Cleaning Fresh Grout
Cleaning grout off the tile will be easier if you remove the
excess with the edge of the grout trowel during application, as
mentioned earlier. Once all the joints are filled, you’ll
need a round-edged sponge, buckets of clean water, plenty of
elbow grease, and lots of patience and attention to detail.
Timing is just as important as technique and using the right
tools. Wash the grout too soon and the sponge will remove too
much grout material from the joints; wait too long and the
sponge will gouge out grout as you attempt to smooth the grout
crust capping each joint. Test the grout to see how easily it
can be cleaned — this will spare you the pain of
spreading more grout than can be properly cleaned.
One secret to successful grout cleanup is to use the
absolute minimum amount of water to get the job done. Begin
cleaning by dipping a round-edged sponge in clean water, then
wringing it out thoroughly. Be careful to avoid splashing the
grout lines — water droplets can alter the hue of colored
grout and can weaken any Portland cement grout.
With a light circular motion, scrub away any grout residue
crusted on the surface of the tiles (Figure 8).
8. Begin cleaning by wiping the tile with a
clean, damp sponge, using a light circular motion, then
make a final pass with the sponge using long, straight
strokes (top). After the tile dries, remove any grout
haze from the surface with a soft cloth or towel
Rinse the sponge before its pores become too clogged with
grout particles, wringing as much grout from the sponge as
possible, and shaking excess moisture back into the wash
bucket. Work a 10-square-foot area at a time, repeatedly wiping
and wringing until all grout and sand particles are
Next, rinse the sponge thoroughly and start cleaning the
grout in the joints. The goal here is to "unify" the grout by
shaping all joints to the same profile and width. The final
shape of the grout lines depends on the shape of the edges of
the tiles. Grout joints between tiles with a crisp, tight edge
will be high and preferably on the flat side; grout joints
between round-edged tiles will sit lower. All voids and gaps
should have been filled while troweling the grout, but any that
you find during cleaning should be packed with fresh grout.
Work as delicately as you can with the grout trowel to keep
from smearing grout over tiles you just finished cleaning, but
be sure to pack the grout firmly into the gaps and voids.
It’s easier to clean the tiles a second time than to come
back later to replace a failed joint.
When the joints are uniform and the tile surface is cleaned
of visible residue, the tile is ready for one last wet
cleaning. With a damp sponge, make long, straight passes, using
a clean face of the sponge for each pass. Use gentle pressure
on the sponge and keep it moving slow and straight. When one
10-square-foot area is complete, move on to the next area, and
repeat the whole process until all of the tile is clean.
The haze that appears after the tile dries can be removed
quickly with a soft cloth or towel. As the grout begins to firm
up, you can clean the expansion joints of any excess grout as
After the tile is clean, strike the joint with a nail set or
old drill bit to fully consolidate the joint (Figure 9).
9. Sanded-grout joints on floors or countertops will be
easier to keep clean if you push the sand particles below the
surface by striking the joint with a nail set or dull drill
This is especially important with sanded grout in wet areas,
such as kitchen countertops, because it pushes the sand down,
making the joints easier to keep clean.
Clean latex grout the same way. Timing is important because
it’s a little more difficult to remove latex grout if it
sets up too long, but inexperienced installers typically make
the opposite mistake and begin cleaning too soon. Judgment
improves with experience, and it may make sense to grout and
clean a small test area to get a feel for it.
Irregular or porous tiles, such as Mexican pavers or
hand-molded tiles with lots of pits in the surface, can be
sealed at the factory with a grout release compound like
paraffin to make cleaning easier. This is rarely done in
residential installations, however, because the wax can only be
removed by steam cleaning.
To achieve the
expected level of performance, all Portland cement products
(concrete, setting bed mortar, adhesive mortar, and grout) must
be properly cured. Damp-curing — which simply requires
some means of keeping the grout wet as it hardens —
ensures that enough moisture is available for the chemical
process that turns the dry powder into hard stone. Cut off the
supply of water and the hardening process stops.
The simplest way to damp-cure is to lay Kraft paper over all
of the grouted tile to keep the moisture from evaporating too
rapidly. Don’t use poly, which will trap condensation on
the surface of the tile. This will not aid hydration, but could
discolor the grout.
