Step 1: Prep work - Start with clean joints
To paraphrase Rodney Dangerfield, grout gets no respect.
Grout can ruin an otherwise great tile job. And yet grout and
proper grouting technique are often treated as an afterthought,
like the final few half-hearted steps of a tired runner
stumbling over the finish line. Grout deserves better.
Your tile deserves better.
The keys to a professional-quality grout job aren't secrets
shrouded in mystery. On these pages, we'll show you some
tips and techniques that will help your next grout job
go more smoothly and give your tile a professional-grade
Start by vacuuming out all that remodeling dust, debris and
any chips of dried thin-set from grout joints (Photo 1). If there
are high spots where thin-set has
oozed out and dried, use a sturdy-edged
tool to scrape it out and then
vacuum again, including the tile surfaces.
The last thing you want is to
push all that muck back into the joint
as you are floating your grout in.
Tip: Tape Off the Tile Before Grouting
For easier cleanup, tape off painted walls to protect them from grout. Also tape off
trim or inset tiles that feature imprinted patterns with crevices (Photo 9).
Step 2: Mix the grout by hand
Pour some grout out of the bag into a
mixing bucket. Pour water in a little at
a time and start mixing by hand using
a margin trowel (See “A Tiler’s Best Friend” below). Tip the bucket
toward you and roll it in a “cement
mixer” style as you mix (Photo 3). Be
sure to scrape any dry, unmixed grout from the bottom of the
bucket with your margin trowel. Keep mixing until all the
powder has been absorbed and it has the consistency of
peanut butter. When you're getting close, dribble in water
from a sponge. It only takes a little too much to create soup.
And don't mix grout with a drill and mixing paddle. This
method churns the grout and introduces air into the mix.
That weakens the cured strength and causes a type of discoloration
called “shading.” Besides, we're trying to mix
grout here, not make soufflé.
Let the grout “slake”
When your grout has reached peanut butter status, stop! Go
and make a sandwich, take out the trash, whatever. Let the
grout slake (rest) for about 10 minutes. This allows the
chemicals in the grout to work their magic. Skipping this
step may result in weaker, crack-prone joints. After slaking,
the grout will feel a bit stiffer, but don't add more water.
Remix the grout by hand again to loosen it up.
A Tiler's Best Friend
Buy yourself a margin trowel for 10 bucks. You'll use it for
mixing grout and thin-set, scraping out joints, cleaning buckets
and tools, spreading mayonnaise, flipping pancakes....
Mix grout to peanut butter thickness
As Thick as What?
Step 3: Load the grout float
You're now ready to grout. Tip the bucket toward you (like
you did when mixing) and “drag” some grout with your float
up the side of the bucket toward you. This pulls a “working
batch” closer to you and makes it easier to scrape up a
decent amount of grout onto your float. Push the float tight
against the side of the bucket and scrape off a dollop of grout
(Photo 4). Any excess that falls off will
only fall into the bucket and not off
the edge and onto the floor.
Step 4: Load the joints
Always grout the walls first, and
after they're finished, the floor.
That’ll keep you from messing up a
finished floor. Apply the grout diagonally
across the tile joints to squish
the grout into the joints (Photo 5). Use
whichever side or corner of the float
is necessary to fully compress grout
into the entire joint. On vertical surfaces,
apply grout upward. That way
you won't drop so much on the floor.
Step 5: Clean off excess grout
After you've filled all the joints,
make your first “cleanup” passes
with the float. Your goal is merely to
get as much excess grout as possible
off the face of the tile. Hold the float
at a sharp angle to the tile and scrape
excess grout from the surface. Use a
serpentine motion to make it faster
and easier (Photo 6).
Step 6: Sponge the surface
Once the grout has started to harden
(20 to 30 minutes), begin sponging
(Photo 7). Don't use just any sponge,
especially one from the kitchen;
choose a “hydrophilic” (water-loving)
sponge. They're sold near the tile
supplies. Make sure it's damp, not
wet, and sweep diagonally across the
face of the tile and wipe the grout off
the tile surface. On your first few
passes, the grout will smear all over
the tile and look like a mess—that's
OK. Just rinse out your sponge often
in a bucket of clean water (never in
the sink) and keep wiping until most
of the smeared-on grout is gone.
Step 7: Tool the grout lines
When the surface has been cleaned, begin “tooling”
(smoothing and leveling) the grout lines with the sponge.
Hold the sponge in your palm and, gently pressing down
with your index finger, run the sponge over any grout joints
that look too high or uneven (Photo 8). The goal is consistent,
even-depth grout joints. Don't push too hard; let the sponge
do the work.
Step 8: Towel off the haze
After all the joints have been
dressed, step away for about a half
hour to let the surface dry and form a
haze. Then wipe away the haze with
a towel. Regular towels work, but
microfiber towels are the hot ticket
for this task. With more fibers, they
remove grout haze much quicker and
cleaner than a regular towel.
Store extra grout in a plastic bag.
Tip: Keep Some Grout for Repairs
It's a good idea to hold on to a small
quantity of unused grout for future
touch-ups. Grout will easily absorb
ambient moisture, so store it in an
airtight container such as a resealable
plastic bag or a canning jar.
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Step 9: Caulk all inside corners
Don't grout inside corners. Inside
corners that are grouted will always
crack over time. Choose a matching
color caulk designed to coordinate
with the grout you've used. It's sold
in matching colors near the grout.
Sanded vs Unsanded Grout
Sanded grout is stronger than unsanded grout and resists
shrinkage and cracking better. As a rule of thumb, sanded
grout should be used in joints larger than 1/8 in. Realistically,
as long as you can force the grout into the joint, use sanded
grout. But on soft stone tiles like polished limestone or marble,
use only unsanded grout or you'll scratch the surface.