Terrazzo floors are one of the oldest types of flooring that ais still currently being used. They provide cement surfaces with a naturally aesthetic and affordable finish, using the qualities of coarse aggregates.
Creating a terrazzo floor turns out to be very versatile because it can be done by casting in situ or by installing prefabricated pieces. Furthermore, in order to improve its aesthetics, the composition of the coating mixture and its finish can be altered.
Terrazzo floors are used both in interior and exterior environments, from residential to industrial facilities, however, due to their nature they are more oriented towards architectural purposes, which is why they are abundant in urban environments.
What is a terrazzo floor?
Terrazzo is basically a cement mortar coating that has coarse aggregates embedded in it.
However, these coarse aggregates are not like those used to manufacture concrete, they are finely selected rocks for their aesthetic characteristics. The favorite coarse aggregates for terrazzo flooring are crushed marble stones, which can be accompanied by other rocks.
Terrazzo flooring can consist of a continuous lining that has been poured on site or of precast slabs that can be made in different sizes.
During its creation process, the mixture of this coating can be colored with pigments, and after it hardens, it can be polished or washed.
Like any other concrete floor, terrazzo has high mechanical resistance, especially against abrasion. Therefore, its maintenance is low.
Terrazzo, what does it consist of?
Terrazzo is a construction material that dates back to the 15th century and is composed mainly of marble stones and white cement mortar, which is then polished, giving it a fine finish, which generally serves as a floor.
Specifically, terrazzo is made by applying two layers of cement mortar.
1st Layer of terrazzo
The first layer is the “body” and consists entirely of Portland cement mortar.
2nd Layer of terrazzo
The second layer is called the “visible layer” and is made up of crushed marble (or granite) stones of different sizes (fine grain, medium grain and coarse grain).
Terrazzo’s composition has undergone different alterations in modern times, in addition to the incorporation of pigments, epoxy resins, latex, polyester resins and acrylics that have also been incorporated to improve its final seal.
Technical specifications of terrazzo flooring
Although terrazzo is a construction material used to cover floor surfaces, it’s necessary to consider certain aspects involved in the construction process and during its maintenance and cleaning, in order to have a material that complies to the service and safety requirements of the facility in which it is to be used.
These are the most relevant technical specifications of terrazzo:
- The installation of precast terrazzo slabs/tiles and the on-site pouring of terrazzo floors require adequate leveling and extensive cleaning of the base slab.
- The precast terrazzo tiles can be 30 × 30, 40 × 40 and 60 × 60 cm.
- Prefabricated terrazzo tiles must rest on a layer of sand with a thickness determined by the project, on which a layer of mortar with a minimum of 2 cm will be spread. It is recommended to wet the tiles before they being laid.
- For the in-situ installation of terrazzo floors, a layer of sand must be placed, generally 2 cm thick, over which a 1.5 cm thick layer of mortar will then go on top. The dosage of this base mortar should be 1:10.
- Additionally, when creating terrazzo on-site, a metal mesh must be placed over the base mortar layer when it starts to set. In addition, a 1.5 cm layer of 1: 4 dosage mortar should be applied to the mesh, which should be pressed with specialized instruments.
- Expansion joints should not be omitted in any case. These can be established by means of brass bands. They must have a minimum thickness of 1 mm and a height of around 2.5 cm. In the on-site construction of terrazzo, expansion joints must form squares with sides of a maximum length of 1.25 m. It is important that these coincide with the building’s joints.
- Polishing terrazzo in-situ must be carried out after the mortar has hardened, that is, after 5 to 10 days after the second layer of mortar has been poured.
- To increase the brightness of a terrazzo floor, the use of a crystallization system is recommended, which uses the physicochemical properties of calcium crystals to modify the appearance of its surface.
- Dry and wet cleaning techniques can be used to clean a terrazzo surface. Using neutral pH soaps or special terrazzo soaps is recommended. It is essential to leave the terrazzo surface completely dry after wet cleaning.
Uses of a terrazzo floor
As we mentioned previously, terrazzo flooring is used in multiple environments, both indoors and outdoors. However, the usual thing is that this floor is used only as indoor flooring; mostly in residential, commercial and public spaces.
Terrazzo flooring built in-situ enjoyed a great boom during the 1960s and 1970s, but due to the cost of specialized labor to do the work, this type of terrazzo construction is currently in disuse, being replaced by the installation of precast terrazzo tiles, which turns out to be much cheaper and faster.
However, precast terrazzo is a construction process subject to greater imperfections than its predecessor, since the joints tend to be inadequately leveled, so the finish is of poorer quality. For this reason, the construction of prefabricated terrazzo floors is finished with a polishing and buffing treatment.
Why use terrazzo flooring?
Terrazzo is a construction material that provides numerous advantages, despite depending on different finishing techniques to present an aesthetically attractive appearance. Among the main advantages of using terrazzo flooring, we highlight the following:
- Thanks to its hardness (provided by the marble and granite stones), this floor type has a high resistance to abrasion, shock and wear.
- It has a high degree of impermeability, due to the polishing process.
- It is easy to clean and has a low maintenance.
- Regular polishing maintenance allows to eliminate imperfections and damage caused by use and time.
- It’s longevity.