Polyurethane works by building up multiple layers of plastic over your wood floor.  These layers form a very effective solvent barrier, and they take the brunt of the day-to-day wear on your floor, since the wood is essentially encased in a clear plastic shell.  Unfortunately, that plastic shell obscures the texture of the wood grain itself and sets up the unreasonable expectation that hardwood floors should always look as smooth as a lake on a windless morning.  But they shouldn’t.  Much of the beauty of wood comes from the texture of its grain. 

The current emphasis on more and thicker layers of polyurethane (and other polymer finishes) is creating a generation of wood floors that look more like sheet vinyl.  By trying to eliminate all minor scratches and evidence of everyday living, these floors are taking on an artificial look and losing their ability to reflect the natural patina of living that enhances their beauty.

There is another option—a compromise that allows you to protect your floors while still appreciating the texture of the wood itself: a tung-oil blend called Waterlox.  Even though the name contains the word “water,” this is not a water-based product; it is a penetrating resin-oil finish.  Its main component is tung oil, which R. Bruce Hoadly in Understanding Wood describes as “an aromatic, natural drying oil obtained from the nut of the tung tree.”  Tung oil has been used as a wood sealer for centuries in China precisely because wood absorbs it so readily and because it does eventually “cure,” meaning that it hardens when exposed to oxygen.  Essentially, tung oil works by seeping into the wood and hardening, which, on a floor, allows the wood grain itself to take the wear of foot traffic.  However, straight tung oil is neither as hard nor as solvent-resistant as polyurethane. In Understanding Wood Finishing, Bob Flexner states that, “Tung oil can be made fairly water-resistant after five or six coats.  But it is too soft and thin to resist scratching or water-vapor exchange and it is difficult to make the finish look nice… In addition, tung oil cures very slowly, and it turns white if left to cure in any thickness…so you need to wait several days between coats.”

Waterlox solves some of the problems associated with pure tung oil by adding resins that cross-link and harden, forming a better barrier against the cola that will eventually be spilled on your floor.  Yet the added resin is not so much that it builds up excessively over the wood grain itself.  The fact that Waterlox penetrates into the wood, rather than building a film on top of it, makes it easy to spot-blend additional layers.  Polyurethane floors, because they act like layers of Plexiglas over your floor, need to be recoated fully from wall to wall—trying to touch up a small area will leave distinct lap marks. Maintenance layers of Waterlox, however, can be rubbed selectively on your floor.  If you see a small area beginning to show wear, a spot-coat of Waterlox in that area will blend and seamlessly restore the protection in that area.  This can be a major benefit if it allows you to leave your grand piano or big-screen television in place and still maintain your floors properly.

The main drawback to Waterlox is that it is solvent-based, meaning that your home will smell of evaporating paint thinner during parts of the coating process, which can take three to four days (dry time is up to 24 hours between coats, depending on temperature and humidity).

 Waterlox Tung Oil advantages outweigh these minor problems.  Waterlox bonds well to itself, so you are not required to abrade the floor between coats unless you are experiencing roughness or grain whiskering.  Another Waterlox feature is that it can be tinted with up to one quart of old-fashioned, solvent-based stain (without additives such as urethane) per gallon.  Customers who are trying to recreate the color of aged shellac on maple, a species that does not take stain well, have had success using this method. 

The sheen problem is easily solved by simply waiting for six months.  Foot traffic will eventually soften the high gloss of the original sealer to a soft satin.  If you can’t wait, you can buy a separate Waterlox Original Satin finish that will give you the lower sheen without the wait. 

Waterlox also comes in a very high solid-content formulation that is sold as Waterlox Original Marine finish.  It is more expensive than their Original Seal product, but it is designed to resist UV rays, freshwater, and saltwater. Modern polyurethanes that are formulated for exterior use (porches, outdoor steps, or thresholds) can be disappointing because they break down and peel, usually after one winter’s worth of exposure, especially here in Minnesota where snow can sit on your steps for four months.  Because it is a penetrating finish and can’t “peel,” Waterlox Marie performs better on exterior applications, though we do rub on an extra layer every fall just to be safe. 

Ideas and some text Courtesy of Pete's Hardwood Floors

Do you have dogs?