responds: I am confident that water-based
finishes will perform as well or better than
oil-based products, if the installer takes
the time to master some new application techniques.
Waterborne finishes have been used for years in
high-traffic areas, such as gyms and racquetball
Waterborne floor finishes have a low viscosity
— that is, they’re watery
— so the finish penetrates deep into the
wood. While this increases their durability it can
also create some application problems that
you’ve got to master.
For starters, the finish can really raise the
grain on open-grained wood, such as oak. To combat
this problem, I mist the floor very
lightly with a two-gallon garden sprayer. I
don’t allow the water to pool, and then I
let the wood dry for about 12 hours (check with a
moisture meter to be sure the moisture content has
not been raised). This is sufficient to raise the
grain, which I knock down with a worn screen back.
If you do this before applying the first coat,
you’ll avoid problems caused by excessive
disking between coats.
Because you have less buildup, disk between
coats with a light abrasive pad, instead of a
screen back. These pads are color coded, and green
seems to work best.
Also, coats of waterborne polyurethane are thin
and dry quickly, so it’s important to keep
a wet edge when laying them down. To make this
happen, you may need to add a retarder (ask the
coating manufacturer), and lower the heat and keep
doors and windows closed to reduce air movement
while applying the finish. Then allow the finish to
dry as slowly as possible to cure it. Some finishes
are marketed as quick-dry products, but ignore this
marketing hype. The better the coat is cured, the
stronger it will be.
Michael Purser is a second-generation floor
finisher in Atlanta, Ga.