Introducing our floor-sanding expert
Sanding hardwood floors might seem like a pros-only
project. It’s a big job that creates big disruptions in
your household. And then there’s that big, scary
But it’s really not that difficult. I’ve helped hundreds
of homeowners—some of them complete DIY novices—successfully prep their floors for a new
finish. Here are some of my most important tips for
So says our expert, Kadee Macey, owner of Pete’s
Hardwood Floors in St. Paul, MN.
Despite a background in art history
and English literature, she’s
spent 13 years sanding hardwood
and teaching others to do it
themselves. And competing in roller derby in her spare time.
Good-bye base shoe
If a room has quarter-round molding
(aka “base shoe”) at the bottom of
baseboards, I usually pry it off and
reinstall it later. Here’s why: Edge
sanding slightly lowers the floor and
leaves the baseboard standing on
a little plateau. You think you won’t
notice this, but you will. Edge sanding
also scuffs up base shoe, which
means touch-up work later.
Removing the base shoe sidesteps
both problems. Label the
base shoe as you remove it to
avoid confusion when you reinstall
it. Exception: If the base shoe is
bonded to the baseboard by
decades of paint buildup, I leave it
in place. If you have newer baseboards
and no quarter-round, leave
it in place, but expect lots of the
Pet stains are forever
Water stains usually disappear
after a couple of passes of the
sander. But stains caused by pet
urine often penetrate so deep into
the wood that you just can’t sand
them out. Bleach formulated for
wood floors may be worth a try,
but in my experience the results
are mediocre at best, and at
worst, the wood is left pitted
Often, the only solution is to
replace the wood—or finish over
the stain and think of it as a permanent
memorial to a beloved pet.
How do you tell water from pee?
Pet stains are darker (deep gray,
almost black around the edges)
and often look like a map of
Indonesia, with big and small
islands covering a large area. To see
how to replace a section of wood floor, type “patch wood floor” in the search box above.
Prep the room
Some of the prep work is obvious, like removing all the
furniture and covering doorways with plastic. Here are some
steps DIYers often don’t think of:
- Cover or plug air grilles to keep dust out of ducts. Turn off
the HVAC system at the thermostat; less air movement
means less dust traveling around your house.
- Remove all window coverings and any art on the walls
(unless you want to clean them later).
- Remove doors that open into the room. You can’t
completely sand under doors, even by opening and
- Raise low-hanging light fixtures; just tie two links of the
chain together with wire. Otherwise, you’re guaranteed to
bump your head. Repeatedly.
- Nail down any loose boards
with finish nails.
- When you’re sanding, nail
heads will rip the sanding
belt (which costs you money)
or gouge the sanding drum
(which costs you more
money). So countersink all
nails by at least 1/8 in.
- To detect nails
drag a metal snow
shovel across the
floor (upside down).
When it hits a nail,
you’ll hear it.
You’ll need two rental
machines: a drum sander to
sand most of the floor and an
edger to sand along baseboards.
Here are some tips:
- Rent from a flooring specialty
shop rather than a general
rental store. You’ll get expertise
at no extra expense.
- Measure the room. Knowing
the square footage will help
the crew at the rental store
estimate how many sanding
belts and discs you’ll need.
- Prep before you rent. The
prep work will take longer
than you think. Don’t waste
money by picking up the
sanders before you’re ready
to use them.
- Get a drum sander that uses
a continuous belt or sleeve,
not one that requires you to
wrap a strip of abrasive
around the drum. That’s
tedious and often leads to
chatter marks on the floor.
- Think twice before you rent a
flat-pad sander (aka “orbital”
or “square-buff” sander).
Sure, they’re easier to use,
but they’re just not aggressive
enough to bite into
finishes or hardwoods.
“We don’t rent flat-pad sanders. For most jobs they just don’t work.”
- Choose a sander that has a
lever to raise and lower the
sanding drum. That makes
graceful stops and starts easier—and reduces gouging.
Scrape out corners
When the sanding is done, use a paint scraper to attack
spots that the machines can’t reach. A sharp scraper
will leave a super-smooth glazed surface that won’t take
finish the same as the surrounding wood. So rough up
scraped areas with 80- or 100-grit paper.
