12 Jun Purpose of Divider Strips in Terrazzo Flooring
Purpose of Divider Strips in Terrazzo Flooring
Divider strips are the unsung heroes of terrazzo design. Every airport medallion, seamless hospital corridor, and every university logo embedded in the lobby floor, none of it happens without a divider strip guides the way.
Terrazzo is mostly characterized by its aggregates and its binder (epoxy or cement). Terrazzo divider strips are also an important component of a terrazzo floor. In this blog, we will dive into the purpose of divider strips and take a look at some of the options available to help you design your next terrazzo project.
What is a Terrazzo Divider Strip?
Divider strips are a think metal or plastic channel placed on the substrate before the terrazzo is poured, giving the floor its architecture, serving two purposes: Form and Function
Divider strips form the design (color zones, patterns, logos) and controlling cracking in the cured surface.
Why Divider Strips Matter More Than Most Designers Realize
Think of divider strips the way a painter thinks, having the freedom to design a masterpiece how they desire.
According to the National Terrazzo & Mosaic Association (NTMA), divider strips must align with all control joints, expansion joints, and structural crack-risk zones identified by a project engineer. Missing one area, can cause a crack transferring from the substrate directly through the terrazzo topping. Get the placement of divider strips right, and you have a floor that outlasts the building.
Divider strips are the canvas grid that makes complex terrazzo designs buildable. Installers bend strips on-site to form curves, letterings, and logos. Every color boundary in the design drawing becomes a strip in the field.
What Do Divider Strips Actually Do? (Form + Function)
Form: Defining the Design
- Color separation: Each divider strip creates a clear boundary between terrazzo colors. Projects can use anywhere from 2 to 20+ colors, each poured and troweled separately between the strips per the designer’s drawings.
- Patterns & logo creation: Divider strips are bent on-site into curves, waves, lettering, and geometric shapes. Complex waterjet-cut metal pieces handle intricate logos.
- Design freedom by system type: Epoxy terrazzo divider strips span 20-30 feet between control joints. Cement terrazzo is limited to 3-5 feet. This is the single biggest design-freedom differentiator between the two systems.
Function: Controlling Cracking
- Strips are place over all concrete joints.
- Engineers identify high-risk crack zones early in the project. Early coordination between designer, engineer, and contractor prevents costly repairs later in the floor’s lifecycle.
- For 3/8″ epoxy terrazzo, strip height must match the terrazzo system thickness exactly.
- Strips also serve as transition joints where terrazzo meets wood, vinyl, carpet, or other flooring finishes.
Divider Strip Options
Materials
Divider strips can be selected based on the type of material. When designing a terrazzo floor, you can choose from a variety of materials: aluminum, brass, zinc, and plastic strips. We will showcase some examples and discuss what to look out for when selecting each material.
Aluminum
Most epoxy terrazzo floor will use aluminum divider strips. We recommend using aluminum strips for a couple of reasons: it’s affordable, is a good source of recycled content if LEED points are relevant to your project, and is easy to use on a project to create patterns.
Zinc
Zinc is another material to consider. Zinc strips were often used in cement terrazzo installations but are less likely to be used in epoxy terrazzo installations today. Why? Zinc looks similar to aluminum; however, we recommend architects and designers select aluminum when specifying epoxy terrazzo to minimize cost and for ease of installation. Zinc will cost more than aluminum, and it is harder to grind over the strip during installation.
Brass
Another option is brass. Brass strips are used as a strong design element in the aesthetic of cement and epoxy terrazzo floors. The drawback is that is high-end material; therefore, costs more than aluminum and zinc. Be warned that the copper in brass strips can result in blue staining on or adjacent to the divider strips, noticeable in lightly colored matrixes. It is recommended to ask a terrazzo manufacturer whether their epoxy resin is compatible with brass strips.
Plastic
Plastic strips are another option to consider. Common colors are white and black; however, custom colors are available as well. This may be good for accent colors to match a university’s color theme.
Sometimes architects ask us if they can design a terrazzo floor where the strips are hardly noticeable. With plastic strips, it is possible to match the epoxy colors and have them blend with the floor design.
Divider Strip Thickness: Gauge Options Explained
Strip thickness (gauge) determines the visual weight of the line in the finished floor.
| Thickness | Visual Effect | Typical Use |
|---|---|---|
| 1/16" | Nearly invisible hairline | Minimalistic designs, hidden transitions |
| 1/8" | Standard visibile line | Most commercial projects |
| 1/4" | Bold design element | High-contrast patterns, branded floors |
When specifying 3/8″ epoxy terrazzo, dividers should match the thickness of the terrazzo system.
And finally, divider strips are used when transitioning to other floor finishes such as wood, vinyl, and carpet.
VIEW MARKETS
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