migrates through the smallest openings, so use
painter’s tape to seal the perimeters of closed
doors and keyholes. Because baseboards will get
bumped by edgers, remove them—though often
that’s not possible. Alternatively, you can use a
metal shield to protect trim, as shown in the top
left photo on p. 568. Vacuum the floor so you can
survey it closely for nails sticking up and floor-
boards that are split or uneven. Use a nail set to
sink nails below the floor surface. If boards are
uneven or cupped, you may be able to sand them
down evenly if they are solid wood. If any boards
are split or splintered, replace them now.
Before you start sanding floors, cover cabinets, air registers, and other fixed
elements with plastic sheeting. To seal edges, use blue painter’s tape to avoid
lifting off paint or cabinet finishes, but remove the tape as soon as possible.
edger; both use the same grit on each pass. To
screen the floor before finishing, buff with
100-grit screens backed by a nylon backing pad.
To smooth between coats, use a 220-grit screen
or hook-and-loop sandpaper strips that attach to
the buffer pad.
Note: If floors are coated with paint or wax—
which gum up sandpaper quickly— use open-coat
sandpaper for the first sanding pass. You can use
regular closed-coat sandpaper (most sandpaper
is closed coat) for subsequent passes.
If you’re simply recoating a finished floor, you
probably won’t need a drum sander and an edger;
a buffer with a nylon pad and two grades of
screen (100 grit and 220 grit) should do the job.
Again, check your floor finish’s label to see what
To prevent sanding over the cord, keep the excess
looped over your shoulders. Drum sanders sand
grit sandpaper to use between coats. Finally,
whether you’re going forward or backing up, so as
sandpaper wears out quickly, so get more than
you back up, continually pull the cord away from
you think you’ll need. Most rental companies will the path of the sander.
566 Chapter 20
replacing a Floorboard
to remove a damaged board, drill holes across it so you can pry it out in
splinters, using a hand chisel. or you could cut into the damaged board by
Bottom leg of
using a circular saw set to the depth of the flooring and then pry out pieces
groove removed
with a flat bar. to make this pocket cut, rest the heel of the saw on the floor,
pull back the saw guard, and slowly lower the front of the saw sole until the
turning blade engages the wood. Be careful: Holding a blade guard back is
never advisable if you can avoid it, and the saw may jump when it engages the
wood. let the blade stop before you lift the saw.
Find a replacement board that’s similar in color and grain: try to pull a
board from a nearby closet or from a floor section that’s usually covered by an
appliance. Hold the board next to the hole and use a utility knife to mark off
the appropriate length. to make the replacement fit more easily, slightly back-
Subfloor
bevel its lower edges on a tablesaw. if the stock is tongue-and-groove, use a
tablesaw to cut off the lower leg of the groove. apply construction adhesive to
To insert a replacement board into an existing
the underside of the new board, then drive it into the opening using a piece of
tongue-and-groove floor, use a tablesaw to
scrap to cushion the hammer blows. it’s not possible to nail the board through
remove the bottom of the groove. Slightly
its tongue, so predrill and face-nail two 6d-finish nails at either end. use a
back-cut the ends of the new board so it will
nail set to drive the nails below the surface. Fill the holes with wood putty.
slide in easier.
Sanding FloorS
A quick review: Shut off all pilot lights, seal off
doorways, open windows for ventilation, wear a
zzzzzz overlap Sanding Passes
FIRST PASS
respirator and ear protection, and start with the
Overlapping passes
Two-thirds floor length
least aggressive sandpaper. If that grit isn’t cut-
Starting point
ting it, you can switch to a more aggressive sand-
paper. Remember: Lower the sander drum only
when the machine is moving.
Start sanding with the drum sander. Sanding
with the direction of the wood grain cuts less
aggressively and minimizes scratches that must
be sanded out later. However, if there are high
Sanding
direction
spots that need to be sanded down or if the floor
is painted, sand diagonally to the wood grain on
the first pass, then with the grain on all subse-
Overlap sections
quent passes. (The diagonal angle should be 15º
slightly.
to 30º from the direction of the floorboards.) If
you must sand the first pass diagonally, use the
same grit on the second pass, as you sand with
the grain. Because a parquet floor has grain run-
ning in various directions, sand it diagonally on
One-third
floor length
the first pass, too.
Using an edger.
