Sanding Saga

Our most ambitious pre-move-in project in our new house has been to remove the carpets and refinish the underlying hardwood floors. I'd like to discuss how it has gone for us, from can-do optimism, to despair, to surrender (we hired some help). I was remiss in not taking pictures throughout the process (I kept forgetting the camera), so all I can give you is this post-carpet, pre-sanding photo. Later, after I discuss staining, I'll show an after photo.

You can see wear down the center of the photo, in the high traffic area. You can also see some yellowing of the wood.

I rented an orbital floor sander from the local rental place. All sanders I saw in how-to articles had 3 sanding discs on the bottom, but this had one big rectangular pad (the sander looked something like this). The rental place also gave me a bunch of sandpaper (of grits 20, 36, 60, 80, and 100), and said I would not have to pay for what I didn't use. Note: these sanders are quite heavy.

Before sanding, I shut the bedroom doors and put newspaper under them. I also taped over the outlets and hung a sheet of plastic between the dining room and kitchen. These measures were intended to keep dust out of these places. I also donned safety glasses, a dust mask, and ear plugs. Previously, I went over the floor a few times to make sure I removed all carpet staples and nails. We did not remove our baseboards prior to sanding.

I started sanding with 36-grit paper (smaller numbers mean coarser paper), sanding primarily with the grain of the wood, although the rotation of the sander means it goes across the grain half the time.. The first pass revealed a large number of 6" by 1" slight depressions in the floor, perpendicular to the grain of the wood. I thought these might be relics from a previous drum sanding job gone bad (note: besides the orbital that I rented, drum sanders are the other type available. These sand more effectively and efficiently, but in the hands of an amateur, these can cause damage to the floor due to excessive sanding). I also found some wide scratches that I had not noticed previously.  Apparently, floor finish can really hide some flaws in hardwood.

I had a heck of a time with these depressions. The sander had little effect on them. I tried using the 5" palm orbital sander I had on hand, but it also had little effect, as did sanding by hand. I also found that the area a couple inches out from the wall, all the way around the house, was similarly impervious to my efforts. I knew I needed to get the finish off of these spots, or they would stick out when I tried to stain the floor.

After doing two passes with the 36 paper (one at a 45 degree angle across the grain), two 60 passes, a 20 pass (I was desperate), another 36, and two 80 passes, I thought the floor was acceptable. The finer sandpapers are intended to remove the scratches put in the floor by the coarse paper, and give the floors a smooth, even finish (I should note here that I vacuumed the floor after each pass with a shop-vac to remove dust). I should also note that I generally used two sheets of sandpaper per pass, with each pass covering about 450 square feet. There appeared to be some color left in the wood, but I thought I had removed enough material that I could stain over what was left.

But then I rented the edger, and found out I was wrong. The edger is a foot-tall unit that uses one 7-8" sanding disc that is attached to the unit by a bolt. When operating it, only one side of the disc actually touches the floor. The edger, which spins at a high rate of speed, instantaneously reduced my edges to white bare wood, in stark contrast to the rest of the floor, and the numerous passes I made over it. I was tempted to use the edger to do the whole floor, but that would have taken days and killed my back.

So I decided to try a 3-disc edger, thinking that maybe the sander I had rented was the problem. Lowe's carries such a sander, so I rented theirs. Note: while the sander I first rented did a very poor job of picking up dust, despite having a vacuum attachment that is supposed to do just that, the Varathane from Lowe's does great in this regard. This sander worked well for about two minutes, then seemed to do nothing. It was as if the sandpaper only worked when brand new (it turns out this was the floor's fault, not the machine's). With this sander, I managed to feather the edges of the floor, so the contrast between the white edges and the light brown rest of the floor was not so stark. But it still didn't look right.

At the beginning of this process, we got a quote from a company to see what it would cost to have someone else do this job. The quote was quite high. But after renting the Varathane, we decided to get another quote, to see what it would cost just to drum sand it. I thought about renting a drum sander myself, but didn't really want to mess with one of those.

The quote we got wasn't too bad, and we wanted to get this done, so we bit the bullet and hired a local company to do it, and the floors ended up nice and white in short order. My ego was assuaged by the fact that the owner of the company confirmed that there was drum sander damage on the floor. He also said there was something weird with the finish on our floor, so he had to use more sandpaper than normal to get the job done. This made me feel good, because all the how-to's I read made sanding seem easy and straightforward, but that wasn't my experience.

That wraps up the sanding part of the job. Here are some links I found helpful.

Next, I will discuss staining, a much more successful endeavor.