Grout/Problems
and Solutions
There are basically two types of grout used that
are widely used today. They are referred to as Sanded and Unsanded.
Sanded grout consists
of: 1 part portland cement, 2 parts fine sand, cellulose (to
hold the water in the mix), defoamers (to prevent air entrapment
during mixing), and polymers (for strength and flexibility).
Unsanded grout consists
of: 1 part portland cement, 2 parts calcium carbonate (used
as a filler powder), cellulose, defoamers, and polymers.
Sanded grout
should be used when the spacing between tiles is 1/8" or
more. It tends to be more durable because of the silica sand
that it contains. Most floor jobs
will require sanded grout.
Unsanded grout
should be used when the spacing between tiles is 1/16" or
less. Because of the lack of the silica sand in unsanded
grout, it will penetrate the void much better. Most wall tile
will be spaced at 1/16" or less..and some wall tiles will
have self-spacing edges on them.
Granites, marbles,
and other natural stones will require unsanded grout for all
practical purposes. Granite tiles with chamfered edges are
usually set at very close tolerances to produce a very elegant
look. This requires the smooth unsanded grout to fill the void
because the sand particles in sanded grout will not penetrate
through.
Marble tiles share
some of the same characteristics of granite tiles but are much
softer. For this reason alone it is much safer to use unsanded
grout so as not to scratch the marble with the sand particles
present in the sanded grout.
I hear horror stories from many
people all the time when it comes to grout. People even give
up on the idea of installing a tile floor because of what happened
to them in the past.
Some of the problems I have heard
and experienced actually can be explained very easily. When
properly used, grout can be a long-lasting surface just like
the tile.
I will try to clear up some of the
mystery with a few basic principles:
Mix: Mixing instructions
are given on the bag or the box..READ THEM!
Whether you are using water or an
additive make sure you do not overmix the grout.. i.e. a power
mixer. This can trap air bubbles in the grout causing preamature
failure.
Do not add excessive water in the
mixture. This will weaken the grout and make it much more porous.
The grout will lack durability and will stain more rapidly.
Grout should have a consistency of mayonnaise or toothpaste
when mixed.
Let it "slake"...
This term refers
to letting the grout sit in the bucket for at least 10 minutes
after mixing. This helps the chemicals interact with one
another before use. After the "slake" period remix slightly
then apply.
Floating: Buy a good
grout float. Avoid the economy floats with the patterned grooved
faces on them. These floats leave lines in the finished grout
joint and should be avoided.
A good pro float with a totally
smooth face on it usually only costs a few dollars more and
is well worth it.
Work the grout into the voids at
a 30 degree angle. This prevents removing excessive grout from
the joints.
Be very systematic in your application
of the grout. I usually divide my job up in quadrants and apply
the grout as such. This permits me to deal with any problems
that surface along the way and also keeps me from letting the
grout dry too hard.
Clean-up: Avoid over
washing the grout. This will wash away the surface pigments
and also produce lower joints that can vary in color.
Do not continue to wipe and clean
the grout after it has begun to set. This will remove the smooth
cement surface paste exposing the sand or aggregate. A rough,
gritty appearance will result.
Rinse your grout sponge often. This
will prevent build up on the tile that will be hard to clean
later. Also the paste deposit on a dirty sponge will collect
in the voids of the grout joints leaving a rough residue that
will make the joints vary in color.
Sealing: There is disagreement
among many installers, manufacturers, and homeowners when it
comes to sealing grout.
Basically sealing is just like everything
else. When done properly it can be very beneficial.
There are many good sealers available
today. One I particularly like is HMK S-34.
This is an excellent penetrating silicone sealer and impregnator
(also used for stone sealing).
Whatever sealer you choose the main
thing to remember is make sure the grout has fully
cured before you apply the sealer. If the grout hasn't
had time to dry thoroughly you will trap the moisture in the
joints and the silicone sealer will just sit on the surface
instead of penetrating through the grout joint. This will make
the grout stain and it will become hard to clean. I usually
recommend waiting a week after installation before the grout
joints are sealed. This will give adequate time for a full
cure before sealing.
Tip: If your job is
located in an area where grout will dry too fast such as by
heat vents, direct sunlight, or by porous wood bases make sure
the grout is kept moist. This can be accomplished by misting
the grout periodically or by placing craft paper over the area.
If the grout drys too fast most
assuredly there will be dark patches throughout your area.
Hope this information helps you
with your job. |