SECOND PASS
After completing each sanding
pass with the drum sander, use the edger to sand
along the perimeter of the room, as close to the
Start along a wall and sand about two-thirds the floor length.
base of the walls as you can get. Use the same
Sand up and back. Then raise the drum, and roll the sander
grit sandpaper that you just used on the drum.
over so the next pass overlaps by roughly half a drum-width.
When it’s upright, the sander disk moves in a
Sand until you reach the opposite wall. Then turn the sander
clockwise direction, so work from left to right,
180° and sand the remaining third of the floor.
keeping the edger moving constantly to avoid
scour marks. You don’t need to press down on
Flooring
567
Edgers sand right up to the base of a
wall, but they are aggressive sanders
with plenty of torque. To avoid
scuffing baseboards and casing, cover
the edger bumper with masking tape
or, if possible, have a helper shield the
woodwork, as shown.
Hand-scrape the areas the edger can’t reach. Scrape
with the wood grain, before sanding lightly with a
sanding block.
the edger to make it work. If the edger is sanding
too aggressively, switch to the next finer grit. If
it’s not sanding aggressively enough, change its
sanding disks more often. Again, try to sand with
the wood grain as much as possible.
Finish up by hand. Hand scraping and sanding
take care of the areas the edger can’t reach, such
as in corners and under cabinet toekicks. It’s
hard, tedious work, but fortunately there’s not
much of it. A sharp scraper will speed the job,
scraping with the grain to remove the old finish.
Then use a sanding block to smooth out the
semicircular edger marks. ( Note: If there are a lot
of edger marks, use a random-orbit sander to
feather them out.) Once you’ve drum-sanded,
edged, and hand-scraped the room, vacuum it
well before switching to the next-finer grit and
sanding the floor a second time. If you need to
fill holes or gaps in the floor, do it before the
second sanding.
SCrEEning FloorS
After you’ve drum-sanded and edged the floor
with 100-grit sandpaper and vacuumed it well,
use a buffer with an abrasive screen to smooth
out any remaining marks. Use a 100-grit or
120-grit buffer screen, which is held onto the buf-
fer pad by friction. Because the buffer rotates
slowly and the screen is flexible, you can buff
right next to the base of the wall. Start along a
wall, moving the buffer from side to side (it
rotates in a counterclockwise direction). As you
did with the drum sander, overlap passes about
one-half the width of the buffer pad. Buffer
screens wear out quickly, so replace them when
you’ve screened one-third to one-half the floor.
Save at least one used screen so you can fold it
Between finish coats, screen the floor to improve adhesion, using a 100-grit or and use it to hand-screen the corners where the 120-grit screen. Before applying the next coat, vacuum and dry-mop the floor buffer couldn’t reach.
well with a tack rag.
568 Chapter 20
To achieve an even smoother finish, vacuum
Wood stains penetrate and don’t really seal.
the floor and wet-sponge it with clear water the
When they have dried, penetrating sealers are
night before screening it (the moisture will raise
often waxed to make them more durable. But
the grain slightly). The next day, when the wood
waxed floors are durable only if they’re regularly
is dry, screen it smooth. Wetting the wood and
maintained, which takes time. Thus most floors
then screening it is called popping the grain.
today are sealed with surface finishes, which
P R O T I P
Popping is optional but strongly recommended if don’t require waxing.
you’ll be applying a water-based finish. After
Surface finishes, as their name implies, form
screening the floor and touching up corners by
a tough exterior shell to resist scuffs, scratches,
if you’re using a water-based
floor finish, apply a water-based
hand, vacuum the room thoroughly and use
and moisture. The earliest surface finishes were
sealer first. Sealers help topcoats
clean tack rags to remove dust from any horizon-
shellac and varnish, which have been largely
adhere, deter stains, and seal the
tal surface. (A tack rag is a slightly sticky cheese-
replaced by oil-based and water-based polyure-
surface so you can apply thinner,
cloth pad that attracts dust.) Finally, dry-mop the thanes. Shellac has poor water resistance and
more uniform topcoats. Follow
floor, wrapping the mop in a clean cloth lightly
chips easily, and varnishes tend to be strong
the manufacturer’s guidelines to
dampened with the same solvent you used to thin smelling and slow to dry. Besides, both are
make sure the sealer is compati-
the floor finish.
extremely flammable. Although surface finishes
ble and that you use the correct
require less maintenance, their disadvantage is
grit between coats.
SElECting a Floor FiniSH
that they can’t be touched up when they become
worn, so you must refinish the whole floor.
