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Re-discover
Terrazzo
By Tony Torriano
Several hundred years ago in Venice, Italy a flooring system was
created that has withstood the test of time and is still in use today.
Terrazzo, from the Italian word terrace, was discovered by Venetian
workers who found another use for discarded marble remnants created
from odd size pieces of custom marble fabrications. It was recognized
as a craft in 1579 by the Supreme Institution of the Venetian
Republic. Prior to that time it was considered art and people
practicing this were part of a minor branch of the art of the "mureri".
In that year the "Mariegola dei Terrazeri" was drawn up that
contained a list of apprentices or persons qualified for the
construction of terrazzo floors. As a form of art, terrazzo was used
in stately buildings from numerous palaces across Europe for Kings and
Princesses to the Vatican and during the late 1700’s the craft was
brought to North America by skilled European immigrants.
Technological advancements in both installation techniques and range
of available aggregates have impacted terrazzo, but the beauty,
elegance and durability still exists today. From these roots of
antiquity, today terrazzo is considered a contemporary flooring choice
for use in buildings of our time. Over the past few years the
appearance of terrazzo has been updated with new colors, natural
aggregate, glass aggregate and the addition of metal particles or
components. Combined with the improvements in the installation process
and new equipment for grinding, terrazzo has experienced a revival as
a choice floor system for heavy commercial areas or to create special
effects in almost any application.
Terrazzo types
Although terrazzo offers the same general appearance the
system may in fact be different beyond what you can see. There are
several types of terrazzo systems that are first categorized by the
binder type or paste that holds aggregates together like cement,
acrylic (polyacrylate) or epoxy. Within the cement category, there are
varying systems that have different overall thickness ranging from 13
mm to 75 mm (1/2" to 3") and are defined by the under bed
layer. Each system offers benefits and functions that may be required
for different construction methods. These systems include: Floating,
Bonded, Epoxy bonded, Semi-Venetian, Venetian and Rustic.
During the 1960's the introduction of epoxy and acrylic binder
compounds led to the development of thin-set terrazzo with thicknesses
ranging from 6 mm to 10 mm (1/4" to 3/8"). These systems are
lightweight, easier and faster to install and because of their thin
profile they are ideally suited for renovation or rehabilitation work.
For new construction, other finishes such as tile or carpet can easily
be placed adjacent without the need to depress the concrete base slab.
Advancements in polymer resin technology resulted in these systems
being solvent free with virtually no odor, therefore, much more user
friendly than the original. Over the last 7 years these systems have
seen a significant increase in usage in Canada and throughout the
United States.
Colors and aggregates
The binder that holds all aggregate particles together can be
pigmented to almost any color and with the ever increasing use of
epoxy as the binder, the spectrum of color and accuracy is unlimited.
Natures' pallet of color is available from marble aggregates that are
sourced within North America or Europe. Other aggregates like granite
or washed, screened and graded stones can also be incorporated into
terrazzo. Colored or recycled glass can be added to terrazzo in
varying proportions or can be used exclusively. The use of glass
allows the designer to incorporate unique or bold colors that are not
available with marble aggregate colors for accents or special effects.
Crushed sheet mirror or manufactured mirror particles that are
available in different colors may be used to create sparkle or depth
to terrazzo. Metal shapes, letters, or filings can also be
incorporated into terrazzo for additional effects. The combination of
new and recycled materials allows for virtually any design, pattern or
image that is limited only by the imagination.
Advancements
Terrazzo has undergone many changes since its discovery, from
installation techniques, to types of strips used. Divider strips
originally consisted of wood that was used for shrinkage control that
were later removed and filled with a mortar and finer marble chips.
This method was later replaced with the placement of 19mm(3/4") x
19mm(3/4") marble strips that remained in the terrazzo surface.
During the 1920's metal divider strips became available and continue
to be used today with many different types of thickness and metal
choices like zinc, aluminum or brass. Plastic strips were introduced
through the mid seventies and offer a choice of color to complement
the overall design.
By far one of the greatest improvements has occurred in the grinding
procedure. From a manual process using a wooden pole with an abrasive
stone attached to one end, referred to as a "Galera" this
process was mechanized during 1924 to included rotary abrasive stones
and plenty of water. Within the last five years this process has been
significantly improved with the use of diamond abrasive stones in a
dry process. This advancement has had considerable impact because it
has greatly reduced the time required for grinding. Furthermore, the
"pacerina" or residual slop has been eliminated and dust
particles generated from grinding are captured with high powered
vacuum units with efficient filters. Although wet grinding may still
be necessary for polishing, the time saving and residual slop has been
dramatically reduced.
The floating terrazzo system that ranges up to 75 mm (3") is
designed to prevent or suppress the transmission of cracks that may
form in the concrete base slab. This crack suppression concept has
been adopted by thin-set epoxy type systems and has recently led to
the development of anti-fracture membranes. These liquid applied
membranes suppress the transmission of cracks that may occur in
concrete and are directly bonded to the concrete base slab prior to
the installation of an epoxy terrazzo system.
Maintenance and Life Cycle
Terrazzo has always been valued for its durability and subtle
beauty. From its ancient beginnings, terrazzo has been used for floors
in commercial buildings, hospitals, offices, churches, and airports
and was considered the flooring material of choice in the commercial
buildings industry of the 1950's and early 1960's. Independent studies
have shown that when initial cost, replacement and maintenance costs
are considered over a period of ten years the cost of terrazzo is less
than most other floor finishes. When the same criteria is looked at
over a 40 year period, the cost of terrazzo is significantly less than
most other floor finishes.
Terrazzo, the floor that was invented centuries ago and walked upon by
everyone has been updated in appearance and new technologies have been
applied to it, so that it is faster and easier to install and appeal
to current design trends. It is being used on many projects from small
areas to create special effects to large mega projects like the new
Terminal Building at Pearson International Airport. With the recent
developments, color options and aggregate choices, there are more
applications available for terrazzo than ever before.
Tony Torriano is National Sales Manager for Duochem
Inc. and has over 14 years experience in polymer flooring, wall
coating and parking garage waterproofing systems. He graduated from
York University with a Bachelor's Degree in Chemistry. Tony is
actively involved with various industry associations and is the Past
Chairman for the Toronto Chapter of Construction Specifications Canada
and presently a Director of the Terrazzo, Tile and Marble Association
of Canada.
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