Pick a starting grit
It takes coarse abrasive to cut through a finish and into
hardwood. But determining just how coarse isn’t easy for
a DIYer. So I recommend a trial-and-error process: Start
with 36-grit. If that doesn’t completely remove the finish
in one pass, step down to 24-grit. If 24-grit doesn’t
remove at least three-quarters of the finish in one pass,
go to 16-grit. Regardless of which grit you start with, all
the finish must be gone by the time you’re done using
Nix the stripper
DIYers often think that
paint stripper is a good
way to get rid of the
finish before sanding.
But don’t waste your
time. Sanding is faster.
Change belts often
I sell sanding belts, so this might sound
self-serving. But trust me. Using dull
belts is a strategy you’ll regret. Here’s
the problem: After the floor finish is gone,
you can’t see whether the sander is doing
its job. So you keep sanding. The machine
is raising dust and everything seems fine.
But the dull paper isn’t cutting deep
enough to remove the scratches left by
the previous grit. And you may not
discover this until you put a finish on the
floor. A dull edging disc is even worse,
since it won’t remove the ugly cross-grain
scratches left by the previous disc.
Even if paper feels sharp, it may be
beyond its prime. So the best way to judge
is by square footage covered. The belts
I sell cover about 250 sq. ft., and edger
discs are spent after about 20 sq. ft. That varies, so ask at the rental store.
The edger is basically a sanding disc
mounted on a big, powerful motor.
A simple tool, but not so simple to use.
Here are some tips to help you master
the edger and minimize the inevitable
swirls left by the spinning disc:
- Follow up each phase of drum sanding
with edging. After you’ve drum-sanded
at 36-grit, for example, edge with
- Place a nylon pad under the sandpaper.
This cushion minimizes gouges
and deep swirls. Get pads at the rental
- Replace the sandpaper when it’s dull.
Dull paper won’t remove swirls left by
the previous grit.
- At the end of the job, lay a flashlight
on the floor to highlight any leftover
swirls. Then hand-sand them out with
80- or 100-grit paper.
- A warning to woodworkers: You’ll be
tempted to edge with your belt sander,
but even the biggest belt sander can’t
cut half as fast as an edger. You’ll also
be tempted to polish out swirls with a
random orbit sander. But beware: That
can overpolish the wood so it won’t take
finish the same as the surrounding
wood. Hand-sanding is safer.
“Edging with a belt
sander is like digging
a ditch with
a trowel. You can
do it, but it will
Don't skip grits
The initial coarse grits remove the finish and flatten the wood. But that’s not
enough. You need to progress through every grit to polish off the scratches left
by the previous grit. On most of my jobs, the sequence is 24-36-60-80 for
coarse-grained wood like oak. Scratches are more visible on fine-grained
wood like birch or maple, so I go to 100-grit.
“The most common DIY
mistake is timid sanding.
If you don’t sand deep
enough, you’ll end up with
a dingy floor.”
Clean up between grits
Sweep or vacuum the floor before you move up to the next grit. Even the best abrasives
throw off a few granules while sanding. And a 36-grit granule caught under a
60-grit belt will leave an ugly gash in the floor. Wrap the vacuum nozzle with tape
to avoid marring the floor.
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Screen the floor
After you’ve finished with the sanders, the floor will look
so good that you’ll be tempted to skip this step. But don’t.
“Screening” blends the edge-sanded perimeter with the
drum-sanded field and polishes away sanding scratches.
You can do it with a rented buffing machine or with a
sanding pole (like the one used for sanding drywall).
Either way, the abrasive to use is 120- or 150-grit sanding
screen (again, just like the stuff used on drywall).
Note: For more of Kadee’s wood floor wisdom, go to
Does DIY make sense?
DIY floor refinishing typically costs about $1 per sq. ft. Hiring a pro costs from $3 to $4 per sq. ft. On average, especially on jobs that are larger than 500 sq. ft., my DIY customers save $1,000 by doing it themselves. Not bad for a weekend of work. Keep in mind that pro costs vary a lot, so it’s worth making a few calls to check on pro rates in your area.