Stone
Maintenance Guide
Marble
- Limestone - Granite
- Slate
This report
is a short summary and general guide of maintenance recommendations
and processes which have proved practical for many stone surfaces
over the years. It should not be assumed that any particular process
description or recommendation is suitable for any particular project
or situation without qualification. There are many variables which
must be considered when designing a maintenance program including:
physical properties of the stone, abrasion risk, hostile factors
in the environment, the maintenance budget and the skill of the
maintenance personnel. It is highly recommended that a maintenance
professional be consulted if there is any doubt about whether
or not a specific method or product is safe and effective.
Marble
Composition: Calcite, Calcium Carbonate
Hardness: Soft
Absorption: Oil, Water
Limitations: Absorbs oils and other liquids, easily scratched,
acid sensitive
Sealer: Penetrating type siloxane or fluoropolymer
Cleaner: Natural Soap or Neutral pH detergent
Finish: Polished - liquid Paste wax ; others: none
Notes: Polished marble is ideal for vertical application but requires
a high level of maintenance when used as flooring especially in
high traffic situations. Non-reflective finishes perform well
as flooring with minimal maintenance once treated with recommended
sealers. Kitchen use should be carefully evaluated due to oil
absorption.
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Limestone
Composition: Calcite, Calcium Carbonate
Hardness : Soft
Absorption : Oil, Water
Limitations : Absorbs oils and other liquids, easily scratched,
acid sensitive, polished-interior use only
Sealer : Penetrating type siloxane/fluoropolymer
Cleaner: Natural Soap or Neutral pH detergent
Finish: Polished - liquid Paste wax ; others: none
Notes: Most true limestone types are porous and absorbent. Some
limestone is semi-metamorphic and will have physical properties
similar to metamorphic marble. If the limestone is metamorphic
it is "Marble". For our purposes here, LIMESTONE is the chalky
porous type typical of most French and Spanish limestone. Non-reflective
finishes are practical as flooring but require sealing to minimize
stains. Dense, low absorbent varieties of limestone can be suitable
in shower areas but beware of using too soft a limestone in high
stress areas. Sealing is normally recommended for both interior
and exterior locations.
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Granite
Composition: Quartz, Feldspar (varies)
Hardness : Hard
Absorption : Varies - Oil, Water
Limitations : Absorbs oils and other liquids, brittle
Sealer : Sub-surface repellents - oil repellent type recommended
Cleaner: Neutral pH detergent or pure soap
Finish: None Normally - Wax OK
Notes: Granite is typical for kitchen counter use. Sealing is
recommended for most stones. Granite is the hardest of the polished
stones commercially available and is used in high stress situations.
Polished granite usually is more absorbent to liquids than many
people suppose. Flamed granite surfaces are very absorbent due
to the stress fractures in the stone caused by the flaming process
and should be sealed if it is desired to maintain the original
color and appearance of the stone over time.
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Slate
Composition: Muscovite Chlorite (wide variation in composition)
Hardness : Soft - easily scratched
Absorption : Low - medium oil, water other liquids
Limitations : Absorbs oils/ liquids, cleft planes can spall
Sealer : Sub-surface repellents oil repellent type recommended
Cleaner: Neutral pH detergent or pure soap
Finish: Acrylic OK - wax OK
Notes: Cleft slate is very durable in most situations but quality
varies. Slate is typically rustic in appearance but some milled
or smooth products are available in some varieties. Wear is typically
taken on the peaks or high spots of the textured surface. Acrylics
are used when a highly reflective finish is desired. Excellent
exterior paving stone. Higher absorbency varieties may not be
suitable for exterior areas in freezing climates.
Slate characteristics vary with source. Domestic is typically
black, green or mottled (Pennsylvania) and is relatively dense.
Many imported slates are available today with wide ranging physical
characteristics and overall suitability. Evaluate your stone for
density, tensile strength, absorbency and abrasion resistance.
Make sure your slate characteristics are compatible with the intended
function.
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