Our examination of popular myths about floor sanding continues! (Read part 1 of the series here.)
“You should always put a coat of wax over every finish coat”
In the 1940s and 50s, the floor finishes that were available were relatively soft. To keep them from getting scuffed easily, they were polished with wax. Wax simply allowed shoe heels to glance off the floor without leaving a mark, but somehow a myth persists that wax is one of the most natural, protective substances you can apply to your wood floors. Unfortunately, this is simply not true.
Wax is soft and can only be applied in very thin coats, which means it isn’t very protective. It water-spots easily and is not resistant to any solvents. Because it is soft, dirt gets embedded easily and is difficult to remove from it, so wax should be stripped off and completely reapplied every year or so. Modern polyurethanes are much tougher and much more water and solvent-resistant, so adding wax just adds work and heartache to your life. Even worse, if you wax your polyurethane floor, you won’t be able to apply maintenance coats of polyurethane because modern finishes will not bond to the wax coat.
“My floors are looking slightly rough and dirty; they just need to be buffed up a little.”
This myth follows naturally from the strong collective memory we seem to have about wax floors. When a wax floor looked a little dull, it could be buffed with a clean cloth, and the friction of the buffing would melt and respread the existing wax and bring back some shine. There are very few waxed floors still out there - most modern hardwood floors have been coated with a polyurethane of some kind. When this kind of finish looks dull and dirty, it is probably because the protective is all worn off and the wood fiber itself is full of foot soil. Unfortunately this doesn’t buff off. Polyurethane is a hard, dry plastic layer. We can apply a fresh coat of polyurethane over the existing layer if we want to bring back the sheen, but if you simply run a buffer over a polyurethaned floor, you will actually scratch the plastic coat and make it more dull.
“I just left a huge scratch/dent/gouge in my finished hardwood floor, so I’m just going to pack it with wood filler, sand it, and coat over it”
Back in the fifties, when there was only one type of finish used on hardwood floors, you could fix a scratch with the method described above and probably do an adequate job. But harder, higher-building film finishes make spot finishing over repairs much more difficult, especially if you don’t know what type of finish you are repairing. And using wood filler on any area larger than a pencil eraser will be more noticeable than the dent itself, no matter what era your floor finish is from.
If the dent or scratch is small enough to fill, here’s what you should do:
1. Tape off the edges of the boards that are affected by the scratch; you can’t just sand the irregular area around the scratch itself or it will show.
2. Sand to bare wood in the area inside your taped lines.
3. Fill your void with filler and let it dry. If you have thrown caution to the wind and are filling a deep hole, it will require several applications and more dry time.
4. Carefully sand the filler flush and wipe clean with a dry cloth or microfiber.
5. Finally, apply finish to the bare floor, being careful to stay within the taped lines. Since you’ve sanded the floor to bare, you’ll need to apply more than one coat - preferably three. Be sure to use the same kind of finish that you removed from the floor! If you removed an oil-modified urethane (which is pale amber) to make the repair and replace it with a waterborne urethane (which is crystal clear), for example, the newly fixed spot will be much lighter, as shown in the photo below. Read more opinionated opinions about filler here.
Got questions about your own beliefs about hardwood flooring - and not sure if it's a myth or truth? Contact Pete's!