Today we're going to talk about Terrazzo Divider strips. These are an important component to the terrazzo system. Divider strips are both a matter of form and a function.
Form
So as you look at divider strips from a form perspective, there are a couple of different things that play into this. The first is material selection. Next is selecting the different thicknesses of the divider strips and also how we can form them into different patterns.
When we talk about the gauge of the divider strip this refers to the thickness of the strip when looking down on the terrazzo floor. Typically there are 3 most commonly used sizes: 1/16”, ⅛” and ¼”. Custom divider strips are available up to 2” in thickness. Below are some examples of custom divider strips. Keep in mind the heavier the gauge the more expensive. Lineal foot pricing doubles with each gauge increase. So just keep that in mind from a pricing perspective.
So obviously, there are different aesthetic impacts on your floor as you select a different material or guage.
Aluminum
Aluminum is the most widely used and considered the industry standard. It’s affordable and also polishes/bends well. Aluminum strips are manufactured using an extrusion process so they are one solid piece.
Zinc and Aluminum look nearly identical. Both are light silver strips but zinc cost 2x as much as aluminum. Zinc is a carryover from the cement terrazzo world. It worked better with cement as the binder, but now we're using epoxy resin so you don't see as much zinc strip used. The zinc dividers are a 2 piece strip. They are manufactured using a galvanized steel leg with a heavy top of zinc clamped onto the leg.
Lastly, zinc is slightly harder than aluminum so when using heavier gauges the grinding machine is more prone to ride up over the strip rather than cut through it. Aluminum is always preferred for heavy gauge strips.
Brass
Brass dividers are a real premium material. It's about 4-5x the cost of the aluminum. Brass is an alloy of copper and zinc. It is also fabricated using a 2 piece strip using a galvanized steel leg and heavy top of brass clamped onto the leg. Note due to the presence of copper it is possible to get a “bluing” effect on and around the divider strip. This is of particular concern with light colors. More on this in our Brass Bluing post.
Stainless Steel
Stainless steel is a great material and many designers want to specify it as a divider strip. We don’t recommend this as it's just too hard of a material plus is very expensive. The aluminum and zinc strips give the appearance of stainless steel but at a better price point and are not problematic.
Plastic strips are just that, dividers cast from resin. These are a fun way to bring accent colors into the floor in a non-traditional way. Standard colors are white and black. But you can also get any custom colors even clear. These strips are priced between the brass and zinc strips. Below you can see some examples of plastic strips. I know you are thinking but is the plastic strip going to be as durable and hold up as well as the metal strips? Actually they are very durable and will last just as long as the metal strips.
Examples
In the project below the designer didn't want to see the divider strip around the edges of this logo. Black terrazzo strips were used adjacent to black to terrazzo. This provides a nice clean edge without the contrast of a light color strip.
Another possible use for colored plastic divider strips is to blend into the floor. A lot of the floors we design today are very minimalistic and designers want the divider strips to disappear into the floor. Using a like-colored divider strip will allow it to blend into the floor.
Depending on the desired thickness the strip may be cut from a sheet of metal and then mounted to a mesh backer. It's always the preferred material. Using this technique you can pretty much specify whatever size you want. The example below shows a chevron terrazzo pattern with 2” wide aluminum bands separating the colors.
Functionally the terrazzo divider strips set the overall elevation for the terrazzo flooring thickness. So when specifying make sure that your strip height matches whatever thickness you are specifying. Most commonly that is ⅜” for epoxy terrazzo. Divider strips also retain the liquid mix as the terrazzo contractor pours the floor.
Dividers are like the skeleton of the terrazzo patterning. Think of a coloring book. The lines on the paper just need to be colored. Same concept with terrazzo. The strips will also serve as a divider between different colors.
Next divider strips are also used to honor any concrete joints in the slab. More on that in another post on concrete joints and terrazzo.
Divider strips are also a gauge for thickness during the grinding process. You can watch him grinding over the floor and then you'll notice right along here the strip start peeking out. So he's cutting the top of the divider strip and exposes that he knows he's that appropriate thickness.
Lastly, divider strips are used for terminating or transitioning terrazzo to other finishes.
So hopefully this helps you better understand terrazzo divider strips. As always if you have any questions please feel free to email me if you have any questions. Thanks for reading.