Floor refinishing, wood bleach

I think it's safe to say we did not know what we were really getting ourselves into. Then again, we rarely do. A month seemed like enough time. Professionals can do it in 5 days, so a month seemed like a pretty good buffer. That said, we got so close, oh so close, but we had to call in some help at the end. Ah well, can't win them all.

Lets see, when we left off last, we were talking about flooring and replacing boards. Which we did in multiple places, most notably in the corner of the living room.

Now, because this is (obviously) a lot of work, we thought we would try a different approach on some of the spots that seemed less terrible. For example, this one in the middle of the living room:

Now, I now it doesn't look like much, but this is after at least one round of sanding down to bare wood, so believe me, when you put poly back over it, it would be noticeable. Since this one, like the one above, spanned a number of boards, we though we'd try using wood bleach to even the tone. We read about it online, and it seemed like a good idea. Unfortunately we neglected to read the fine print on the bottle that said it had to sit over night and more than one application might be necessary. By this point, we were riding pretty close to our deadline for applying poly, but we thought we'd give it a go anyway. here's a shot of the application:

And the after:

As you can see, it did lightened the boards some, but just not enough to really make us feel confident that you wouldn't be able to see it in the final product. So, being the perfectionist we are, we decided to pull up all those boards and replace them. There just wasn't time to keep trying. But hey, you win some, you lose some. 

A word of advice for the future. After much research online, it seems that black stains are generally caused by pet urine and are EXTREMELY hard to get out, even with wood bleach. The urea in the urine reacts with the tannin in the wood (fun fact, in the old days this was part of the process used to tan hides). The long and short of it is that if you have damaged boards that are white in color, it will probably sand out, but if its black, you will probably have to replace them. Our boards were definitely that way, and its good we didn't try to sand it out because after we took them out you could see the depth of the stain into the board, and it was a good 1/8 inch. Way too much to sand out.