Leave the paper in place for at least a day, then remove it
and mist the tile or wipe it lightly with a damp sponge.
Depending on room temperature and humidity, you may need to
repeat this process for several days to achieve a full cure.
Damp-curing is rarely needed with latex grouts, but may be
required in hot, arid climates.
Narrow, shallow joints require less curing time than wider,
deeper joints. In moderate climates, allow approximately 7 to
14 days for complete hydration. Using latex in Portland cement
grout reduces the amount of labor required for damp curing
because the latex encapsulates the moisture needed to complete
hydration. The money saved on labor more than offsets the added
material cost of using latex, although some damp curing may be
required where ambient room temperatures are unusually
The choice of which grout to use for a particular
application depends on the width and location of the joints
(floor, wall, or countertop), whether or not the tile is
located in a wet area, and the amount and type of use the tile
Sanded or Unsanded?
type of tile and the width of the joints between tiles
determines whether to use sanded or unsanded grout. For joints
up to 1/8 inch wide, unsanded grout is the best choice,
especially if the tile has a soft glaze that can be easily
scratched. As the joint dimension widens to between 1/8 and 1/2
inch, using ceramic-grade sanded grout strengthens the joint in
much the same way as aggregate strengthens concrete. Sand also
helps reduce the number of shrinkage cracks in the grout.
For joints wider than 1/2 inch, grout made with coarser sand
than that found in the ceramic grade is also available.
Although not made by all manufacturers, this grout is often
specified for hand-molded tiles like Mexican pavers which,
because of their irregular dimensions, require wide joints.
For dry light-duty interior applications (such as purely
decorative wall tile), regular sanded or unsanded Portland
cement grout will do and can be prepared simply by adding clean
water to the grout powder.
For high-traffic or
wet areas, latex grout makes for a more durable installation.
Latex grouts are available in three basic forms. The first is
made by adding liquid latex to regular sanded or unsanded
grout. A second type, called polymer-modified grout, is
manufactured with latex in dry form, and requires only the
addition of water. A third type, called fortified
polymer-modified grout, is manufactured with dry latex and is
also mixed with a liquid latex. Because the chemical formulas
vary from manufacturer to manufacturer, these high-performance
latex grouts should always be prepared according to each
manufacturer’s written instructions.
The same is true for
epoxy grouts, which come in two types. Epoxy emulsion grouts
are made by site-mixing a powder base of Portland cement and
sand with an epoxy resin and a hardener. The resulting mix
offers moderate resistance to certain chemicals (as specified
by the individual manufacturers) and can be applied and cleaned
off like regular or latex grouts.
The other type of epoxy grout is called 100% solids epoxy
grout, because there is no Portland cement in the mix —
only silica sand, epoxy resin, and an epoxy hardener or
catalyst. Application techniques for 100% solids epoxy grout
are substantially different from Portland cement varieties.
Depending on the manufacturer, 100% solids epoxy grout is
available as a three- or two-component kit. Three-component
types are composed of a resin, a catalyst, and silica sand.
With two-part grout, the sand is premixed with one of the epoxy
components, eliminating dust during site mixing. Again, follow
the manufacturer’s selection, mixing, and application
instructions for best results.
Handling and Storage
grout components are usually sold in kit form and are tightly
sealed in a covered plastic pail that doubles as the mixing
container. These kits should be stored away from sunlight and
extremes of heat or cold.
The same applies to Portland cement grouts. Because the
powdered components are shipped in paper sacks, they must also
be protected from water, which can wreck dry grout by turning
the powder into useless, hardened lumps. Even high levels of
humidity, given enough time, can affect grout powder at the
particle level. This may have no effect on grout that is mixed
and applied immediately after exposure, but if the powder
remains in storage, the resulting mixed grout will not perform
as well, since the grout particles have been hydrated by the
humidity. Hydrated grout mixes, spreads, sets up, and behaves
like fresh grout, but when it cures, it has no strength and
often turns back into powder. If you leave leftover grout
powder with the building owner for future repairs, it should be
stored in a sealed glass or plastic container.
Michael Byrne has worked extensively with tile for more
than 30 years as an installer, contractor, and author. He
provides consulting services from Los Olivos, Calif.