Clicking the link below will Exit the WSTA website to go to our parent organization's website:
https://www.ntma.com
Terrazzo Systems
- Epoxy / Resin Terrazzo
- Sand Cushion Portland Cement Terrazzo
- Bonded Portland Cement Terrazzo
- Rustic / Washed Portland Cement Terrazzo
- Polyacrylate Modified Cement Terrazzo
Considerations for Terrazzo System Selection
- Does the terrazzo system need to be breathable if installation is slab on grade over an existing concrete slab which may not have an effective moisture vapor barrier?
- Is there a terrazzo system thickness constraint, as systems range from 3/8" to 2 1/2" and typically require a depressed subfloor for systems greater than 1/2"?
- If terrazzo is being proposed for an upper level of a structure, is there a weight restriction?
- The proposed matrix colors may be a factor in selecting a terrazzo system.
- Use of glass, plastic, or metal aggregate will be a factor in selecting a terrazzo system.
- Metal divider strip design and terrazzo panel sizes may determine which terrazzo system to use.
- Time constraints for installation of terrazzo system may be a factor in system selection.
- Washing terrazzo for non-slip finish is a factor in terrazzo system selection.
Terrazzo Matrix Colors
Terrazzo's matrix binder allows virtually any color of Terrazzo to be
produced. While there is a wide but limited range of marble and glass colors, virtually
any color can be produced with Epoxy Resin Terrazzo. And a wide range of colors
can be produced with Portland Cement and Polyacrylate Matrixes.
Terrazzo Aggregates
Excellent quality domestic and imported marble chips are available for Terrazzo in a
wide range of colors, which can be combined to create an infinite variety of color complimenting
the marble chip colors. And there are is a wide variety of colored glass chips available to create colors in which
marble is not available.
Though glass chips may be used in Epoxy Resin and Polyacrylate systems, it is not recommended in cement matrix systems. Metal chips and shell are also commonly used in Thin-set Epoxy Matrix Terrazzo.
Though glass chips may be used in Epoxy Resin and Polyacrylate systems, it is not recommended in cement matrix systems. Metal chips and shell are also commonly used in Thin-set Epoxy Matrix Terrazzo.
Terrazzo Marble Chip Size
Terrazzo marble/glass chips vary in size from approximately 1/16" in diameter to 1" in diameter.
There is a number designation used with #00 being the smallest chips up to #7 being the largest chips.
Use of the largest chip sizes is commonly referred to as Venetian Terrazzo.
As with colors, marble chip sizes can be combined to create variations in the appearance of the Terrazzo. Terrazzo chip sizes have limitations based on the type of Terrazzo systems being used. (See Allowances For Terrazzo Finish below).
As with colors, marble chip sizes can be combined to create variations in the appearance of the Terrazzo. Terrazzo chip sizes have limitations based on the type of Terrazzo systems being used. (See Allowances For Terrazzo Finish below).
Terrazzo Divider Strip Layout / Patterns
White alloy zinc and brass divider strips are used in Terrazzo for function and Aesthetics. The
dividers strips is some systems act as control joints, transitions between Terrazzo colors,
transitions from vertical to horizontal installations, and for termination to adjacent flooring finishes.
Divider strips are commonly used aesthetically to create custom designs and patterns in the Terrazzo.
Intricate logo artwork and lettering can be created with Terrazzo divider strips.
Interior / Exterior Terrazzo
Terrazzo is used in both interior and exterior applications. Portland Cement and Polyacrylate
Matrix Terrazzo can be used for both interior and exterior applications, however. Epoxy Resin Matrix
Terrazzo is not recommended for exterior use. When optimum slip-resistance is desired for an
exterior Terrazzo surface, Rustic or Acid Washed Portland Cement Terrazzo can be used.
After grinding and before final polishing and sealing, a mild acid solution is applied that will dissolve the Portland Cement matrix until neutralized. This process leaves a slight depression in the matrix causing the marble chip surface to protrude slightly and provide the added slip-resistance. Upon final sealing, the Terrazzo appearance is similar to polished Terrazzo without high gloss.
After grinding and before final polishing and sealing, a mild acid solution is applied that will dissolve the Portland Cement matrix until neutralized. This process leaves a slight depression in the matrix causing the marble chip surface to protrude slightly and provide the added slip-resistance. Upon final sealing, the Terrazzo appearance is similar to polished Terrazzo without high gloss.
Allowance for Terrazzo Finish
When considering which Terrazzo system is best suited for the proposed application, the required minimum
thickness for each type of Terrazzo system may become the deciding factor. The following minimum varying
thickness and weight apply for each respective Terrazzo system:
- Exterior Sand Cushion / Venetian Terrazzo 2 1/2" (30 lbs./sq.ft.)
