How to Sand and Finish Wood Floors
It never ceases to amaze me that something as rough as sandpaper can render raw wood flooring so perfectly smooth and in plane. It extra-amazes me (if someone can be “extra” amazed) when you load the heavy-grit stuff onto the heavy-weight, high-power sanding equipment to bring a raw floor surface from rough to ready.
What also befuddles me is that I tackled this job myself.
See, as a contractor, I almost always subcontract floor sanding out to a specialist contractor. Usually they can do it better, cheaper and faster than me or my crew, especially on large projects. However, this particular floor had a time budget that was running low, and rather than wait weeks for a contractor to find a hole in his schedule, I rented the equipment and tackled the job myself.
While I’ve sanded floors before, I learned some things on this one that can save a few headaches.
Note: You’ll notice that the floor shown in the step-by-step portions of the article is not a standard floor. Instead it’s top-nailed, wide plank Douglas fir barn boards. That means the photos may not look exactly like the T&G red oak or maple usually found in residential flooring, but the techniques are the same.
Preparation and Timing
Prepping a room for sanding, in my experience, is about bracing for a dust storm—both in the room to be sanded and throughout the house.
Dust. First, the room you’re sanding must be empty, i.e. everything off the floor. Some sanders kick up a lot—and by a “lot” I mean a LOT—of very fine dust. That means it will settle on every shelf, picture frame and knick-knack. It may even float through the house, which is a problem you simply don’t want to have, especially if you’re remodeling an occupied home.
Take everything that’s not nailed down out of the room. It will be faster than dusting it all and/or cheaper than hiring a maid after the fact.
Indeed, the dust collection in the sander I rented failed halfway through sanding my floor, so I not only had airborne dust, I had piles of it on the floor. Ugly. I also suggest renting or buying an air cleaner. Stick it in a doorway or somewhere else out of the way (and off the floor, of course) to chow down on dust. They work great funneling airborne particles.
Molding. It usually makes sense to remove and replace the shoe molding if you can. You don’t have to, but chances are you’ll hit the existing molding with the edge sander and have to fix it anyway. Plan for this. One trick is to replace painted shoe molding with a shoe that’s the same species as your floor and you then finish it to match the floor. This is faster than painting and looks nice.
Timing. Be ready for the prep/sanding/finishing process to take more time and be more physically taxing than you think. You may have problems with the finish or even the rental equipment itself, which happened on my project.
Start with the roughest grit paper–a wood-gnawing 20 grit.
A mix of specialty and common tools are the requirement d’jour for getting the job done.
Of course you’ll need to rent a drum sander (a tool I liken to a lawnmower for floors, except that it’s a lot heavier) and an edge sander (an orbital sander on wheels that looks like it mainlined sander growth hormone).
You’ll also need a broom/dustpan combo, a good shop vacuum, and a heavy-gauge extension cord. And then there’s the various and sundry hand and power tools you’ll need for stuff like replacing the shoe molding, setting a nail or two, etc. Having a 6-inch random orbital sander is pretty handy, too, especially if you’ve got stairs to tackle. Make sure you get some seriously gnarly grits for that tool before sanding. The typical selection I’ve seen at home centers aren’t nearly aggressive enough for the heavy work of removing a floor’s finish and/or heavy stock removal.
You’ll also need paint brushes, the finish-appropriate applicators/handles, pails and mineral spirits for the finish and cleanup.