About the House: The Ins and Outs of Sanding Wood Floors

By Matt Cantor
Thursday January 21, 2010 - 09:46:00 AM

Some things are a bad idea no matter how you shake ’em. Government lobbying, TV shows involving supermodels, and pretty much anything involving a lot of helium balloons and lawn furniture. Oh, yes, and trying to refinish your own floors while your partner is off for the weekend. 

Every once in a while, someone tries to do this to their fully furnished home and the result is not pretty. When you get done, you might end up buying yourself a new stereo, a new computer, phones and having nearly everything else you own, sent out to the laundry. 

This is because floor refinishing, or sanding, produces pounds of extremely fine wood flour. So fine, in fact, that it will easily flow under unsealed plastic barriers and will effortlessly pour under or around doors. Rooms that didn’t seem slightly vulnerable can end up with a fine layer of wood dust on, and inside of, everything.  

Part of the reason that this happens is that occupants and workers are often unaware of the amount that is floating in the atmosphere for hours after work had ceased and may open or remove barriers while the air is laden with this incredibly invasive stuff. 

This is why just about the only task I will recommend be undertaken prior to moving anything into one’s new dwelling is the refinishing of wooden floors.  

You just don’t want to see the results of this avoidable mess. Further, this is a job best left to professionals for a number of reasons that we’ll discuss. 

Sanding wooden floors can improve their appearance greatly but it can also ruin them, permanently necessitating replacement in some cases but, more often simply ending in an plaintive effect that one gets to look at and live with for years on.  

Sanding is most often done using “barrel”-type sanding machines. These have a fat sanding roller that runs at very high speed and can create a wavy floor or gouge a trough in about a second or two of unattended operation. These ma-chines have to be driven at a uniform speed with an appropriate level of grit by a skilled professional to obtain the sweet result we all want. I would much sooner see a homeowner attempt their own plumbing than to try to sand their own floors, though there are finer points to this argument I’ll save for later.  

Sanding is also a very reasonable expense at something like $2 or $3 a square foot. This means that most homes get done for something over two grand (your kitchen and baths get excluded right?) and given the enormous aesthetic improvement and the cost of most home improvement projects, this seems to me to be a really good deal. 

If you do choose to undertake this journey, I’d suggest renting a couple of those moving pods and having them placed on your street for a few days (consider the local parking ordinances or get a special permit from the building department) and just move out. You can fill your kitchen with furniture wrapped tightly in plastic but don’t be surprised if some gets infiltrated by the nasty stuff. This can all be seen as a great opportunity to empty closets and lighten up. Don’t bring everything back in! Donate to your favorite charity shop.  

If you’re buying a house and haven’t moved in yet, this is the time to do this job.  

Consider the tone of the flooring when refinishing floors. My general bias runs toward not staining floors, though the clear finish will always provide some darkening (you can wet a freshly sanded floor in a small area to see what this will probably look like). Most older houses lack adequate fenestration (in English, enough windows. There, I slapped myself) and a light-colored floor reflects more light around the room. Conversely, old, darkly stained wooden floors make for a danker environment (which might be your thing and that’s … OK). 

Oak flooring, the most common in the United States between the late 1800s and the 1960s, is generally quite thin. The standard was 5/16ths of an inch or just over a quarter inch. Installed over a substrate, this results in a net 1-inch flooring.  

This means that sanding can only be performed a limited number of times and you’ll want a professional sanding contractor to evaluate this with you.  

If you pull out a floor register from your heating system or something similar that cuts through the floor, you can gain a peek and see what’s left of the flooring. Most floors will never have been sanded so this is usually not a problem.  

Oak flooring, of the kind mentioned above, is face-nailed with the nails being “set” or recessed just slightly below the finished face. The recessed nails are hidden by a bit of putty.  

This means that when you sand, you’ll be revealing the nail and have to set it again (though I’ve seen many jobs where the nails were left exposed and consider this an aesthetic choice rather than a requirement). When the nails get set again, they will be puttied in and sanded over to conceal. This is where thickness becomes a serious problem because there will be less wood for the head of the nail to grab. The uninitiated can end up with loose planks if they’ve overset nails or sanded one too many times. 

When floors are sanded, they are generally sealed or “finished” with muliple coats of a polyurethane material that is painted over the freshly sanded and vacuumed wood.  

In better applications, the finish is often touch-sanded between coats for a high gloss, but this is not always necessary given the improved chemistries of modern finishes. By the way, gloss is an important issue to consider along with staining and other floor repairs. I prefer low gloss for longevity (glossy floors show scuffing much sooner).  

Also more coats are better and excessive thinning of subsequent coats may save the contractor money but gives you fewer years before the finish is worn away. 

Wooden floors can be repaired to a surprising extent prior to being refinished and most companies that do refinishing can provide excellent repairs. What few can do well and should largely be avoided is the removal of stains. Much of the staining of old oak floors will remain and should be considered alongside your advancing wrinkles as signs of wisdom, experience and individuality (of which you, no doubt, have gobs). 

Today, there seems to be an increasing number of floor-sanding firms that tout “dustless” or “dust-free” sanding. Very powerful vacuums are used (some large ones remain on the truck as in the case of insulation companies and carpet cleaners) to capture all the atmosphere around the machine and keep the house clean.  

Some purveyors of this product show fully furnished homes being sanded on their websites and claim that their workforce can even show up without dust masks. I have no doubt that some percentage of these are able to do what they purport but I would want to speak with a few recent clients (no brothers-in-law, OK?) and also be sure that my workers were adequately experienced (no new guy on my job).  

Every technology gets presented as being flawless and, as we all know, one size never fits all and every flawless system has its flaws. Caveat emptor. 

Now, in my usual fashion, I will overturn my initial implorements and offer a partially poisoned pill.  

If you do wish to sand your own floors, I would strongly recommend avoiding the “barrel” type of sanding machine in favor of the disk type. There are large disk sanders that also drive around the interior but are far less likely to gouge the floor on the first test drive. These take longer to do their job but that’s probably a good thing when you’re starting out.  

You’ll want to a get a full tutorial if you choose to do this and be sure to protect your lungs without mitigation. Everyone on this jobsite should be wearing a respirator, not just a paper mask. The long-range ill effects of this kind of job can be nasty and it’s not worth any savings that might seem to be gained. Trust me. I’m a total cheapskate but I never skimp on respiratory protection. 

Our older housing stock is filled with sublime wooden flooring, much of it hidden by carpeting or by palimpsests of stains, grime and gouging. These floors, even the most mundane, are so beautiful when refinished that they can often transform the simpleist of rooms.  

Many turn out to have extraordinary features such as bordering and knots of darker hardwoods. Some are the tiny matchstick floors that I can’t get enough of. There are even floors that steal their designs from quilt-making with “baby blocks” or “log cabin” patterns.  

Again, you can miss these features entirely if they’re covered or darkly stained and, with a bit of effort, you might find that the job of floor refinishing in your old or new home turns out to be less contracting and more art restoration.