- Exterior Bonded Acid Washed Terrazzo 2" (20 lbs./sq.ft.)
- Interior/Exterior Polyacrylate Terrazzo 1/2" (3 lbs./sq.ft.)
- Interior Epoxy Resin Terrazzo 3/8" (3 lbs./sq.ft.)
Terrazzo Type Advantages and Disadvantages
Epoxy Resin Matrix Terrazzo:
Advantages:
- System thickness of 3/8" total, can be used over concrete or wood substrate
- Virtually unlimited range of vibrant colors available
- Glass chips can be used in epoxy resin Terrazzo
- Design flexibility due to minimal divider strip requirements
- Accelerated chemical cure allows for faster installation due to significantly decreased cure time prior to grinding
- Color uniformity on large installations due to sophisticated manufacturing process for resin
- Most cost effective system for interior use
Limitations:
- 3/8" total thickness requires high flatness tolerance of 1/4" per 10 sq.ft. in the substrate.
- Not recommended for exterior use.
- System not breathable, moisture vapor transmission barrier may be required for slab on grade applications.
- Maximum chip size that can be used is #2.
Portland Cement
Sand Cushion
Bonded Acid Washed Terrazzo:
Sand Cushion
Bonded Acid Washed Terrazzo:
Advantages:
- Can be used for interior or exterior use
- Can be acid washed for added slip resistance in exterior use
- Topping thickness will accommodate the largest (#7) chip size
- Is breathable and not affected by moisture vapor transmission
- Sand Cushion system can accommodate substrate defects
Limitations:
- Requires minimum 2" depression for system installation
- Vibrant colors are very limited with Portland Cement
- Glass chips have limited use in Portland Cement
- Design flexibility due to size of panel limitations
- Lengthy cure time to achieve final appearance
Polyacrylate Modified Cement Terrazzo:
Advantages:
- System thickness of 1/2" total, can be used over wood substrate.
- Glass chips can be used in polyacrylate matrix Terrazzo.
- Can be used for exterior applications.
- System is breathable and not affected by moisture vapor transmission.
- Can be acid-washed for added slip resistance in exterior applications
Limitations:
- 1/2" total thickness requires high flatness tolerance of 1/4" per 10 sq.ft. in the substrate.
- The most vibrant colors cannot be achieved with polyacrylate matrix.
- Maximum chip size that can be used is #2
Epoxy / Resin Terrazzo
A nominal 1/4" or 3/8" thick resin matrix veneer placed upon a level concrete slab;
Also can be specified with glass, synthetic, or granite aggregates in lieu of marble
to provide brilliant colors or chemical resistance; The best "thin-set" system.
Click this panel to view or hide detailed information, Word, PDF and DWG CAD docs.
EPOXY TERRAZZO DOWNLOADS:
Word Doc - Epoxy-Venetian Terrazzo-without-LEED
PDF - Epoxy-Venetian Terrazzo-without-LEED
Epoxy Terrazzo Advantages:
Unlimited matrix colors, color control, resiliency, chemical resistance and tensile-
compressive strengths not found in cement based systems. Excellent for multi-colored
patterns and designs. Light weight and flexibility make it ideal for multi-story use.
It has the lowest maintenance cost due to non-absorbancy. In sanitary areas can be
installed with minimal dividers providing seamless characteristics. When used in
conjunction with a flexible membrane as a specified extra, it can absorb some horizontal
concrete crack or control joint movement. It also has the quickest pour to grind installation
time. Can also be used over properly installed and prepared plywood. Glass and other
decorative aggregates increased costs.
Thickness: Nominal 1/4" or 3/8" Epoxy Terrazzo topping. 0-1 chip sizes opt.#2 chip for 3/8".
Weight: 3-4 lbs. PSF.
Thickness: Nominal 1/4" or 3/8" Epoxy Terrazzo topping. 0-1 chip sizes opt.#2 chip for 3/8".
Weight: 3-4 lbs. PSF.
Dividers:
Most systems adhere to the concrete and require dividers to be placed precisely above any concrete
joints. To prevent the concrete from cracking and therefore the terrazzo, "ACI 302.1 R.89 Concrete
Joint Placement" must be followed. Some of these requirements include: Concrete joints should occur
a maximum of three times in feet the depth of the concrete in inches. (Example: A 4 inch slab should
have concrete joints at a maximum spacing of 12 feet). Concrete joints should run off all corridor
intersections and corners. They should not be spaced more than 1.5 times the width of the concrete
pour. (Example: A 6 foot wide corridor should have concrete joints at a maximum of 9 feet.)
