I moved into my house and refinished the floors about 5 years ago. Now the stain looks fine but the water based polyurethane that I used seems to be pretty much gone, and there are several surface scratches in certain areas. What is the best method to prepair my floors for new coats of polyurethane without removing the stain that is already there? Do I need to rent a sander and go over the entire floor with a light sandpaper? If so, what grit should I use?

I couldn't find a post with this info, but if you know that this question has already been answered, will you please point me in the right direction? Thanks.

Don't have much time now to explain ... SUPERBOWL PARTY IN PROGRESS ... but do some research on SCREENING. Before you screen make sure you clean the floor thoroughly at least 2-3 time to realy exfoliate old dirt and old cleaning products. If you use the search button above here, enter screen or screening and see what you find.

Will be back soon to read this thread and follow up with better info for you ,,untill then GOOOOO SEAHAWKS!!!!

You may want to start by reading this.
http://www.hardwoodinstaller.com/hardwo ... screen.htm
If you have more questions, feel free to post them.

It sounds like screening is exactly what I need. I do have a few questions that I didn't find with my initial research:

It looks like I rent a buffer and purchase screens, do I also need to rent something to do the edges?

Is there something other than water that I should use to clean the floor before screening?

For the few spots where the stain is worn or the scratch is too deep, can I put a little stain on after screening and before recoating?

I read that the floor should be vacuumed after screening and the excess dust should be cleaned up with mineral sprits. Should I get a sponge and clean the entire floor with mineral spirits?

Am I correct in assuming that I should take the quarter round off?

Sorry for all the questions (I am still searching the web), but I did my floors the first time without any input and I already need to touch it up.

This is the way I recoat floors. Since you originally used a waterbased poly, I'd stick with a waterbased poly. You may want to get a professional quality brand like Bona Traffic or Bona Pacific Strong.
First, vacuum the floors well to get the loose dirt up. Then wash them with Bona hardwood floor cleaner. You don't need to remove any trims but you do need to move the furniture and rugs out. The rent a slow speed (175 rpm) buffer (a 15 or 16" one) and get some 3M maroon "in between coats" abrasive pads. Get some Bona Prep spray and condition the floors with the spray and the maroon pads according to the directions on the prep bottle. It's easy. After conditioning, vacuum and tack again with the Bona cleaner. I use soft cotton rags to go around the edges and a Bona microfiber mop for the field. You want to get all the dust up and the floors as clean as possible. After that, apply the Bona floor finish according to directions on the bottle. THen allow to dry. If deep scratches are not concealed by the recoat, then you can attempt to disguise them with a touch-up marker stain pen but it usually doesn't hide them completely. Good luck.