint remover products or floor cleaning products that you have used will impair adhesion of the new to the old. If that happens, it may look OK at first, but then start peeling off in a couple of months. If that happens, the only recourse will be to sand to bare wood and start over completely. If you've ever used anything with silicone or orange oil in in on the floors, skip the intermediate peeling step and sand down to bare wood now.

I just wanted to thank you all for taking the time to answer me. Your responses really helped. The wood floors are all original oak, except for in the kitchen, where we think they are pine (and never meant to show, but we stripped them anyway!) I actually have high gloss finish in the kitchen, by accident. See, we did the LR and DR floors in 2001 and used semi-gloss and a medium stain. In 2003, we did the kitchen and stripped the floors and I bought high-gloss poly by mistake, and didn't realize it until it dried! I do like it, very much. But I just wondered, in that big expanse of my LR and DR, would the high gloss finished be too much gloss, know what I mean? My instincts tell me to go for it, but I still have some doubts. We definitely need a new topcoat, though. I don't want to ruin the floors! I did cover up the floors partially in the LR when my daughter started to walk. It's just a carpet remnant, no pad underneath, but I think I should keep it for the kids for now. I wasn't thinking how the hardwood floors would work out with babies! Here are some updated pictures of the house. Since I took those pictures on the pbase site in 2004, we've done a few more updates - new fence, stripped/sanded/painted the front porch gray (and I'm still working on the trim, that's why there are no new pics of the front porch - but it looks so much better!), and totally finished the basement. WHEW! And two babies in that time, too. :) Thank you all for your complements and opinions! I think I might try the high gloss. Here is my site with the older/remodeling pics: http://www.pbase.com/yellowduck and here are the current house pictures, minus the front porch: Here is a link that might be useful: The house