Re-discover Terrazzo By Tony Torriano

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.