In addition other dividers can be set to separate colors or as an accent themselves. In these systems the dividers not located over concrete joints are strictly decorative. They do not function as leveling devices or crack preventers.
Dividers vary in width from 18 gauge to 1/2 inch. 16 gauge or 1.8 inch are standards. Zinc is standard but brass and colored plastic are readily available.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
In addition other dividers can be set to separate colors or as an accent themselves. In these systems the dividers not located over concrete joints are strictly decorative. They do not function as leveling devices or crack preventers.
Dividers vary in width from 18 gauge to 1/2 inch. 16 gauge or 1.8 inch are standards. Zinc is standard but brass and colored plastic are readily available.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
End
Sand Cushion Terrazzo
A cement matrix topping underbed with wire reinforcing, isolation sheet, and sand layer system for
interior floor use. This is the best cement system.
Click this panel to view or hide detailed information, Word, PDF and DWG CAD docs.
SANDCUSHION TERRAZZO DOWNLOADS:
Sandcushion Terrazzo Advantages:
Due to the underbed's depth, wire mesh reinforcing, isolation sheeting and sand layer it will absorb
minor substrate defects and prevent mirroring to the surface.
Thickness: 2.5" to 3" including a .5" terrazzo topping.
Weight: 25-30 lbs. PSF.
Thickness: 2.5" to 3" including a .5" terrazzo topping.
Weight: 25-30 lbs. PSF.
Dividers:
The position of divider strips is essential to performance, serving a dual function: a control for
anticipated contraction and an aesthetic enhancement in separating colors. 5 feet or less on centers.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
End
Bonded Terrazzo
A cement matrix and underbed system for interior and exterior areas where conditions require 1.25" to 1.75" of recessed depth
to be filled in addition to the .5" terrazzo topping.
Click this panel to view or hide detailed information, Word, PDF and DWG CAD docs.
BONDED TERRAZZO DOWNLOADS:
Bonded Terrazzo Advantages:
With sand-cement underbed it has less dependence on the concrete slab for flatness when compared to
monolithic.
Thickness: 1.75" to 2.25" including .5" terrazzo topping.
Weight: 18-22 lbs. PSF.
Thickness: 1.75" to 2.25" including .5" terrazzo topping.
Weight: 18-22 lbs. PSF.
Dividers:
Most systems adhere to the concrete and require dividers to be placed precisely above any concrete joints.
To prevent the concrete from cracking and therefore the terrazzo, "ACI 302.1 R.89 Concrete Joint Placement"
must be followed. Some of these requirements include: Concrete joints should occur a maximum of three times
in feet the depth of the concrete in inches. (Example: A 4 inch slab should have concrete joints at a maximum
spacing of 12 feet). Concrete joints should run off all corridor intersections and corners. They should not be
spaced more than 1.5 times the width of the concrete pour. (Example: A 6 foot wide corridor should have concrete
joints at a maximum of 9 feet.)
In addition other dividers can be set to separate colors or as an accent themselves. In these systems the dividers not located over concrete joints are strictly decorative. They do not function as leveling devices or crack preventers.
Dividers vary in width from 18 gauge to 1/2 inch. 16 gauge or 1.8 inch are standards. Zinc is standard but brass and colored plastic are readily available.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
In addition other dividers can be set to separate colors or as an accent themselves. In these systems the dividers not located over concrete joints are strictly decorative. They do not function as leveling devices or crack preventers.
Dividers vary in width from 18 gauge to 1/2 inch. 16 gauge or 1.8 inch are standards. Zinc is standard but brass and colored plastic are readily available.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
End
Monolithic Terrazzo
This 1/2" thick cement matrix veneer placed upon a provided concrete slab is dependent on the concrete
quality for flatness and crack prevention. On grade or below grade only.
Click this panel to view or hide detailed information, Word, PDF and DWG CAD docs.
MONOLITHIC TERRAZZO DOWNLOADS:
Monolithic Terrazzo Advantages:
Fast installation and the most economical price make it ideal where time and budget are critical but where
the beauty, low maintenance and the performance of terrazzo is desired.
Thickness: 1/2" Terrazzo topping
Weight: 5-7 lbs. PSF.
Thickness: 1/2" Terrazzo topping
Weight: 5-7 lbs. PSF.
Dividers:
Most systems adhere to the concrete and require dividers to be placed precisey above any concrete joints.
