Saturday, October 18, 2014

Make Your Floors Terrific With Terrazzo

The popularity of terrazzo flooring peaked in the 1950s and 1960s as an economical option for slab construction houses in quickly developing Sunbelt states. But this versatile, durable, customizable and easy-to-maintain material deserves its second act.



Terrazzo is made of chips of marble or other aggregates suspended in a binder. It was created by 15th-century Venetian mosaic workers as a low-cost flooring material that used leftover marble scraps. The mixture was used on the terraces surrounding the workers’ living quarters. The name stuck, as terrazzo means “terraces” in Italian. Early Venetian recipes used marble chips pressed in clay and sealed with goat’s milk for sheen.


Modern-day terrazzo consists of at least 70 percent aggregate, and either Portland cement or epoxy is used as a binder. Divider strips, typically made of metal, are used as control joints and to separate areas of color. Several passes with heavy grinders and polishers with increasingly higher-grit disks create a smooth, sleek surface.


An extra kicker: Some terrazzo does not support microbial growth, which means it creates a naturally more sanitary surface and promotes a healthier indoor environment.


There are several approaches to creating terrazzo floors. While the overall look of the terrazzo material is similar with each method, the installation process of each is very different, each with its own pros and cons.


An abbreviated run-down of the three main approaches:



Thinset Terrazzo Method


This is probably the most popular installation method today. It uses an epoxy or resin instead of a cementitious binder. The terrazzo floor shown here was made using the thinset epoxy method to create the perfect flooring for this elegant contemporary home, designed by Vinci Hamp Architects. Architect Daniel Roush says he used a custom blend of a gray matrix plus aggregates in gray, white and tan to achieve the look.


The terrazzo layer is approximately ⅜ inch thick and is poured over a concrete slab prepped with an antifracture membrane. The slab also includes hydronic heat to keep the homeowners’ feet warm during Chicago winters.


What appears to be edges of large rectangular tiles are the aluminum divider strips used to help prevent cracking. Roush says many of the rectangles measure roughly a generous 42 inches by 84 inches.


The floor has no chemical sealer on it; rather, it has been honed to a 400-grit finish. “We considered porcelain and ceramic tiles for the floor finish, as well as stained concrete,” Roush says. “Concrete couldn’t give us the aesthetic we were looking for, and the available premade tile sizes were too small.”


This custom project totaled approximately 3,500 square feet of terrazzo. It was installed and finished for approximately $27 per square foot.



Nils Finne of Finne Architects says that in the renovation project shown here, his company integrated a new dark epoxy terrazzo floor in the kitchen area, adjacent to an existing lighter terrazzo floor original to the midcentury house. “After much color experimentation, we decided it was better to make the new terrazzo areas contrast to the original terrazzo rather than to try and match it,” Finne says.


Pros of the thinset method:


  • Thinnest and lightest terrazzo installation, about 3 pounds per square foot. (Cement-based terrazzo can range from 5 to 30 pounds per square foot). Its light weight allows it to be used for vertical applications, such as walls.

  • Can be installed over new or existing concrete or plywood subfloors

  • Highest color availability

  • Resistant to chemicals, mold and bacteria

  • Most crack-resistant installation

  • Easy to clean



Cons:


  • Some individuals have allergic reactions to the solvents used in this type of terrazzo.

  • It can be used only indoors, because it doesn’t breathe and the top layer can peel and fade due to UV exposure.



Floor thickness: 
¼-inch to ⅜-inch terrazzo layer above subfloor.


How to Make Your Floors Terrific With Terrazzo? Read here.



Make Your Floors Terrific With Terrazzo

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