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STONE
RESTORATION
Q. What is the difference between marble
and granite?
A. Although both are stone and they're
quarried from the earth, granite and marble (marble's relatives
- limestone, onyx and travertine) are very different from each other.
Granite is formed deep in the earth's mantle at extremely high temperatures,
and is a very hard, resistant stone made of crystallized minerals.
The marble family: limestone, travertine, marble, onyx. It begins
as sediment; animal skeletons, shells, plant matter, and silt at
the bottom of bodies of water. After millions of years this solidifies
into stone.
Q. I have just purchased a house that
has a marble hall. The flooring is about 10 years old. I understand
that it should be sealed to reduce staining and dirt from penetrating
into the pores of the stone. What do I seal it with? It is also dull
and needs to be polished. How do I polish it and with what?
A. After 10 years of foot traffic a marble floor needs to be re-polished.
If the original installation is good, you can get away with a two
step restoration procedure; Honing and Polishing. If the original
installation is bad (excessive lippage), then the floor must go through
a three step restoration procedure; Grinding, Honing and Polishing.
You need special equipment that you won't be able to rent anywhere.
You need proper grinding and honing attachments. As well you need
a good quality polishing powder. Then most importantly, you need to
know what you're doing!
Hire a good, reputable stone restoration company to refinish your
marble floors (Do NOT, shop on price! Ultimately you will get what
you have paid for). Then learn how to properly take care of them.
How
to hire? (pdf. file)
Q. What is the best way to clean marble
and other stones?
A. The old rule of thumb is never to
use anything you wouldn't use on your hands. Never use powdered
cleansers or abrasive pads to clean your stone. Even "soft
scrub" type cleaners contain pumice (powdered volcanic stone),
which could damage your stone countertops or floors. Never use any
products which are acidic or alkali; this includes substances like
ammonia or many common liquid cleaners such as Fantastic, Windex™.
Q. I have travertine coffee and dining
tables. They have become scratched and have some stains in them. Can
I use vinegar to clean them?
A. Travertine is a calcareous stone
and sensitive to acidic cleaning. Be cautious. Vinegar and other
acids will etch the finish of the stone and take the polish off.
Q. We have a commercial property which
was recently renovated. We are not happy about how our floor is leveled.
Is there any "tolerance for lippage" as a standard?
A. Lippage is a condition where edges
of the tile are not at the same plane with each other. What are
acceptable industry standards? This has resulted in many conflicts,
because what may have been acceptable to the installer was not acceptable
to the owner, resulting in litigation or withholding payment to
the subcontractor.
Lippage should not exceed 1 mm when setting square edge tile with
narrow joints (3 mm or less). More lippage can be tolerated when
wider grout joints are used or when the tile doesn't have a square
edge. Lippage should not exceed 1 mm per 3 mm joint width. (TTMAC
2000 Specification Guide 09300 Tile Installation Manual Notes on
Page 10)
Q. We inherited a marble coffee table.
The marble had at one time been given a coat of clear varnish that
had yellowed over time. So we sanded off the varnish and now the marble
is white and beautiful, but dull. Since we want to use this as a coffee
table that people would be setting their glasses on; how do we: 1)
Make the marble top shiny? 2) Protect the marble from glass rings?
We already tried a spray marble polisher, and it didn't do anything...
A. There are no ways around it; you
need to hire a professional. There is nothing you can apply onto/into
it to protect it from "glass rings". Use a coaster all
the time. We once suggested a customer to have a piece of glass
custom-cut to put on top of the marble. To minimize detrimental
effect of staining seal you stone with
impregnator (pdf.
file)
Q. I would like to know how to hone an
existing marble floor that is 75 yrs old but in good condition. It
never had a polished finish. There are many light scratches and worn
areas that we would like to remove. If I hire a craftsman, what should
I be aware of about their work and how do I judge an acceptable job?
A. We would recommend hiring a professional
marble restoration company. If it does the job properly, you will
know!
STONE
PROTECTION
Q. Many marble installers talk about
sealers. What actually is the "sealing"?
A. Sealers in the stone industry are
called
impregnators (pdf. file)
because they impregnate the interior of the stone with silicones
and resins that go through the pores of the surface. Stone sealers
do to stone what exterior wood sealers do to wood. They protect
the interior of the material.
Q. We had a new green marble vanity installed
in a washroom. Why should we seal it?
A. To save your money. The main objective
of the impregnator is to protect the interior of the stone from
staining. They help prevent fluids from penetrating through the
pores. Sealing is a preventive measure that provides extra protection
to the stone. The vanity should be sealed with quality impregnator
ASAP.
Q. Do stone impregnators really protect
the surface?
A. Technically, to a limited extent.
Impregnators will not prevent traffic patterns or scratches, nor
will they prevent etching from acid spills on marble. An impregnator
will keep the acid out of the stone but not off the top surface.
Q. Our
property management looks after a downtown Ottawa building which
has a White Carrara marble lobby. Can we be sure that applying marble
sealers to our stone is protecting it against wear?
A. Unfortunately, no. Penetrating sealer
has nothing to do with mechanical damage of the surface.
Q. Impregnators will not prevent wear,
scratches and etching. Should my stone still to be sealed? Would my
installers have done it already?
A. All stones need to be sealed with
a penetrating sealer. Most contaminants that damage your stone are
water or oil soluble. Premium silicon impregnators that reject both
water and oil should be used. By applying this type of sealer, you
will have more time to blot up spills before they penetrate your
stone's surface. Never assume your contractor or installer has sealed
your stone. Always ask if it has been sealed and with what type
of sealer.
Q. A marble
company just installed limestone tiles in our kitchen and sealed
it. Does sealed limestone need to be maintained?
A. Yes. It is just like taking care
of the paint on your car. If you wax or seal the paint, you still
have to wash it regularly. Sealers will last longer when the stone
is properly cared for.
Q. We have
heard different stories about impregnators. Some people say, they
last forever, others say for one season. How often should the sealers
be reapplied?
A. Most domestic applications should
be done annually, because they do not last forever. Over time the
sealer loses its strength and bonding to the stone. Just like the
penetrating exterior wood sealer, it eventually breaks down and
must be reapplied.
However this will be accelerated in certain conditions. For example,
in a high traffic area, the impregnator wears as the stone surface
wears down. The sealer only penetrates to a maximum of about 1.5mm.
As stone porosity varies significantly the sealer penetration will
also vary significantly.
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