To prevent the concrete from cracking and therefore the terrazzo, "ACI 302.1 R.89 Concrete Joint Placement"
must be followed. Some of these requirements include: Concrete joints should occur a maximum of three
times in feet the depth of the concrete in inches. (Example: A 4 inch slab should have concrete joints
at a maximum spacing of 12 feet). Concrete joints should run off all corridor intersections and corners.
They should not be spaced more than 1.5 times the width of the concrete pour. (Example: A 6 foot wide
corridor should have concrete joints at a maximum of 9 feet.)
In addition other dividers can be set to separate colors or as an accent themselves. In these systems the dividers not located over concrete joints are strictly decorative. They do not function as leveling devices or crack preventers.
Dividers vary in width from 18 gauge to 1/2 inch. 16 gauge or 1.8 inch are standards. Zinc is standard but brass and colored plastic are readily available.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
In addition other dividers can be set to separate colors or as an accent themselves. In these systems the dividers not located over concrete joints are strictly decorative. They do not function as leveling devices or crack preventers.
Dividers vary in width from 18 gauge to 1/2 inch. 16 gauge or 1.8 inch are standards. Zinc is standard but brass and colored plastic are readily available.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
End
Polyacrylate Terrazzo
A nominal 3/8" thick polymer modified cement matrix veneer placed upon a provided level concrete slab.
Polymer provides strength to allow for thinner applications of cementitious systems.
Click this panel to view or hide detailed information, Word, PDF and DWG CAD docs.
POLYACRYLATE TERRAZZO DOWNLOADS:
Polyacrylate Terrazzo Advantages:
Fast installation and moderate price range make it ideal to replace vinyl or carpet without depth
transition difficulties; also good to use in areas subject to moisture vapor transmission where Epoxy
terrazzo or other non-breathing floors will not adhere.
Thickness: Nominal 3/8" polyacrylate with terrazzo topping. Chip sizes 0,1 and 2.
Weight: 4.5 lbs. PSF.
Thickness: Nominal 3/8" polyacrylate with terrazzo topping. Chip sizes 0,1 and 2.
Weight: 4.5 lbs. PSF.
Dividers:
Most systems adhere to the concrete and require dividers to be placed precisey above any concrete joints.
To prevent the concrete from cracking and therefore the terrazzo, "ACI 302.1 R.89 Concrete Joint Placement"
must be followed. Some of these requirements include: Concrete joints should occur a maximum of three times
in feet the depth of the concrete in inches. (Example: A 4 inch slab should have concrete joints at a
maximum spacing of 12 feet). Concrete joints should run off all corridor intersections and corners. They
should not be spaced more than 1.5 times the width of the concrete pour. (Example: A 6 foot wide corridor
should have concrete joints at a maximum of 9 feet.)
Architects should design structural inset expansion plates between areas where major movement is anticipated.
Architects should design structural inset expansion plates between areas where major movement is anticipated.
End
Rustic / Exterior Terrazzo
Terrazzo with a non-ground, textured surface, for exterior use. This system is available with Bonded
and Monolithic Terrazzo.
Click this panel to view or hide detailed information, Word, PDF and DWG CAD docs.
RUSTIC TERRAZZO DOWNLOADS:
Rustic Terrazzo Advantages:
Inifinitely variable textures, colors and patterns may be created in a weather-resistant,
skid-resistant deck surface.
Thickness: Bonded 1.75" to 2" including a .5" terrazzo topping. Monolithic .5" terrazzo topping.
Weight: Dependent on system selected.
Thickness: Bonded 1.75" to 2" including a .5" terrazzo topping. Monolithic .5" terrazzo topping.
Weight: Dependent on system selected.
Dividers:
Temporary wood strips are used, then replaced by a pourable sealant inserted into the joint.
End
Restoration of Terrazzo
Please click the following Restoration of Terrazzo
link for guide specification for repair, restoration and re-finishing of terrazzo floors.
Terrazzo floors are either a cement or epoxy matrix (binder) with a variety of aggregates. Color matching existing aggregates in floors may not be exact, as these are mined products and may alter over time. A meeting to clarify the extent of repairs and expectations is recommended. This includes mapping out cracks and clarifying various repair options. Once mock-ups are approved, expectations should be better understood. It may be necessary for the contractor to reevaluate conditions once substrates are uncovered, or unknown conditions arise.
Terrazzo floors are either a cement or epoxy matrix (binder) with a variety of aggregates. Color matching existing aggregates in floors may not be exact, as these are mined products and may alter over time. A meeting to clarify the extent of repairs and expectations is recommended. This includes mapping out cracks and clarifying various repair options. Once mock-ups are approved, expectations should be better understood. It may be necessary for the contractor to reevaluate conditions once substrates are uncovered, or unknown conditions arise.