Floor finishes are often divided into two catego-
Surface-finish sheens range from matte (little
ries: penetrating sealers (penetrants) and surface
shine) to satin to semigloss to gloss. In general,
finishes. Penetrating sealers usually contain
glossier finishes are harder, more durable, and
plant-based oils, such as tung oil or modified lin-
more water-resistant.
seed oil, and soak into wood fiber. In time, they
As you’ll see, polyurethanes vary greatly in
harden to seal and protect the wood. Because
ease of installation, drying time, and durability.
penetrating sealers form a hard outer shell, they
Water-based polyurethanes are the stars of the
can be easier to touch up by sanding lightly and
show these days: tough, nonyellowing, relatively
adding more sealer if wood becomes scuffed or
mild smelling, and fast drying (two to six hours).
scratches—touched-up areas won’t be obvious.
Finishes, Cleaning Solvents, and applicators
finish
cleans with
aPPlicator
comments
water-based
Soap and water
Synthetic brush; pad;
Probably best all-around finish for nonpro; tough,
polyurethane
round applicator
water-resistant finish; easy cleanup, low smell;
work fast, overlapping edged areas before they dry
oil-based
Mineral spirits
natural-bristle brush; tough, durable finish; favored by pros because it
polyurethane
round solvent-resistant
dries slower than water-based; slightly stronger
applicator
smell while drying
Penetrating sealers Mineral spirits
lamb’s wool applicator, Slow to dry; strong odor; scratches easily but can be
(tung and modified
natural-bristle brush
touched up with new finish over old; usually waxed
linseed oils )
stain-sealers
Mineral spirits
Varies: natural-bristle Same profile as penetrating sealer; finish must be
brush to clean rags
waxed to protect wood
Varnish
turpentine
natural-bristle brush; Volatile; strong smelling; slow to dry; hard, amber
or paint thinner
lamb’s wool pads
finish gives historical appearance; often used to
match older finish
shellac
denatured alcohol natural-bristle brush; Poor water resistance; flammable; chips; rarely
lamb’s wool applicator
used for floors anymore
Various (acrylic-
Proprietary
Computer-monitored
Factory applied in highly controlled environment;
impregnated; acrylic-
solvents
sprayer
durable; water-resistant coatings on prefinished
urethane; uV cured)
wood flooring
Flooring
569
Start each coat by cutting an edge
around the floor’s perimeter and
along cabinet bases, using a brush or
a paint pad. Then use a T-bar
/>
applicator to overlap the edged
borders while they’re still wet.
For newer, water-based polyurethanes, use a round synthetic T-bar applicator like this one. Pour the finish onto the floor, then spread it in broad sweeps—like window washing with a squeegee.
And brush cleanup is easy with soap and water.
Because they contain lower levels of VOCs,
water-based polyurethanes also are safer to use.
Despite their volatility, oil-based polyurethanes
are often applied by professional refinishers
because they’re slower to dry and thus allow
more time to even out coats. Although solvent
based and stronger smelling, oil-based polys are
more durable and water-resistant, and they turn
a handsome amber with age. Let them dry for
24 hours before recoating or walking on them.
Moisture-cure polyurethanes are the most durable
of the lot, but because they must absorb moisture
from the air, they’re temperamental to apply,
slow to dry, and best left to professionals.
Finally, there are surface finishes that require
highly controlled environments and thus are fac-
tory applied to prefinished flooring. This group
of finishes may include aluminum-oxide, titani-
um, or ceramic additives to resist abrasion and
may require UV curing, rather than heat curing.
Some of the toughest of these finishes infuse
acrylic into the wood cells in a modern version of
a penetrating sealer.
Use a lamb’s wool applicator to apply penetrating-
oil finishes.
570 Chapter 20
aPPlYing a WatEr-
BaSEd Floor FiniSH
Stirred, nOT SHAkEn
Applying a water-based polyurethane does not
don’t shake clear floor finishes to mix them as
differ much from applying an oil-based finish
you do paint. shaking will entrap air bubbles
and, as noted in the preceding section, water-
and leave blemishes—popped bubbles—when
based finishes are more benign. Although
the finish dries. instead, stir finishes thoroughly
“Finishes, Cleaning Solvents, and Applicators” on
from the bottom of the can. don’t thin finishes.
p. 569 offers general guidance, always follow the
manufacturer’s instructions.
if stirring doesn’t dissolve the finish “skin”
or other solids, strain the finish through a
Cutting the edge is the first step when apply-
paint strainer.
ing any type of floor finish. Use a brush or paint
pad to apply a 6-in. swath of finish around the
Renovation 4th Edition Page 131